Pulled the trigger today! SVS20-39+ on its way! (1 Viewer)

[SVS-Ron]

Juan,

Think of setting your subwoofer to a certain "pressure" like a tire on your car (I hope you don't just fill them up till they "Look right" ;^)

No you use a meter to ensure when a sound hits it (or a sound hits your other speakers) the power level of that speaker is at the proper volume.

As discussed in your owners manual (a wonderful read if I say so myself 8^) where your volume/gain knob is on your SVS is nearly meaningless!

Please read over your manual, or go to this page and get a feel for what calibration of the SVS's level is all about. You will get more enjoyment out of ALL your speakers when you walk throug it all. For the record, we recommend you try setting all speakers to small (that 80Hz crossover point isnt' a brick wall sort of filter, your other speakers keep getting bass well below that point, but at a lower level, just as the SVS takes over).

More here, enjoy: http://www.svsubwoofers.com/faq.htm#meter

Ron

 

[Tim O...]

Juan_T,

I would NOT set your fronts to large, and your other speakers to small. You will have a very difficult time calibrating your system this way, and in fact you won't be able to calibrate it accurately. It's difficult to explain briefly, but in essence:

1. With this configuration you're telling your receiver to send information from the full audio spectrum (20 Hz - 20kHz, and in recent DVDs, as much as 5Hz to 20 kHz) to your mains. Your mains are only rated to 37Hz, so you will not hear some of the bass information sent to them from DVDs, CDs, etc. that is under 37 Hz. Also, your mains probably start to tail off a bit around 40 Hz, possibly even 45 or 50 Hz. You'll still hear information from them in that range, but it may not be with as much volume (SPL), and you may even detect some distortion. This is because you're asking a lot of your speakers, and you're also asking a lot of your receiver to drive your speakers to high volumes at such low frequency levels.

2. At the same time, by setting centre and surrounds to small and crossing over at 80Hz, you're telling your receiver to send all (more precisely, most) bass information at 80 Hz and below to the sub. Because the sub can play all the way down to 16 Hz (if you tune it that way) and can do it cleanly and with high SPLs, you will get a much truer reproduction of the information on the DVD or CD for the centre and surround channels than for the mains. It is a good idea to do this, because a) the sub has its own amp dedicated to playing these taxing signals and so it can do it better, b) the sub is designed specifically to play these signals whereas the centre and surrounds are not, and c) you are freeing up power in your receiver that would have been used to play those low signals, which can instead be used to play the higher frequency information in the DVD/CD, which in turn will give you a cleaner sound and will likely extend the life of your receiver.

3. The problem with 1. and 2. existing simultaneously is that you will have an uneven reproduction of bass information across your soundstage. The surrounds and centre will sound more like they should (i.e. you'll hear bass when it's supposed to be there), but your mains will sound thin on the bottom end. You'll notice this especially when there are pans around the soundstage--you'll notice a hole in the front when the mains don't reproduce low bass that the other channels do (in combination with the sub). Another problem is that you'll never be able to calibrate all channels evenly, because you'll always have more bass coming from the centre and surrounds than from the fronts, proportionately speaking.

4. The problem with setting all speakers to small but having say a 40 Hz crossover for the mains, 80 Hz for all other channels, and 80 Hz for the sub is that both the mains and the sub will be reproducing bass in the 40Hz to 80Hz region, whereas only the sub will be reproducing bass in the 80Hz and below region for the other channels. This will give you an artificial bass boost in the 40 - 80 Hz region for the mains, which no amount of calibration or tweaking will be able to eliminate. Your mains will always voice more bass proportionate to the other channels.

That was long-winded but clear, I hope. I struggled for quite a while on whether to set different crossovers for different channels (my receiver allows this) and read dozens of articles, until I came across some by Brian Florian, who writes for Secrets of Home Theatre and Hi-Fi (don't have the link; try a search). He explains quite clearly how a universal crossover point is the only way to go in a 5.1 or 7.1 setup if you want to remain true to the audio signal. This in effect renders variable crossovers for each channel a useless feature, again if your goal is to remain true to the audio signal. Also, when you have a very capable sub like the 20-39 PC+, you really, really should let it reproduce not only LFE, but also the low bass of your other channels, unless you have TRULY full range speakers. More power to you if you do (not many of us can afford them :O).

