-

Jump to content



Photo
- - - - -

$400 Sub Face-off: SVS PB10-ISD Takes On a Few Competitors


This topic has been archived. This means that you cannot reply to this topic.
46 replies to this topic

#1 of 47 Wayne A. Pflughaupt

Wayne A. Pflughaupt

    Producer

  • 5,910 posts
  • Join Date: Aug 05 1999

Posted January 06 2005 - 11:22 AM


SVS Takes on the Industry Giants

Subwoofers evaluated:
Infinity PS-12 $449
JBL E150P $402
SVS PB10-ISD $429
Velodyne VRP-1200 $349



INTRODUCTION

"Who, me?"

That was my reaction when I got an e-mail from Ron Stimpson of SVS a few months ago asking if I would be interested in evaluating SVS’ new entry-level subwoofer, the PB10-ISD.

Naturally I said yes. Wouldn’t you? Posted Image

However, between the time I agreed and the time it was delivered, Ed Mullen and a few others had posted some excellent reviews on the sub. I’m talking outstanding reviews, from a technical/execution standpoint. Even better than what you usually see in the glossy magazines these days. So I’m thinking, "Well, gee. How am I going to top this?" I don’t have a laptop or high-tech software programs, so I figured I’d have to come up with something that hadn’t been done yet.

SVS has openly claimed that their goal was to create a new deep-bass standard for the crowded $400 price range, so it made perfect sense: Why not see how the PB10-ISD stacks up to some of the competition?


Posted Image


Naturally SVS has what some might call an unfair advantage in that the company sells manufacturer-direct, so I considered pitting the PB10-ISD against some higher priced models to make the playing field more level. But in the end I decided the only thing that mattered was the "price of admission" – i.e., what the buyer gets for his money – so I elected to keep fairly close to the $400 range.

So, off I went to the local big-name electronics discounters in search of some contenders that I could shamelessly "borrow" for a few days (don’t look at me like that, I didn’t write their generous return policies! Posted Image ).

At Circuit City I picked up an Infinity PS-12 for $449. They also had the Velodyne VRP-1200 priced at $399, so I asked the befuddled sales lady for one of those, too (I got the feeling she had been borrowed from some other department for the day). However, after she rang up the Velo I saw it was only $349, which was below my target price range. Oh well – must have been on sale or something...

At Best Buy I was torn between the JBL E150P and Klipsch KSW-10, both costing right at $400. But just the day before I had caught a thread at the Home Theater Forum about the KSW series, and the general consensus was that this model line from Klipsch is pretty much low end. So I went with the JBL. I figured these subs probably have their work cut out for them going up against the PB10-ISD – no sense wasting time with one that’s a known lost cause going in.

So now we have a few candidates drafted to take on this brazen Johnny-Come-Lately contender for the $400 crown. How will they fare? We’ll see. Buckle up and pour yourself a cold brew - we’re fully evaluating four subs here, and this ain’t the Readers Digest version. Posted Image


OVERVIEW

With my contestants lined out, the first order of business was to dissect them for a build-quality inspection.


Infinity PS-12


Posted Image


Published Specs/Description
Infinity’s PS-12 is a rear-ported design with a 12-inch driver. The owner’s manual gives frequency response as 25-150 Hz +/-3 dB, and amplifier output as 300 watts RMS.

On the rear panel, the variable crossover sweeps from 50-150 Hz, with excellent 24 dB/octave slopes. A "Normal/LFE" switch fully disables the crossover in the "LFE" position.

The back panel has the standard left and right RCA line-level inputs, with labeling instructing that either the left or right jack can be used for LFE from a Dolby Digital receiver.

The rear panel also includes speaker-level inputs, but curiously no corresponding outputs. The manual indicates these inputs are for a traditional stereo system, and instructs that the connections should parallel with the receiver’s speaker terminals.

That may seem peculiar, but this is actually a fairly clever design. It’s common knowledge that the passive crossovers associated with a sub’s speaker level connections can degrade the main speaker’s sound quality. With Infinity’s connection scheme, the high-level inputs function only to provide a signal for the sub. Pretty nifty. High-quality, gold-plated binding posts are provided, even though cheaper spring-loaded clips would have been more than adequate for this application.

What isn’t stated in the manual is that the mains will have no high pass filtering. However, there are good instructions for integrating the sub into a two-channel system, logically informing the user to set the crossover frequency lower for large speakers and higher for small.

Would that the manual’s instructions for setting the phase switch were as helpful. It simply directs the owner to use the position that "maximizes bass output at the listening position."

According to the manual, the PS-12 weighs in at 45 lbs. and comes with a 5-year warranty.


Posted Image
Left to Right: Velodyne VPR-1200, Infinity PS-12, SVS PB10-ISD
To show relative size, the rear panels are aligned


Initial Impressions
Opening the Infinity’s box revealed adequate packaging, with thick Styrofoam top and bottom covers and ample space between the sub and box.

The PS-12 is an attractive sub, with the top and sides finished in a semi-gloss black-faux wood grain. Behind the plain-looking grille most of the front panel is finished in gray, with a large silver trim ring around the driver. Underneath are hard plastic feet, which may be a cause for concern with wood floors.

The 12-inch driver’s cone feels like plastic (although I’ve heard that it isn’t), with an aluminum dust cap. Tapping on the speaker resulted in considerable "after-ring" – not exactly the kind of thing that inspires confidence in a sub’s musical qualities.

Construction
Removing the PS-12’s speaker revealed plenty of internal insulation and a port tube flared at both ends. The Infinity’s driver is a medium-duty design with a stamped steel frame, and the electronics are housed in a fully enclosed metal box.

With the woofer removed, the PS-12 revealed some impressive-looking internal bracing, a wall-to-wall 1/2-inch MDF panel with three large symmetrically-placed square holes, and a forth round hole for the port to fit through. Which is a bit curious, since the hole is much larger than the port and is not used to support it – no reason it couldn’t have been square, like the others. Overall, the internal brace resembles a grid (or it would if all holes were square).

The Infinity’s front baffle is 1-inch MDF, with the rest of cabinet 1/2-inch. Rapping on the sides the PS-12 has the most solid-feeling cabinet of the four subs, testament to its internal bracing and overall excellent construction.


JBL E150P


Posted Image


Published Specs/Description
As the pictures show, the JBL E150P is physically the smallest sub in this group, a 10-incher with a large down-firing port.

