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Discussion in 'Speakers & Subwoofers' started by terence, Dec 22, 2003.
Nice Read. http://www.hometheaterhifi.com/volum...03-part-1.html
i need to decide whether to get 2 12" DD's or just one 18". hum... choices choices.
Go for 2! You will have plenty of headroom, plus 2 subs just look soooooo gooooood together!!
thats maybe what im thinking... i have maggies, and im crossing them over at around 100hz or so, so there is SOME issue with bass imaging. plus, the configuration from right to left would be: sub, speaker, monoblock on amp stand, rack of gear, monoblock on amp stand, speaker, sub. hehe, perfectly synmetry. (im spelling that wrong, i just know it!)
Man, we have a DD 15 in the store, and that's already more than enough bass...I can only imagine what a beast the 18 inch is!! and thanks for the review!
Was the DD-18 measured outside like the SVS B4? Even if it was, the SVS still beats it across the board. But the Velodyne gets the nod for best sub of 2003? Pfft.
Ned, Note that the period didn't come right after the word subwoofer, but after technology. The technology in that sub is truly amazing, and certain props are due. They're not saying it's the best sub, has the best bang for the buck, or that it's testing bested all other subs (especially the B4+!). At least that's not how I read it. -Robb
Well, it does seem that the testing was done differently between the two subs so a direct comparison isn't easy, however: At 15hz both subs were measured at 100db. The Velodyne with 3-4% THD, the B4+ with 31%. At 25hz he measured 99.95db for the Velodyne and 99.69db for the B4+. 2.5% THD for the Velo and 3.25 for the B4+. The B4+ had between 3-5 more db for the maxium output from the 25hz and 31.5hz measurements. At 40hz both reached the same peak levels. But in all three of those the Velodyne had lower distortion. HOWEVER, both subs distortion levels were so low you probably wouldn't realize it. MSRP for the Velodyne = $4995 The B4+ sells for $3849 with Crown K1 amp and Rane EQ. The B4+ takes up 12ft^3 of space, the Velo only 5.44ft^3. Both subs are great. Different people will choose one sub over the other for any number of reasons. But where exactly did the SVS beat the Velo across the board? - Dan Hine
I agree ^^^^ and I have to get this off my chest. As a recent SVS owner, I find it really embarrassing sometimes the blind loyalty and comments that are made by other owners with no real objective proof to their statements hyping our subs and deeming them better than all others. This makes many of SVS supporters sound foolish and gives us a bad rep in many forums. I wish this would tone down. I never see a Velodyne or Hsu owner posting a "It's HERE It's HERE!" post or jumping into threads about other brands talking them down compared to SVS................this post was noting a review, not asking for comparisons............
Dan, don't forget that B4+ was tested OUTSIDE, so the measurements between the B4+ and DD-18 aren't directly comparable.
That's a real nice subwoofer and the processing/EQ technology they have is really incredible... a subwoofer with a video out? But it seems as if its clean output potential isn't near that of the B4+. I don't think distortion measurements can be compared, since the distortion of the B4+ at 100db outside would correspond to a much higher level inside.
The DD-18 is an amazing accomplishment. Velodyne is one of the industry leaders in world-class subwoofers and the extreme technology, features, and flexibility packed into this subwoofer is VERY impressive. The DD-18 is perfect for the well-heeled individual who is not a tweaker and wants to be secure in the knowledge he bought some of the best bass on the planet in a fool-proof, turn-key, user-friendly package. Unpack it, place it where you want, follow the GUI, and presto - perfect bass. The DD series is a quantum leap forward over the HGS series, and keeps Velo squarely in the hunt for some of the best bass around. Regarding comparisons to the B4-Plus "package", I think the SVS package can ultimately offer more outright performance and equal or greater tuning/EQ flexibility, at the expense of far more user involvement. I'm a serious tweaker and I would not be daunted in the least setting up my calibrated test rig and dialing in a B4-Plus package (with the Rane RE-17) in any room. But there is definitely a demographic that lacks the motivation, knowledge, and desire to be a tweaker and simply doesn't want to be bothered; the DD-18 is perfect for them and it would be first on my recommendation list for a major non-tweaker looking for plug and play world class bass. Regarding the THD numbers. Yes, the two subs were measured in completely different environments, albeit by the same tester. Doc Johnson could not get the B4 to produce any measureable distortion in his test room, so he placed it outside. According to respected (and paraphrased) sources, going from ground plane to in-room, you'll add about 4.5 dB per boundary. So corner loading is going to add 8-9 dB with another 1-3 dB for the ceiling depending on height and construction. So figure 10-12 dB just for the boundary effects. Also, in a typical 2,500 ft3 living area with a couple of openings to other room areas you might see 2-4 dB of room gain in the 16-25hz range. So going from ground plane to corner-loaded in a typical 2,500 ft3 room, you might realize 12-16 dB of additional output for the same input levels. The above might give you "some" idea of how low the THD numbers of the B4-Plus would actually be in a typical room - bordering on