Tim

 

[DavidCooper]

That makes total sense....good post Tim.

One thing that makes a new SVS user confused is the presence of high quality, clean, accurate bass. Most of us were so used to bloated bass that when you hook up the SVS and start playing DVD's your kind of like "hmmm, it sounds like it's not even on" then when the low stuff hits you know it is. The regular material doesn't have the bass bloat in it anymore so you tend to think your speakers sound a bit thin.....when in reality they are more accurate now than ever before. Correct?

 

[Tim O...]

Totally correct, to me. I didn't notice a huge difference between my PB2-isd and my Athena AS-P400 for normal movie passages. Then when some strong 25 Hz and under content hit, WHOA! Things literally vibrate in the room. You can feel the low pressure waves just pulverizing everything. And no bloatedness. I'm more than happy with it. I often have to remind myself that I only paid $899 USD for it. It seems criminal.

 

[Juan_T]

Wow! Tim O thanks a lot for that post! (People like you really make a forum great, thanks for putting that much effort into a post) I guess when I felt that it was missing something when I went to small was because I have not calibrated my sub accordingly.

Thanks for that long post! it was excellent!!!

:b


I have another question,

Why would anyone then get tower floor standing speakers if everything under 80hz will not be heard from the towers? Then perhaps I should have saved money and just bought book case speakers.

 

[Tim O...]

That's an excellent question. I think there are several answers to it.

Ideally every speaker in your theatre is full range. In fact, that what the Dolby reference calls for. The problem with that is that to be full range, a speaker usually requires a large enclosure, which basically means towers. Also, truly full range speakers are usually very expensive.

If you have a true sub, i.e. one that can play to 20 Hz cleanly, has a flat response, and can hit reference or near reference levels *in your room,* then one could argue that you don't need full range speakers to get *nearly* the same performance. If I was building my system all over again and knew then what I know now, I would probably buy Axiom bookshelves all around, and a PB2-isd, maybe even a PB2+. Some people believe the imaging is better with bookshelves anyway (or maybe that's a fact; I'm not sure).

If you can't buy or house full range speakers for each channel, don't have a true sub, or are building your theatre incrementally and can't afford one for a while, as I did and as many people do, you may want to buy towers for their better bass capability. It's hard to buy the quality you really want, but do it in stages. But that's what I'll probably do next time.

 

[DavidCooper]

I agree about the bookshelf vs. floorstander issue. For HT use an all high quality bookshelf system with a GOOD sub (all properly calibrated) will sound every bit as good as full range floorstanders in the front.

A good friend of mine has B&W 804's (expensive) for fronts and he is crossed over at 80 with a sunfire sub. I have listened to his system several times and have yet to be convinced to get floorstanders up front. My set up sounds just as good..actually better due to the SVS kicking the pants off the sunfire!!!!! The cost jump from bookshelves to floorstanders rarely equals quality of sound you get for HT use.

Now if your really into 2-channel music...then I could see why someone would want to have a full range pair up front.

 

[Juan_T]

Well, I'm leaving work now and going home. I'll let you guys know how it goes.. I'm going to calibrate my sub tonight with a radio shack meter and the video essentials. Hopefully after this, I shouldn't be missing the mids when I set my front speakers to small.

You guys got me thinking.. perhaps it would be a good idea to sell my Klipsch RF-3's and get the RB-5 or RB-7 book case speakers! hmm

:b

 

[Dan Halchak]

B&Ws 805s (I think) sound better than the 804s, however the 802s sound better than the 805s. In my opinion.

The way I look at tower vs. bookshelf is a couple ways, if you have the room, great, they definitely look impressive. If you are going to use your system for 2ch audio listening, then they are the way to go as well. If you are going to use them for HT only, you can get bookshelves on stands that sound just as good (if not better sometimes) for a cheaper price.