The manual vaguely gives frequency response as "27 Hz to whatever setting is used on the crossover," with no figure for +/- deviation listed. The crossover frequency is variable from 50-150 Hz, with no slope mentioned. Amplifier output is given as 150 watts RMS, 250 watts dynamic power.

The E150P’s rear panel is identical to the Infinity PS-12, which shouldn’t be a surprise – both JBL and Infinity are owned by Harman International Industries, a large conglomerate of consumer and professional audio companies. Therefore I won’t repeat a description of the E150P’s controls; readers can refer to the PS-12’s description above.

The JBL’s manual has good, fairly detailed explanations of the sub’s controls, much better than Cousin Infinity’s manual. Unfortunately, explanations on using the phase switch are as poor as with the Infinity.

The E150P is the lightest sub in this group, weighing a mere 33 lbs. As with the Infinity, JBL offers a 5-year warranty.

Initial Impressions
The E150P was well packaged with thick Styrofoam top and bottom pieces and adequate internal space between the box and the sub.

The 10-inch driver has a plastic cone, and it’s similar in appearance to other JBL woofers in both their consumer and professional speaker lines. The cone resonates at a very high 80 Hz when you tap on it – not exactly the kind of thing you want to hear from what’s supposed to be a subwoofer. As with Cousin Infinity, there was some lingering “after-ring” when the cone was tapped, although not as much. The bottom-firing port is huge, big enough to put your fist into. The cabinet sits on four impressive, hunky-looking plastic feet that have tapered rubber bottoms.

The front panel is a medium gray color, the sides a semi-gloss black-faux wood grain. The driver is flanked by a plastic trim ring that’s a lighter shade of gray, and the two are bolted to the front baffle with very cool looking chrome plated, hex-head wood screws ( boy, sure wish I could get some of those at the local hardware store!). Overall, the JBL is quite an attractive package.

On the top panel is a power status LED, right up front and center, that shows if the sub is active or in standby mode. Not a bad feature; the other subs have the status LED on the rear panel, which means it usually will not be seen.

Construction
Removing the E150P’s woofer revealed more similarities to Cousin Infinity. The electronics are housed in a similar if not identical metal box. Even the internal wiring looks the same; the speaker leads are the same colors, with the same quick-disconnect connectors covered with clear hear shrink. The driver is a medium-duty design with a stamped steel frame. The cabinet’s front baffle panel is 3/4-inch MDF, the sides 1/2-inch. There is no interior insulation or bracing; nevertheless the cabinet feels pretty solid when you rap on it.


SVS PB10-ISD


Posted Image


Published Specs/Description
The SVS PS10-ISD is a ported design with a 10-inch driver and the only sub in this group with a front-firing port.

Curiously, the manual carries no performance specifications; you’ll have to be content to get them from SVS’ web site. The PB10-ISD page gives the sub’s frequency response as an astonishing 18-100 Hz +/- 3 dB. Amplifier power is given as 300 watts from a BASH digital amp.

Aside from the omission of performance specifications, the PB10-ISD’s manual is excellent and very detailed. It even lists numerous examples of specific passages from movies with scenes rich in low bass content. The manual comes shipped in protective plastic bag that includes a couple of spare fuses and an SVS pen.

Anyone perusing SVS’ website for specs on the PB10-ISD will notice there is no information on its crossover. This is because it doesn’t have one. SVS determined that probably 90% or more of home theater enthusiasts use the internal crossover in their receiver, not their subwoofer. Thus SVS eliminated the crossover and high-level speaker inputs as a cost saving measure.

The lack of an internal crossover and speaker level inputs means the PB10-ISD’s rear panel is fairly austere: A single RCA input jack, knobs for level and continuously variable phase, and a power switch. The continuously variable phase control is essentially an analog delay adjustment that helps time-align the subwoofer with the main speakers, better assuring smooth response through the crossover region. It’s a highly useful yet unusual feature for a sub at this price.

The PB10-ISD has a heavy duty detachable power cord, for those of you into such things – buy a better one and you’re sure to improve performance at least 30%!

The SVS weighs in at 60 lbs. – again, information culled from SVS’ website, not the PB10-ISD’s manual. The SVS was easily the heaviest sub in the group by a considerable margin; it was no problem picking up the others to move around for testing, taking pictures, etc. But with the SVS it was, "O-o-kay, where’s my dolly?"

The PB10-ISD comes with a 3-year warranty.

Initial Impressions
The PB10-ISD comes packaged in an oversized double-walled box. Instead of Styrofoam top and base insulators, there are large blocks at all corners to give ample space between the box and the sub. Suffice it to say, the SVS would have to sustain some serious abuse in transit to arrive at your door damaged. Inside the box was a large padded envelope with a SVS T-shirt – a nice perk.

In contrast to the other subs in this evaluation, the PB10-ISD has a no-nonsense, utilitarian appearance: No glossy panels, no faux wood grain finish, no high-contrast trim rings to dress out the driver. The only nod towards aesthetics are rounded corners for the side panels. The porous grille cloth is stretched over a sturdy 1-inch MDF frame with rounded front edges – which means that with the grille in place, all front-visible panels have rounded corners. Nice.


Posted Image
Left to Right: SVS PB10-ISD, JBL E150P


The front port has visible screws, not nearly as clean looking as the other subs’ ports. Fortunately everything is black – screws and port – so it isn’t noticeable until you get up close and personal.

Rolling the SVS over reveals that it sits on six small, pointed rubber feet that screw into threaded sockets imbedded in the cabinet.

The basis of the PB10-ISD’s "strictly business" facade is its finish, an unusual vinyl coating that’s available in four colors, white, black, tan and gray. My sample came in the light gray color, reminiscent of office work-place décor, and looked quite attractive.

Construction
When I went to remove the PB10-ISD’s driver, I was pleasantly surprised to see it is secured with T-nuts and heavy-duty 1-inch machined 10-32 screws. Very impressive. This is the stuff of professional-grade sound reinforcement speakers, not speakers manufactured for the home market.

Like the other subs’ drivers, the one in the SVS has a stamped steel frame, but that’s where the similarity ends. As you can see from the pictures, the PB10-ISD’s 10-inch woofer is a heavy-duty monster, probably weighing close to 20 lbs.

