Truthspeaker, I'm amazed at the amount of mistruths and ignorance that can be packed into a single post. Congratulations!!
:-) |
Truthseeker if you haven't tried this in your own room what you speak is nonsense.LOL
"If you can detect a difference, it's because there are now TWO subs in the room instead of one, and the strain on the single sub will now be halved"
I'll be damn you answered your own question. If there are two working less than one..you have lower distortion correct. I've not heard a single speaker that could create a stereo image all by itself. If you have please let me know. :-)
Think of the money you could save by only needing a single speaker!WoW
Have a great day! |
This whole stereo sub thing is nonsense. Hardly any info there. Hardly heard. If you can detect a difference, it's because there are now TWO subs in the room instead of one, and the strain on the single sub will now be halved. It's the transients you hear first when it comes to bass, and those transients are almost always located above the crossover point..ie..in your mains. The ONLY possible way you "might" be able to increase the "spaciousness" in your subs is if you physically locate them directly to the sides of your head (ala Lexicon pre-pros)...and even THAT is of dubious benefit. MUCH research has been done on this. If you really want to improve the bass, yeah, buy two subs...but DON'T bother running them in stereo. Either stack 'em or spend a LOT of time and effort situating them properly.
Done |
Dear Douglas: +++++ " . I believe I hear quite well the stereophonic effect of the low frequencies. " +++++
The stereophonic effect: I tottaly agree with you and that issue is all about the use of two sub's instead only one.
Regards and enjoy the music.
Raul. |
Possibly the difference between one or two subs is non-quantifiable. I certainly heard a difference when I added a second Vandersteen 2W sub to my system running in stereo. I believe I hear quite well the stereophonic effect of the low frequencies. The room certainly fills with low sound better than with one sub, and there have been no problems with nulls that I'm aware of. Currently I have ten 8" bass drivers operating and simply the presence of the additional drivers makes exceptionally deep frequencies audible. Previously, when I operated two subs (with six 8"drivers total) an incredibly low bass note was not even audible. With the addition of four more drivers it could be sensed. |
Dear Spacekadet: Why I already say that you can loose music info. With a pair subs you have stereophonic sound reproduction that is exactly how its happen at the recording event.
Example, let's take a low drum that was recorded at left side of a music hall : if you have a dual mono subs ( left/right separates ) you will hear that drum at the left side on your audio system but if your subs are sum up ( left+right ) you will hear that drum at the center of your audio system.
Regards and enjoy the music.
Raul. |
I agree with Mcreyn and some of the other guys. No doubt about it two stereo subs are very easy to discern from a mono sub or two mono subs.Infact once you hear it ..all your questions will be answered. |
Two answer your question, I have compared my two ULD-12's running in mono and in stereo. There is a difference. Remember that the left and right channel may have different phasing when picked up by the microphone. The most extereme example would be where the mike picked up the signal 180 degrees out of phase. This would result in no signal when summed to mono, when in fact there is a completely different signal from left to right. When played back the summed mono would have no output while the stereo subs will put out the signal and the listener will hear the bass as picked up by the microphone. |
I'm no professor but it seems to me you can't 'miss' any of the bass if you've summed the two channels through the sub. Its all there, how can you 'miss' any? Has anyone really compared two subs run in stereo to two subs daisey chained together? And can you honestly hear any difference or do you perceive it? I just can't believe there is. A benefit to having two subs though is another matter. I know two different people running two DD-18's in their systems... from what I hear, I want to match my single DD-18 to a sister sub... holy cow! Neither runs their other then daisy chained and both are knowledgable people in the industry. |
Dear Spacekadet: Velodyne: great choice nobody knows more about subwoofers that Velodyne people. I own two HGS-15, why two?: well not only because there are music information in the lef and right side of the recording signal but more important because those low bass ( left/right ) generate a lot of harmonics down and up the fundamental frecuency. So, if you have only one subwoofer you are missing a lot of music.
+++++ " except for a bump at 50Hz . " +++++
I can suggest that you can try other subwoofer position: side firing.
Now, the crossover point for the Totem's is very important ( critical ): which was your crossover point that you choose?
Regards and enjoy the music.
Raul. |
I'm just another guy on the internet, so my opinion is as good as the next. I would suggest that you check out the some literature on Richard Vandersteen's site as he is a big proponent of stereo subs. |
Cary, I asked the professors because they are also in the hobby and definitely know a thing or two about audio, and both hold multiple Ph.D degrees in relevant fields.
Who should I ask if these professors aren't good enough? You?
Also, those little questions on your last paragraph would be insulting to ask them. Throw me a bone here.
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As someone who has run a mono ULD-12 and then a stereo pair of them, I can tell you there is a difference. Just because the ear does not sense the direction of low frequencies, does not change the fact that the information in the low frequency signal may be (and often is) different between the left and right channel. Summing them to mono can and many times does cause cancellations and peaks due to phase cancellation.