I think it's all personal preference... I have B&W 604s floorstandings and 602s bookshelves, with the cross over at 80hz, you can barely, barely tell the difference between the two (slight better response in the low end down to 80Hz and the trail off of the crossover).

Juan_T, what I would do is set everything to small, play some really good music that has something like an orchestra (or if you aren't into that, Dave Matthews Band has some great CDs to demonstrate this with), listen to a song a couple times with large set to the mains. Then go back and listen to the same thing but with it all set to small. You will notice that you feel like you are missing something. But if you listen to the higher spectrum stuff (like violins/flutes/chimes/guitars/etc) you will notice that they seem a LOT more detailed then they did with the speakers set to Large. You will only have that feeling of missing the mid range (which

 

[Juan_T]

THanks Dan, I will do as you say.

Just calibrated my system.. Oh-my was I off big time!!

Cant wait to watch a movie.

What do we exactly define in terms of HZ to mids? from where to where? 80-400? What about lows and highs?

 

[SVS-Ron]

Juan,

Was that "Digital Video Essentials" you picked up? Some folks have had trouble getting their subwoofer set to the right level with that disk.

Ron

 

[Tim O...]

Ron's right Juan. There's a discrepancy on the disk between the surround test tones and those for the sub. Here's a long thread discussing it. Just skip to the last page for basic instructions on adjusting for it.

http://www.hometheaterforum.com/htfo...hreadid=184659

By the way Ron, I'm absolutely loving my PB2-isd. I've been tweaking for weeks, and now I've got a quite nice nearly flat response in my odd shaped room, without any EQ.

Keep up the great work.

 

[Juan_T]

Yes, it is the Digital Essentials. Thanks for the tip, I will look at the thread because I still feel like theres some tight bass missing.. I mean I do feel huge bass but not tight when my towers are set to small. Sorry, its kind of hard to describe. I have to keep tweeking. Theres also an option of setting the cross over at 80Hz + LFE+mains.. but I know that that will probably interfear with the sub and cancel some bass right? Unless I graph all the curves and play with the phase.. right? Hmm, I guess I have to keep tweaking the sub. (Sorry about all these questions.. I'm still learning)

Question, If my mains go down to 37Hz and the speakers get a signal of let say 30Hz, does that mean I'm damaging my mains? or it depends at what volume I'm playing them at?
Before I use to have a sub, I used my mains in Large and I never heard them give out a distorded low sound.


thanks guys, and thanks SVS-Ron for chiming in!

 

[Tim O...]

You probably feel there is "tight" bass missing because your sub is calibrated too hot, and so it is muddying what you hear. As was mentioned above, it can seem like you're getting less bass when you upgrade to a good sub, because there's less boom. But when you've properly set up and calibrated and you demo a very good bass scene in a DVD (try the Darla scene, the whale scene, and the sub sliding scene from Finding Nemo; also the ice fields scene in Titan AE (this one is just crushing!)), you'll know that you made a huge step up with your sub.

The only way to properly set up your sub, IMO, is to use test tones from 16 Hz to 150 Hz and graph them. Then you'll see if you have dips and peaks in your response, and you can move your sub around, play with the phase, and play with your room to get as flat a response as possible. It takes a bit of time but is well worth it in the end. If you search on this site and on Home Theater Spot in the SVS forum on "calibration" and its derivatives, you'll see lots of tips.

I would NOT set your receiver to LFE + mains. As I said above, that will give you an artificial bass boost because the mains will voice bass that the surrounds will not. Unless being true to the audio signal is not important to you and you like that extra bass (but the whole point of calibration is to get to set your system up to accurately reproduce the signal it's being fed).

You mains will have a crossover built in to them to prevent them from trying to reproduce frequencies they cannot, or else they will naturally roll off below their capabilities. I wouldn't worry about it. Unless of course you fed them low frequencies at much more power than they're rated for.

 

[DavidCooper]

Titan A.E. is an amazing disk for testing out your SVS. The whole movie is full of great stuff but the standouts are indeed "Ice Fields" and "Building a Planet". The "Building a Planet" scene has an amazingly low and continuous bass track that makes it seem like your house is going to fall apart.