The weight and bulk of the woofer made it a little tricky to remove from the cabinet. Adding to the challenge were barely long enough speaker leads, which would strain and yank off of the flimsy-looking metal connection tabs, leaving them bent and twisted. After a few times doing this and bending the tabs back into position, I was concerned they were going to snap right off. Fortunately, this should never be an issue for the average user, who presumably won’t be dissecting his subwoofer in such a manner.

Removing the driver I found a small black screw stuck to the magnet. Hmm, not good! I got a flashlight and peered down inside around the rear-mounted electronics but couldn’t see any obvious place it might have come from. Hopefully it was picked up on a workbench during assembly.

Looking for the missing screw I couldn’t help but notice the amplifier and associated electronics. I don’t know how SVS did it, but I sure didn’t see anything in there that looked like it was capable of putting out 300 watts!

The internal speaker leads appear to be an adequate 16 gauge. That’s larger than the leads in the other subs, but I was disappointed to see that the female quick-disconnect terminals had yellow insulators, which is the size and color for 10-12 gauge wire (terminals with blue insulators would be correctly sized for 16 gauge wire). Fortunately, the crimped connections were secure, so it should never be a problem.

Inside the cabinet, the port is flared at both ends. There is insulation on all four sides, but no internal bracing. Like everything else about this subwoofer, construction is heavy-duty all the way, with a 1-inch MDF front baffle with 3/4-inch side and rear panels. However, rapping on top and sides of the cabinet brought the dreaded hollow sound, indicating that the PB10-ISD could benefit from some internal reinforcement, the extra-thick panels not withstanding.


Velodyne VRP-1200


Posted Image


Published Specs/Description
Like the Infinity, the Velodyne VRP-1200 is a 12-inch rear-ported design. The manual gives frequency response as 29-140 Hz +/-3 dB, and amplifier output as 130 watts RMS, 195 watts dynamic power.

The variable crossover frequency is adjustable from 50-200 Hz, but the manual gives no mention of the slope. There is no provision for bypassing the crossover, other than setting it to the highest frequency. The back panel has the usual left and right RCA inputs, and also present are speaker input and output connections with spring-loaded terminals. Interestingly, there is no power switch – the VRP-1200 is "auto on" only.

The owner’s manual says the Velodyne weighs 60 lbs., but my back tells me it weighs at least 20 lbs. less. It actually felt lighter than the 45 lb. Infinity.

The manual is fairly brief and cursory – for instance, the instructions for setting the phase switch read "play music and set it in the position that gets the most apparent low frequency output." For the crossover frequency it says essentially, "set it where you wish." Is it any wonder why people turn to the home theater forums for help with things like this?

Velodyne offers a 2-year warranty on the VRP-1200, the most parsimonious coverage in this comparison.

Initial Impressions
Opening the Velo’s box, it was immediately apparent that the packaging was not up to par with the other subwoofers. For instance, the VRP-1200 is comparable in size to the Infinity PS-12 yet comes in a significantly smaller box, reduced an inch or so all the way around. That translates to much less protective Styrofoam and internal space between the box and the sub. Consequently, I found the bottom Styrofoam insulator was cracked through, and the subwoofer had sustained minor damage to one of the lower rear corners.

The VRP-1200 is a nice looking sub, albeit more understated than the others. The side panels are the standard semi-gloss black faux wood grain. The Velodyne has a unique concave grille, and behind it the front baffle panel is a glossy piano black. Stick-on rubber feet are included in a plastic bag with the manual; they will probably come off about as easily as they go on.

Construction
Opening up the VRP-1200 revealed nothing overly impressive. There was no internal insulation or bracing, and unlike the other subs in this evaluation, the port tube was not internally flared. The driver is a medium-duty design with a heavy pulp cone and a stamped steel frame. The cabinet is 1/2-inch MDF for all panels, and it sounds hollow when you rap on it.


MEASUREMENTS

Overview
I kept the measurements pretty simple, mainly because (as noted before) I don’t have access to sophisticated test equipment or software. As such I limited my tests to 1/12-octave sine waves manually plotted with a digital Radio Shack SPL meter. I also had an AudioControl R-130 1/3-octave RTA on hand to monitor various aspects of the subs’ output and performance.

(For those who feel they need more thorough measurements for the PB10-ISD, see Ed Mullen’s excellent test report at Secrets of Home Theater and High Fidelity. For more tests and specs on the Infinity, JBL and Velodyne – sorry, can’t help you there. Posted Image )

Lacking the means to conduct extensive measurements, I thought it would be beneficial to plot frequency response in two vastly different but common settings. The primary listening and measuring location was our large family room, which is open to other areas like the dining room, kitchen and front entry. The total volume of the family room and open areas is a cavernous 6200 cu. ft. In addition, I took measurements in a smaller room, a bedroom with symmetrical "shoebox" dimensions that measures 16’ x 14’ x 8’, or just under 1800 cu. ft.

Measurements in these two rooms should prove beneficial to the largest number of Forum members, as I’ve noticed that systems in open family rooms and small, dedicated rooms in the 1500-2500 cu. ft. range are recurring themes. In both instances, measurements were made with the subwoofers corner loaded, as previous experiments I’ve conducted in both rooms have shown those locations to provide the smoothest response, extension and output.

Measurements in both rooms were taken after calibrating each sub to a reference level of 96 dB SPL (uncompensated), taken at the peak frequency in the room. In the family room the peak frequency was about 43 Hz. In other words, I adjusted the volume of each sub to read 96 dB at 43 Hz before charting their respective response readings.

Additionally I used a broadband pink noise signal to obtain a maximum SPL reading for each sub. The overall response curve of each sub in the charts below has been adjusted to reflect its maximum SPL level.

In the small room, the subs were calibrated for 96 dB at 80 Hz (uncompensated). No maximum SPL readings were taken in the small room.

The graphs are displayed in increments of 2 dB, a rather fine resolution. Please note that this will tend to make response look "worse" than if a coarser resolution had been used.



Posted Image


Posted Image


Posted Image



Data Analysis
In the family room, the PB10-ISD’s response extended down to 20 Hz, with usable output even lower. The Velodyne VRP-1200 and Infinity PS-12 bottomed out at 30 Hz, with response falling sharply at a rate of 18-20 dB/octave below that point. The JBL also extended to 30 Hz, but response practically brick-walled at that point, rolling out on the order of 40 dB/octave.

While obtaining the maximum SPL readings I discovered the SVS appears to have a built-in limiter. It brick-walled with a reading of 100 dB (uncompensated), no matter how high I pushed the volume level. (Higher SPL can be expected for all these subs in a smaller room.)