As far as your professors having the answers, don't be so sure that because they are professors they have the answers. Ask them is two amplifiers that put out the same power sound the same? What about different speaker cables? Acoustic engineering is a specific field and just because you are an engineer proficient in EE or AE, doesn't mean you know squat about another field. |
The Velodyne DD15 is here! This thing is really ridiculous. The whole setup took me less than an hour and the bass frequency response is pretty much ruler flat except for a bump at 50Hz due to the tiny room.
I've talked to couple of my professors at U. of IL. and they convinced me that two subwoofers running in stereo makes no sense. After hearing the Velodyne DD15 in my system, I have no regrets and am no longer curious about two subwoofers.
I'm sorry to end this thread this way, but the DD15 and two professors from my Aerospace and Electrical Engineering department have convinced me that one subwoofer is all I need. |
The DD15 will be here any day now.
Sailfishben, as far as math goes, you should focus on the surface area instead of the length. The 15" driver has over double the surface area of the 10" driver. Actually more than 2.5 times as much considering the DD15 has 12.7" piston and the DD10 has an 8" piston.
I'm really happy to find a new DD15 at a really good price and can't wait to hear it!
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GREAT... so glad you obtain the 15" driver. Simple math tells you it's 50 percent larger, which as Yogi would say, is a lot! Anyway if you stumble on the set up, e-mail me. I'm no installer but... Enjoy! |
Thanks Sailfishben,
I was going to buy a Velodyne DD10 for my bedroom and then add another one when I move to my new apartment, but I found a really good bargain for DD15 and ended up ordering that... I'll update my system as soon as the subwoofer arrives.
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I just found this on the Anthem website...
Q20: I have two subwoofers and want to use them in stereo. Can the surround preamp's subwoofer outputs run in stereo?
A: No, although the same job can be done by disabling the sub channel in the setup menu, then hooking up the subs through their own crossovers to the front left and front right channels. This is not recommended because a stereo subwoofer configuration has little value. Few recordings contain real stereo bass info, (e.g. large pipe organ using widely spaced microphones) and unless the subs are located outdoors and away from the ground, they can't reproduce it anyway. Inside a room, running them in mono instead is beneficial because they can be moved to wherever they create the least amount of resonance individually, and as a combination, make each other's response peaks and valleys less severe. As well, a "bass spaciousness" effect can be dialled in with the phase control if it's available on one of the subs (which is what happens when two widely spaced microphones pick up a low frequency source - same long wavelength, different phase between the two).
FYI... |
Please repost after you do your experiment. I'm interested in the results. Thinking of changing my Adire Rava with either 2 Velodyne DD or the new REL Britannia. Speakers Dynaudio S1.4, amp Plinius 102, Preamp Supratek, TT REGa Denon/ DL103 |
Hi Sailfishben,
Well, I have never personaly experienced two subwoofers setup receiveing separate stereo signals. But I've heard from people who say it makes a big difference.
I figured I'd buy couple of subwoofers to try it out and A/B test it w/ a single subwoofer, and then sell the extra subwoofer if there is no significant difference.
As for actually hooking up cables, my McIntosh C45 preamp is perfect. For stereo inputs, it can simultaneously provide THREE (two XLR balanced, one unbalanced) outputs. I connect the preamp to my amp via XLR connection and will use the other L & R XLR outputs for the subwoofers.
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My understanding is low frequency is basically non-directional so I'm wondering what the point is to use it in stereo? I know the sound stage created in my system has plenty of low end response and the low end seems to come from within the soundstage but certainly not from the corner of the room where the sub is actually located.
Wouldn't you have to run the speaker cables to the sub and then to the speakers, creating some long runs not to mention great expense for extra cabling? Although I wonder if you couldn't just use the r/l tape output (assuming they are not used already) letting the sub's crossover do its work on the signal. |
If money is relatively no object, go with the 12's. |
Hi Sailfishben,
A single DD15 or DD18 would be nice but I'm really interested in running two subs in stereo. When I say stereo, I don't mean two subs daisy chained to each other receiving the same LFE signal, but two subs receiving different left and right channel signals. |
I owned a DD-12 in a room 18x20x8 with one wall of sliding glass doors. Quite the sub but I replaced it with a DD-18. No comparison (nor should there be because of the cost). The 18" sub is just super with anything I use it for... movies or stereo listening. My thoughts are if your even thinking of two (2x the dollars) get the DD-18. Its increadible. Move it around a bit in the room if you can (have help!), find the sweet spot and then utilize the software to tune it to the room. This is one great subwoofer!
Better yet get two!
By the way... Velodyne has a pass through for a second sub built in to their DD series. |
All I can tell you is I have DD12 in a 18 x 24 x 9 high room and one is more than enough. I would say the 2 DD10s would be plenty. |