That movie made us put down these little rubber mats on my wifes knick knack shelf to keep the stuff on it from jumping off.

 

[terence]

Titan A.E. never gets old when it comes to a great demo for your sub and system. Excellent disc to see what your new toy really can do! "Ice Fields" and "Building a Planet" are the two chapters I head straight for when I pop in this flick, you won’t forget these two chapters ever.

Ice Fields



The opening scene is pretty good too.

 

[Juan_T]

"I would NOT set your receiver to LFE + mains. As I said above, that will give you an artificial bass boost because the mains will voice bass that the surrounds will not. Unless being true to the audio signal is not important to you and you like that extra bass (but the whole point of calibration is to get to set your system up to accurately reproduce the signal it's being fed)."

Yes, I want to remain true to the audio signal. Will put the mains on small and the sub 80hz on LFE channel.

"The only way to properly set up your sub, IMO, is to use test tones from 16 Hz to 150 Hz and graph them. Then you'll see if you have dips and peaks in your response, and you can move your sub around, play with the phase, and play with your room to get as flat a response as possible. "

THanks Tim O, Thats exactly what I'm going to be doing saturday afternoon. I managed to get a cd which basically reproduces tones at each track from 10HZ-300HZ. (Cant remember the title of the top of my head, think is subtonez or something like that) I guess, from this I'll be able to graph and see the peaks. The problem I have is that the sub has to stay in the corner of the living room.. (no chances of moving it due to a large WAF, lol) I understand that if I have huge peaks the only way to lower them is to get a a parametric equalizer.. correct?

I'm also going to try to pick up Titan A.E., seems like it sells pretty cheap and from the comments seems to have great bass.

thanks again guys,
JT

 

[Tim O...]

You can also download tones here, as well as a handy Excel sheet already set up for plotting.

http://http://www.snapbug.ws/bfd.htm

Go down the page to this heading and you'll find the downloads:

MEASURING SUB SPL LEVELS
&
USING MICROSOFT EXCEL WORKBOOK

One way that I fixed some room nodes was by removing the bassplate from my PB2-isd, raising it 24" off the concrete & carpet floor, and orienting the drivers sideways. Ron and Tom probably cringe when they hear that, but I can't argue with the results. That's not really an option with a cylinder, however. The only other way I think you can tackle uneven response without EQ is to play with your room acoustics. You can probably eliminate peaks by placing some bass-trapping material in certain spots. Not sure what you could do with nulls. If I'm wrong about this hopefully someone will jump in and correct me.

Good luck. I bought Titan AE for $6.88 at Walmart in Canada. I imagine you could get it for $5.00 down there (I'm assuming you're in the U.S). What a steal! I think I've also seen We Were Soldiers for $10.00 or something like that. It's another terrific bass DVD and I'm going to pick it up next I see it.

 

[SVS-Ron]

Juan,

If you do the discret tone/mapping thing just keep in mind that the tones (typically sine waves) can smoke a woofer in a matter of a few seconds, even if the tone in question doesn't sound loud at all. Sine waves are NOT the same as real movie soundtracks of movies. They are continous and leave little time for the woofer to cool, so keep your runs at VERY low sound pressure levels (in the 75dB range), keep the tone itself just to a few seconds and allow a few seconds before moving on to the next tone (you have to write down the measured results of course).

Also, and this is key, a typical Radio Shack SPL meter isn't totally linear in its sensitivity to all test tones. In other words what you see reading on the meter isn't always very accurate with low bass sine waves.

You have to "compensate" (with simple math) for the inaccuracy of the RS meter. This chart here gives some basics:

http://www.svsubwoofers.com/faq_rscomp.htm

You can extrapolate some of the compensation numbers if you do a Hz by Hz plotting (we just gave it in steps).

The bottom line is that if you are measuring a 16Hz tone at 75dB it's not REALLY performing that low. The SVS (or any sub) is actually cranking out almost 87dB which is actually already pretty loud for a tone that low.

So proceed cautiously.

Ron

 

[Juan_T]

Thanks for the heads up Ron!

I'll look at the compesation values and proceed carefully.