Comparing the graphs you can see the positive effect cabin gain has on bass response in the smaller bedroom. If the half-octave room mode at 34 Hz is flattened by 10 dB (as it would be if the sub were properly equalized), the Infinity’s extension improves to 26.5 Hz, compared to 30 Hz in the family room. Response below that point also improves, rolling out at 10 dB/octave, or about half the rate seen in the large room.

If the Velodyne’s peak is adjusted with an 8 dB cut, its extension improves to about 24 Hz, with response dropping 12 dB/octave from there – also a significant improvement over the large room.

It would appear from the small room chart that the Infinity’s output at the lowest frequencies is significantly greater than the Velodyne’s. However, keep in mind that (unlike the large room) the small room chart does not reflect maximum output levels. In other words, the Velodyne’s level could easily be adjusted to compensate, and – considering the small room - most likely without a headroom penalty.

The JBL benefited practically nothing from the small room; even smoothing its third-octave peak by 6 dB, extension effectively dead-ends at 30 Hz, just as in the large room.

The SVS’ low bass output speaks for itself. The ability to maintain flat response at the lowest frequencies in the large room translates to a rise in the small room of about 12 dB/octave, where the other subs are falling off at about the same rate (or more). As a result, the PB10-ISD’s output at 20 Hz is 18 dB higher than the Infinity and 22 dB greater than the Velodyne – impressive figures to say the least. Suffice it to say, the PB10-ISD’s extension in a small room can only be described as phenomenal.


SUBJECTIVE LISTENING EVALUATION


Reference System

Rather than go into details on the gear used for this evaluation, readers can refer to my equipment list at this link (yes I know, some updates are in order Posted Image ). The configuration has rearranged a bit of late, but since this is a subwoofer evaluation the only change that bears mentioning is that I’m currently using the Yamaha DSP-A3090’s internal crossover and mono sub output, instead of running two-channel from the main outs and through the AudioControl PCA-III crossover. The Yamaha has a 90 Hz, 24 dB/octave low pass filter. All listening tests were conducted in the family room, unless otherwise indicated.

My reference subwoofers are a quasi-DIY rig using a pair of 12-inch Shivas in undersized 2.4 cu. ft. sealed cabinets. I say "quasi" because I didn’t build them myself; I gutted some 1970’s vintage tower speakers I had laying around and pressed them into duty. I’m referring to them as "reference subs" only because they’re what I’m used to listening too, not because they’re anything special. Posted Image

The Shivas are each driven with 325 watts from an Adcom GFA-555II amplifier, and equalized with a 1/3-octave AudioControl C-131. To make up for extension lost to the small boxes, a 9-dB boost at 25 Hz is required. The penalty, naturally, is a loss of headroom from both the drivers and amplifier at the lowest frequencies. Even if they’re stretched to the limit at times with some high-impact action movies, I’ve been very happy with these "throw-down" subs for both music and movies.

For my listening evaluations of these subs I incorporated a single filter from the C-131 equalizer, a 6 dB cut at 40 Hz. As the response charts show, I have a peak in my family room centered about there, and I felt a general "courtesy filter" would take the edge off the peak and better allow me to hear the subs instead of the room.

While setting up the first sub for evaluation, I immediately learned how poor the recommendations in the manuals are for setting the phase switches. Playing broadband pink noise, when the phase was switched from 0 to 180 degrees, my RTA revealed that response jumped 4-6 dB between 50-80 Hz, creating an unwanted peak. So much for the theory from the manuals, "choose the setting that gets the most bass output." Consequently I left the phase switch on the "0" position for all the subs.

Strangely, the RTA showed that the SVS’ variable phase control gradually sucked out response as it was turned from 0 to 180 degrees. Response shelved at 40 Hz and rolled out above that point to 100 Hz, with the worst results happening at a full 180 degrees. Clearly, you will need a high-resolution software based RTA package to optimize the proper phase setting.


Posted Image
Front to Rear: Drivers for Velodyne VRP-1200, Infinity PS-12, SVS PB10-ISD


Movie References

U-571, Chapter 15, "Depth Charged"
This is my favorite sub torture test. The exploding depth charges at 1:19:40, and at other places in the movie, extend solidly and prolifically to 25 Hz, and probably lower (25 Hz is the lowest indicator on my RTA). At my reference level for this movie, my amplifier will clip and the Shivas are on the verge of bottoming out. The bass is so low, so loud and so powerful I can feel it pummeling my entire body; even the couch vibrates. Hey, who needs shakers? Posted Image Needless to say, a subwoofer system has to move a lot of air to convey this visceral feel in a room as large as mine.

I was surprised to see that none of the store-bought subs bottomed out in this scene; indeed, only the SVS appeared to be operating at its excursion limits. The Infinity PS-12 and SVS PB10-ISD were the only subs able to convey a little of that visceral feel I was looking for – a pleasant surprise for the Infinity considering it delivered the same extension figures as the Velodyne. Possibly this can be attributed to the Infinity’s increased amplifier power and resulting headroom; the Infinity's driver visibly exhibited more cone movement than the Velodyne during this passage.

The SVS sounded very impressive with this chapter, as good and as extended as my reference subs. Naturally it couldn’t move enough air to convey the visceral feel of my dual throw-down subs, but it easily bested the others in extension. I could tell the limiter was restricting the visceral impact during the most demanding passages. Indeed, the lack of a limiter may well be what put the Infinity on the map in this regard.

The PB10-ISD also bested the others in passages where depth charges quietly explode in the distance – low level, but tons of ultra-low freq content. To their credit, the VRP-1200 and PS-12 didn’t do too badly here.

The JBL – what can I say? It really wasn’t doing anything for me in this chapter, and the RTA showed why: The E150P was rolling out hard by 31.5 Hz – too high to relay the impact I was looking for. Such a high roll-off meant the E150P couldn’t deliver the goods on the low-level explosions, either; the other subs handily bested it in this passage.

Lord of the Rings: The Fellowship of the Ring, Chapter 1, "Prologue"
This chapter is a serious subwoofer torture test, featuring at least a couple of dynamic bursts of ultra-low frequency energy. One of them is when Sauron’s ring finger is cut off and it falls to the ground at 3:59. There a burst of low frequency energy at 25 Hz and below that makes my amplifier clip and extends my Shivas to their limits. A few seconds later there is a low frequency sweep that starts above 100 Hz and descends to at least 20 Hz or below – the ultimate extension test!

