Velodyne Digital Drive Series subwoofer in stereo

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.

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.

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.

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.

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.