immeasurable per Doc Johnson himself. Next, bear in mind Doc Johnson measured the B4-Plus with all ports open, which gives a tune point of 25 Hz. 20 Hz is already 1/3-octave below the tune point, and 15 Hz is almost a full octave below the tune point. With no assistance from room gain, the 4th order B4-Plus will roll-off at 24 dB/octave below the tune point, and was probably down about 20 dB at 15 Hz compared to the 25 Hz level. Forcing the B4-Plus to generate a 100 dB fundamental at 15 Hz probably required 20 times the input power than it took to generate a 100 dB fundamental at 25 Hz. Hence the much higher THD reading at 15 Hz. IMO, Doc Johnson should have used one port plug to measure THD at 20 Hz, and two port plugs to measure THD at 15 Hz. The port plugs are an integral part of the B4 design, and they are required to flatten and extend the response to keep the subwoofer working optimally in the 15-20 Hz region. Testing ground plane at 15 Hz with no port plugs was clearly a misapplication of the intended product use, and almost bordered on abusive considering the sheer amount of power it took to generate a 100 dB 15Hz fundamental at one meter, outside, with no port plugs. Frankly I'm surprised the B4-Plus absorbed that much current without failure, and that is a testament to how rugged and powerful it actually is. Finally, you will note the MLS-based FR curve for the DD-18 and the B4-Plus are similarly shaped (the DD-18 actually rolls off more quickly). As Doc Johnson notes, MLS-based measurements are not a flattering way of looking at the FR, and really don't reflect at all how the subwoofer will actually respond in-room as measured at the listening position. Doc Johnson's MLS FR data for any of the SVS products he has reviewed can only really be legitimately compared to the MLS FR data for other subwoofers he has also reviewed. Anyone who compares the Doc Johnson MLS FR curves for Product A to differently generated in-room, measured at-the-seat FR curves for Product B, is doing so out of ignorance or deliberately to make Product A look unfavorable. Regards, Ed
For a closer apples to apples review comparing subs, take a look at John Johnsons review of the SVS 2531 PCi and compare it to the objective data on the Velo DD. He tested indoors and had microphone placement at 8 inches from the speaker or port depending on the frequency being played. unfortunately, he did not test maximum spl for the 2531 and he also skipped the 25 hz test signal, but he did test distortion using his 100 db benchmark for 20, 31.5, 40 and 50hz. In the 2531 review, Johnson also supplied graphs of the input signal as delivered by the amp for the test frequencies. I do have a question regarding the DD review test plots. What is the significance of the width of the various test frequencies? They look pretty wide to me, however this may not be discernable to the ear. In other words the accuracy of the output seems to be less precise at lower frequency tones. Since the gap narrows as the frequency increases, I am assuming that you would want the gap to be narrow. He did not supply the input signals but since the amp is built in it probably is irrelevant although I would have liked to have seen it.
I sincerely hope you are not talking to me. Regardless of inside/outside/upside down/measurements with your pants on or off the Velodyne measured pretty damn good. And all I asked was where the B4+ beat it across the board... But it doesn't really matter if I'm right or wrong. All the SVS zealots will just see that I didn't say "yeah, the B4+ is equal to about 1000 DD-18's in reality" and bitch at me for not proclaiming them the king. I know how ya'll work, I've been here over 3years.
It is not in the article. Doc Johnson communicated the same to SVS while generating the test report, and SVS in turn shared that information with us via the forums. I have no reason to disbelieve that statement.
So you hold no validity to quasi anechoic testing and MLS filters? Fair enough.
The Velo did these numbers with the microphone 18 inches from the subwoofer indoors. The B4+ was tested outdoors and the microphone was 1 meter away. I would think that if the mic distance on the B4 was cut in half that the db's would increase. The distortion would have been less for the 100 db test portion. Also, it's not clear to me that when Johnson did his maximum spl test at 18 inches, if he in fact was using MLS filters, the graphs only show the 100 db reading and corresponding THD. The velo is certainly plenty of sub for most people. But given the way the servo clamps down on distortion below 31.5 hz, and if you are trying to eq for a flat response to 20 Hz. It would seem that without significant room gain at the seats, you would be unable to play movies much above 10 db below reference without getting your flat curve out of shape.
Not true, Dan. My first post clearly states the two curves are similar and comparable. I was referring only to the THD data. Please do not try and take my statements out of context.
I didn't "try" to. I DID! But unintentionally.
Yeah, close proximity mic, MLS filters...thus doing away with, in part but not entirely, room gain. Or maybe I just don't know what enough of what I'm talking about yet. I really only replied to this thread in the first place because there was a completely unwarranted slight of an absolutely killer sub. And in a listening room, watching a movie I don't think many of us need 130dbs...I don't think I've EVER reached 115db peaks; too damn loud! So in typical everyday use I don't see there being a huge difference like some people want there to be.