The SVS was definitely getting the extension, but the limiter prevented it from conveying the burst of energy. However, in my small room with the volume reduced appropriately, the burst came through, although not as forceful as I’m used to hearing. Naturally, the descending sweep was stellar. Even in the family room you could hear it go all the way down and abruptly stop. I’d have to say the PB10-ISD edged out my throw-down subs with this passage.

The JBL just rumbled annoyingly through most of this chapter, exuding excessive energy in the neighborhood of 50-63 Hz, an octave or more above where the low frequency action was. It was really distracting. To its credit, the E150P’s driver didn’t overdrive at the finger drop. It moved fairly violently, but couldn’t relay the impact at all.

Unfortunately, I had returned the Infinity and Velodyne before I had the Lord of the Rings disc available, so I can’t say how well they would have performed with this chapter. However, I think we can reasonably assume from their performance with U-571, and from the music evaluation that follows, that they would have fared better than the JBL, but not as well as the SVS.


Music References

Basia, London Warsaw New York
On track 1, "Cruising for Bruising," the bass instrument has a very subtle texture that can be a challenge to resolve.

Track 5, "Ordinary People," features a bass line that runs two full octaves, one of my favorites for determining if a system has linear bass response. The upper notes should be clearly heard, the lowest notes felt as well as heard, with notes in between a smooth blend between the two. However, the lowest note at 2:53 are recorded with the fundamentals somewhat weak, which means you’re hearing almost as much of the harmonics as the fundamental. So while the lowest note should be felt, it shouldn’t feel stronger than the notes just above it.

The JBL exhibited a slight one-note quality with these tracks, and the lowest notes on "Ordinary People" lacked authority. Both the Velodyne and the Infinity were better than the JBL in that respect, but nevertheless the low notes weren’t as solid as I’m used to hearing with my reference subs. In addition, I felt the Velodyne sounded slightly bloated. Overall, the SVS sounded more substantial than the others, undoubtedly due to its better extension.


Posted Image
Left to Right: Drivers for JBL E150P, SVS PB10-ISD


Basia, The Sweetest Illusion
Track 1, "Drunk on Love," is my favorite music track for revealing low frequency detail. The bass guitar has a very prominent texture or "growl." Since there is a lot of mid-bass energy in the recording, it will come through on both the mains and subs. The test of a musical subwoofer, naturally, is how well it conveys the "growl." Ideally, it should be able to render the detail and texture as distinctly as what you hear in the mains. If not, you only get the texture from the mains, while it "runs together" at the supporting lowest frequencies. A good way to tell if the sub is "up to speed" with the mains is to turn them off and listen to the sub by itself.

The prominent mid-bass in this difficult track made both the Velodyne and Infinity sound bloated. The JBL was even worse - it sounded boomy, almost unlistenable. The SVS’ superior extension gave the bass line the solid underpinning the others were lacking. None of the subs could render the texture as well as my reference subs, although the SVS was slightly better in this respect than the others.

Ramsey Lewis, Ivory Paramid
Track 2, "People Make the World Go Round," is another favorite of mine for gauging extension. The bass on this track is recorded hot, so I always have to turn down the sub to better blend with the mains. At 1:03 and other places in the song, the bass guitar line has a sequence of very low descending notes, culminating in a D-flat on the B-string of a five-string bass. Unlike Basia’s "Ordinary People" track, this time the bass has very prominent fundamentals, and the notes should exhibit increasing "feel" or intensity with each lower note. If a sub has poor extension, the lowest notes will lose intensity and sound weak. Indeed, as the notes descend you can often identify the precise note where a sub reaches its extension limit, and no longer resolves the fundamental of the lower notes that follow.

With this track the SVS had no trouble getting the lowest notes. The PS-12 and VRP-1200 did fairly well here, falling only a little short with the lowest notes; however I felt the Infinity did slightly better. The JBL sounded boomy and loose, and the lowest notes were weak.

Manhattan Transfer, The Offbeat of Avenues
This under-appreciated Grammy nominated album includes some great tracks for bass detail. Track 2, "Sassy," features a series of quick staccato triplets in the bass lineat 0:23, during the intro before the vocals begin. At 0:58 and other places in the song, the bass line does a syncopated pattern on a single note, with only a few milliseconds of "dead space" occurring as each new note is struck. If a sub isn’t fast and precise, the pattern will "bleed" together and sound more like a single long note than several shorter ones.

The E150P’s one-note quality was back for this passage, in addition to sounding loose and boomy. The Velodyne sounded bloated, and both it and the Infinity sounded loose and undefined. The PB10-ISD’s added extension gave it an authority the others lacked, but I still felt it was fairly loose compared to my reference subs.

Bruce Haynes, Love at First Sight
Track 3, "Wishes" is another favorite of mine for gauging extension and smooth response. It features a simple bass line with sustained legato notes, so it’s not especially challenging compared to some of my other reference tracks. However, the bass line spans an octave and a half, so a good sub properly blended with the mains should be able to resolve the high and low notes smoothly and uniformly.

All the subs did an acceptable job with this track. However, JBL did have some trouble rendering a clear distinction between the lowest notes and their counterparts an octave higher.


SUMMATION
After my initial music listening I was feeling that if a clear winner had emerged, it was my humble DIY subwoofers, not the ones being reviewed. None of them compared well to my throw-down rig when it came to conveying low frequency detail – not even close. I didn’t know what to attribute this to except their ported designs vs. the Shivas’ sealed enclosures.

In my mind there are three characteristics that qualify a sub as "musical": Tightness (often labeled speed), detail and extension. Actually, a sub’s ability to render detail is directly related to its speed and accuracy, so I guess you could arguably narrow the requirements down to two characteristics.

Anyway you define it, the tightness and detail simply wasn’t coming through with any of these subs the way I’m used to hearing. None of them could resolve the subtle texture in Basia’s "Cruising for Bruising" bass line at all. They could only vaguely deliver the "growl" and texture of "Drunk on Love," a far cry from the clear distinction I get with my subs. With the difficult lines in Manhattan Transfer’s "Sassy," the subs all exhibited considerable "overhang" (although the SVS was better in this regard than the others), whereas mine are tight and concise.


Posted Image


The SVS’ superior extension, while certainly impressive and noticeably better than my own subs, seemed almost too much of a good thing with music – everything sounded "heavy." Considering that the EQ boost my subs have at 25 Hz also means they roll out pretty fast below that point, I wondered if that would make a difference with the PB10-ISD.

Conveniently, the AudioControl equalizer has an optional 18 dB/octave high-pass filter with available settings at 15 Hz, 25 Hz and 35 Hz. I switched it on to 25 Hz, and the effect on the PB10-ISD’s ability to render detail was simply astounding. Suddenly there was resolution and detail in spades!

I went back through my reference tracks one at a time and the resolution the PB10-ISD was now exhibiting was simply jaw dropping. Where there was none before, the subtle texture in Basia’s "Cruising for Bruising" bass line was all there, even better than with my own subs. The prominent low freq growl in the "Drunk on Love" track was more "growly," the texture more pronounced and tighter than I have ever heard. The staccato triplets and syncopated legato notes in Manhattan Transfer’s "Sassy" were also tighter and better defined than I’m used to hearing with my subs.

So, it seems when it comes to music the SVS may be a victim of its own success. Apparently its prodigious output at the lowest frequencies can obscure the amazing detail the sub is cable of rendering. In other words, the PB10-ISD's "problem" is being too good at what it does!

Unfortunately, I had already returned the other subs by this time, so I didn’t get a chance to try them with the filter. However, all of them essentially had a "natural" filter, since they rolled out at 30 Hz – above the equalizer’s filter, with a slope as fast or even faster. So I can’t imagine that an electronic filter on top of that would have solved their inherent sloppiness.


CONCLUSIONS

I’ll have to admit that going into this evaluation I had some pre-conceived notions. I honestly didn’t expect much from any of these subs in my huge family room, since I’m barely getting the job done with dual 12-inchers driven with two times or more the power. Therefore I was pleasantly surprised to see that even with the most demanding passages, none of the subs bottomed out. So in that respect I was impressed with how well they performed, even if other criterion reveals clear winners and losers.

Aside from the SVS, the JBL E150P was the only other 10-inch sub evaluated. I’ve tried at least one high-performance 10-inch driver in my quasi-DIY boxes, and a pair of them couldn’t deliver the goods in my family room. So I honestly didn’t expect much from the little JBL.

And it didn’t surprise me. Of the four subs evaluated, the JBL was my least favorite. Its poor extension just couldn’t give bass lines in music passages the authority and foundation the other subs did. The E150P was the only sub where my notes regularly registered criticisms like "boomy," "loose," "slight one-note quality." One song even carried the criticism, "sucks on this one." With the Bruce Haynes track, the lack of extension manifested itself in a peculiar way: Notes an octave apart had a sameness to them – i.e., lacking the support of the bottom fundamental, the low note sounded virtually the same as its counterpart one octave higher.

The E150P didn’t fare much better with movies in the large family room. It rumbled a lot but could never convey anything resembling a visceral feel. There are serious doubts the JBL would be a good choice for a small room either, considering that its measurements there were as poor as those taken in the large room. Any way you cut it, the other subs eviscerated the JBL.

Certainly, the E150P is better than no subwoofer at all. It would be a nice enhancement for your computer or a system with smallish bookshelf speakers. However, for either purpose I expect it wouldn’t be hard to find a sub that could perform as well for substantially less money.

It’s harder to pick a clear winner between the Velodyne VRP-1200 and Infinity PS-12. I found both to be a near match with both music and movies.

With music, each did better with some tracks than with others. Notes from my music listening show my most common complaint for the Velodyne was "bloated." The most common complaint I logged for the Infinity was "sounds a little loose." With both subs I registered the complaint with some songs "lowest notes could be better," although I felt the Infinity did slightly better there.


Posted Image
PB10-ISD faces down my twin DIY Shivas. Yes, the SVS is upside down.
Much easier to scoot around the living room.


With movies, I felt the Infinity edged out the Velodyne with the high level depth charges in U-571 by managing to convey a little of the visceral feel I’m used to getting with my reference subs. That may have been from the Infinity’s greater power output, but to be honest, I probably could have wrung the same effect from the Velo by cranking its level a little higher.

Both the VRP-1200 and PS-12 would be a good addition to a system with bookshelf speakers and should do a fine job in a small-room home theater. Many experts agree that extension to 25 Hz is the minimal requirement for an acceptable home theater subwoofer, and my measurements show both the Infinity and Velodyne meet that criterion in smaller rooms.

If I had to pick a winner between the Infinity and the Velodyne, I’d have to go with the latter simply on a "better value" basis. I expect most people will not find the PS-12’s subtle improvement worth the $50-100 higher price tag. At the end of the day, the Infinity’s superior build quality and higher power doesn’t deliver a clear performance advantage over the Velodyne’s bare-minimum construction. Perhaps it would have if the driver didn’t have all that lingering “after-ring”...

The SVS PB10-ISD comes out on top with a considerable edge. Bass lines simply sounded better and than with the other subs, even before the 25 Hz high pass filter was employed. Its superior extension made a noticeable enhancement on any music track; bass lines simply felt more substantial and authoritative even if there weren’t any ultra-low bass notes. Clearly, better extension makes an audible difference, even if most music doesn’t have much in the way of fundamentals in the lowest half-octave (at least not the music I listen to :bigsmile: ).

Even before the high-pass filter was engaged, notes from my subjective music evaluation show the PB10-ISD was the only sub with no complaints like "bloated" or "boomy." Other positive comments included "feels more solid than the others," "extra lows make a difference – subtle but definitely there." Actually, the PB10-ISD was the only sub I noted anything in the way of compliments.

With a 25 Hz high pass filter engaged, the SVS leaves the others in the dust in terms of musicality, exhibiting low frequency resolution and detail that is simply amazing. The only complaints I had registered for the PB10-ISD, "a little loose," "not as tight as I’m used to hearing," were suddenly moot. Somehow, the SVS manages not to suffer in any noticeable way from its hollow-sounding panels.

But home theater is what the SVS was designed for, and it shines there, too (sans high pass filter, of course). While the other subs bested it in maximum output, they won that advantage at the expense of extension: None of them could convey the "feel" that only comes with prodigious output at the lowest frequencies. Give me the less-efficient sub with extension any day. I had to push my system to ridiculous levels to get my maximum SPL readings, so in real-world usage I doubt anyone will miss the PB10-ISD’s output handicap.

Admittedly, the SVS was the only sub that appeared to approach its physical excursion limits with program material, but that won’t be a problem if it is used in the medium-sized and smaller rooms 10-inch subs are intended for. Although it comes at the price of somewhat restricted dynamics, the PB10-ISD’s built-in limiting insures that it will maintain a well-behaved composure when driven to the max; it won’t interrupt your movie with rude noises. If I wasn’t able to bottom it out it in a 6200 cu. ft. room, you should find the PB10-ISD’s movie performance stellar if used as intended.

Actually, if the PB10-ISD had been equalized in the small room to tame its steep rise at the lowest frequencies, it would have resulted in more headroom available to better convey impact. In rooms similar to my bedroom in dimensions and volume, this SVS appears to be the rare subwoofer that would actually gain headroom with equalizing.

In actuality, there may be other ways to get the detail the PB10-ISD is capable of without a high-pass filter, since it’s rare to find an equalizer that has one. I’ve generally recommended that when employing a house curve, the curve should shelve (flatten out) at around 30-32 Hz. This is because in my experience everything sounds “heavy” if the curve keeps rising all the way down to the sub’s limits (see more on this at my House Curve article). The PB10-ISD’s steady rise in response down to 20 Hz or lower, I’m confident, is it’s undoing, and shelving at around 30 Hz should be sufficient to get that marvelous detail happening. If not, then perhaps EQing for a bit of droop below 25 Hz. There should be no penalty with movies, since the exaggerated response built into the program material will essentially override any shelving. However, with a programmable equalizer like the Behringer Feedback Destroyer, separate memories could be set up for movies and music, with less taming of the lowest lows. Either way, you’ll have the best of both worlds: A monster sub for movies that can shake the walls, and a polite, refined sub for music. Win, win!

In the PB10-ISD discussion thread that hit the Home Theater Forum back in August 2004 when news of the budget subwoofer first broke, someone asked Ron Stimpson if it was going to be a sealed design. His reply was, "While the PB10-ISD will work fantastically for music... it'll certainly give nothing up to achieve that balance. So it'll be at least as good on home theater as it is music, but it most certainly will not take a second seat to any sealed subs either."

I’d have to say SVS has certainly succeeded in both goals with the PB10-ISD. It would be hard to imagine a home theater in a small-to-medium sized room needing anything more substantial than this subwoofer. If your budget is $400 it simply makes sense to squeeze out an extra $60-70 and get the PB10-ISD. I doubt you’ll find anything in this price range that will outperform it for music or movies.

Wayne A. Pflughaupt
January 2005


Thanks to:
Donna Pflughaupt, for creating the graphs and charts, and everything related to getting the images into cyberspace.
brucek, for the marvelous Excel program we shamelessly hijacked for our charts!


My Equipment List
“A nice mid-fi system,” according to an audiophile acquaintance.

My Tech / DIY Articles and Reviews

#2 of 47 Craig Chase

Craig Chase

    Screenwriter

  • 1,453 posts
  • Join Date: Oct 21 2002

Posted January 06 2005 - 11:35 AM

Wayne, Excellent review ... And for those on a budget, the JBL is actually available from Onecall.com for $199 ... and its big brother, the EP-250 (12 inch driver, 250 watt amp) is available at Onecall.com for $264....

Wayne, VERY well thought out ... excellent descriptions, and cool pictures !
Craig Chase

#3 of 47 John Garcia

John Garcia

    Executive Producer

  • 11,532 posts
  • Join Date: Jun 24 1999
  • Real Name:John
  • LocationNorCal

Posted January 06 2005 - 12:05 PM

Posted Image very nice review.
HT: Emotiva UMC-200, Emotiva XPA-3, Carnegie Acoustics CSB-1s + CSC-1, GR Research A/V-1s, Epik Empire, Oppo BDP-105, PS4, PS3,URC R-50, APC-H10, Panamax 5100 Bluejeans Cable
System Two: Marantz PM7200, Pioneer FS52s, Panasonic BD79
(stolen) : Marantz SR-8300, GR Research A/V-2s, Sony SCD-222ES SACD, Panasonic BD-65, PS3 60G (250G)

Everybody is a genius, but if you judge a fish by its ability to climb a tree, it’ll spend its whole life believing that it is stupid.” – Albert Einstein

 


#4 of 47 Jason Dalton

Jason Dalton

    Stunt Coordinator

  • 174 posts
  • Join Date: Feb 20 2004

Posted January 06 2005 - 12:12 PM

Wow, very good review! Thanks Wayne!

#5 of 47 Matt_Smi

Matt_Smi

    Second Unit

  • 327 posts
  • Join Date: Apr 11 2004

Posted January 06 2005 - 12:18 PM

Great comparison Wayne! Really enjoyed reading it and once again just made me feel better about having discovered this forum and how much greater of a value internet direct companies like SVS, HSU, Axiom and Ascend for example provide over your common CC and BB companies. Also very interesting find about the PB10 and how running it in a 25Hz tune made in more musical.

#6 of 47 Adil M

Adil M

    Supporting Actor

  • 922 posts
  • Join Date: Nov 21 2001

Posted January 06 2005 - 01:28 PM

Let's remember shipping is $40 on the SVS bringing it closer to the ~$500 mark (470). Also, the 3 year vs 5 yr warranty. Velodyne and Infinity are known for their excellent customer service in the speaker department as well. SVS is renowned for it and JBL is probably similar to Infinity.
The same goes for Onecall. You can get this for a little less after coupon then the SVS http://ww1.onecall.com/PID_15083.htm.

Or what if I went to CC and got an Open Box Velodyne DPS 12 w/ no shipping.
The point is there are lots of variables and Wayne has written an excellent review giving us multiple reference points from which to extrapolate. This is just a very competitive pricepoint.

It's interesting how all the other subs seem to consistently rolloff at about 25 hz, but is the SVS engineered to be boosted in these areas? It could be the room effect or it could be a boost. That SVS had a meaty driver, huge magnet. The internal bracing was a nice find Wayne.
It was such a juicy "rare" review. I'm going to have to let it digest a bit. Posted Image

#7 of 47 Mike^S

Mike^S

    Stunt Coordinator

  • 84 posts
  • Join Date: Dec 10 2004

Posted January 06 2005 - 03:04 PM

Nice review! It's strange that you could not get higher than 102dB from the PB10. Ed managed to get 110dB from his PB10. I just tested my PB10 and got 110dB at 40hz.

The FR for all the subs could be flatter. Maybe your rooms are difficult to work with. Here's the FR for my PB10:

http://nike.cecs.csu...sisk/PB10-b.jpg

Great review though! I liked the comparisons to the other subwoofers. Too bad you couldn't test the JBL EP250.

#8 of 47 Wayne A. Pflughaupt

Wayne A. Pflughaupt

    Producer

  • 5,910 posts
  • Join Date: Aug 05 1999

Posted January 06 2005 - 03:44 PM

Thanks for the kind comments, everyone. Posted Image

Quote:
the JBL is actually available from Onecall.com for $199 ... and its big brother, the EP-250 (12 inch driver, 250 watt amp) is available at Onecall.com for $264....
Good price – certainly more in line with it’s performance. I was surprised that Best Buy actually sells the E150P for $3 more than JBL’s MSRP!
Quote:
Let's remember shipping is $40 on the SVS bringing it closer to the ~$500 mark (470).
Where I live the sales tax is 8.25%. That’s going to add between $30-37 for the locally purchase subs.
Quote:
It's interesting how all the other subs seem to consistently rolloff at about 25 hz, but is the SVS engineered to be boosted in these areas?
Could be; I seem to recall seeing something about that somewhere. Perhaps buried somewhere in that discussion thread. Considering its performance, I wouldn’t be surprised.
Quote:
It's strange that you could not get higher than 102dB from the PB10.
Huge room, remember? My room is three of Ed’s. Makes a big difference. Posted Image

Regards,
Wayne A. Pflughaupt

My Equipment List
“A nice mid-fi system,” according to an audiophile acquaintance.

My Tech / DIY Articles and Reviews

#9 of 47 steve nn

steve nn

    Screenwriter

  • 2,420 posts
  • Join Date: Jan 12 2002

Posted January 06 2005 - 05:37 PM

Nice job Wayne. That had to take time and effort. I'm going to let it sit awhile and then reread.

#10 of 47 Mike^S

Mike^S

    Stunt Coordinator

  • 84 posts
  • Join Date: Dec 10 2004

Posted January 06 2005 - 06:32 PM

Quote:
Huge room, remember? My room is three of Ed’s. Makes a big difference.


So you got higher than 102dB when you tested in the smaller room?

#11 of 47 Ilkka R

Ilkka R

    Second Unit

  • 270 posts
  • Join Date: May 19 2004

Posted January 06 2005 - 11:51 PM

Craig Chase, are you now ready to admit that cutting sub higher will make it sound more musical and tighter? Posted Image

#12 of 47 MikeDuke

MikeDuke

    Stunt Coordinator

  • 248 posts
  • Join Date: Jul 06 2004

Posted January 07 2005 - 12:35 AM

Wow
What a great review Posted Image. Very well organized and presented.
I know what I like when I hear it

#13 of 47 Craig Chase

Craig Chase

    Screenwriter

  • 1,453 posts
  • Join Date: Oct 21 2002

Posted January 07 2005 - 12:41 AM

Ilkka ... In a simple word ... NO. I have a pair of Maestros here that are flat to 13 Hz in my room, and they are quite musical.

I have only tested more than 50 subwoofers over quite a few years, and properly done bass extension does NOT make a subwoofer less musical.

Ridding a subwoofer of bloated deep bass WILL help it sound more musical, sure. But Ilkka, that just means the subwoofer in question was not that great of a design in the first place.
Craig Chase

#14 of 47 Jack Gilvey

Jack Gilvey

    Producer

  • 4,952 posts
  • Join Date: Mar 13 1999

Posted January 07 2005 - 12:54 AM

Good read...thanks for putting in the effort!


Quote:
It's interesting how all the other subs seem to consistently rolloff at about 25 hz, but is the SVS engineered to be boosted in these areas?

According to this review, it's +/- 1dB from 19Hz on up ground plane.
SVS Customer Service
http://www.svsound.com
sales@svsound.com
techsupport@svsound.com

#15 of 47 Chuck_W

Chuck_W

    Second Unit

  • 397 posts
  • Join Date: Dec 07 2003

Posted January 07 2005 - 01:13 AM

Great, well written review Wayne. This is the type of thing that keeps me coming back to this forum...and kinda makes me wish I had the need for another sub!

#16 of 47 Max F

Max F

    Second Unit

  • 250 posts
  • Join Date: Jun 26 2004

Posted January 07 2005 - 01:32 AM

Very nice review. Posted Image

I'm convinced now that group delay has very little to do with why people like sealed subs for music. Its the natural rolloff of frequency response, or better yet, the rolloff in sealed subs work best with most rooms (room gain) to create a flatter response.

Thats it! I'm going to build a tempest sub that is ported and just equilize that baby (with my BFD) to sound tight as a drum. As long as the port is tuned very low, the group delay isn't going to be a factor in music. It may not be much of a factor anyway. What most people are hearing in fat or loose bass is the resonance of the room from those standing waves.

#17 of 47 Ilkka R

Ilkka R

    Second Unit

  • 270 posts
  • Join Date: May 19 2004

Posted January 07 2005 - 01:59 AM

Craig, okay I should have said that cutting a low tuned ported sub higher will make it sound more musical and tighter. Posted Image

#18 of 47 Nigel Hooper

Nigel Hooper

    Stunt Coordinator

  • 208 posts
  • Join Date: Jun 30 2004

Posted January 07 2005 - 02:08 AM

Ilkka drop it.

#19 of 47 Ilkka R

Ilkka R

    Second Unit

  • 270 posts
  • Join Date: May 19 2004

Posted January 07 2005 - 02:22 AM

Quote:
I have only tested more than 50 subwoofers over quite a few years, and properly done bass extension does NOT make a subwoofer less musical.

Yep, maybe PB10 doesn't have properly done bass extension then...

Nigel, why? Isn't discussion what we want, and Wayne clearly stated that cutting PB10 higher did make it sound more musical. Can we generalize this to other subs as well? Maybe, maybe not... We need more tests.

#20 of 47 James Phung

James Phung

    Second Unit

  • 409 posts
  • Join Date: Jun 04 2004

Posted January 07 2005 - 02:35 AM

Great review. I always wondered how the pb10 would compare to comparably priced b&m subs (esp. the infinity sub to match my infinity speakers). I'm glad I went with the pb10 (it just came in 2 days ago).

I don't remember getting a T-shirt with my pb10 though Posted Image


Back to Speakers, Subwoofers & Headphones



Forum Nav Content I Follow