Multiple Small Subs - Geddes Approach

[AllenB]

I'm trying to reason how marginal is the difference between setting up by ear and using measurements so I can gauge how hard to try. I'm also curious about variable phase.

If I swap my corner sub and the one between the mains, I notice a sizeable difference either measured individually and together. They are different units but they have an almost identical response (SPL) and sensitivity. Each has nothing more than a 2nd order electrical low pass filter. The only difference, I guess, could be found in the phase plots.

My first concern is how much it matters which one I use in each location?

[MaVo]

I would allways do measurements, as what sounds good after a short listening doesnt necessarily sound as well after a longer time. And how much does the location matter? Well, you can see that with a measurement

You can get a measurement mic (behringer for example) and a usb connection with phantom power for relatively low money, compared to the amount of use they have.

[AllenB]

Thanks MaVo, I get much better results with my Behringer than with my previous mike. It's just that when I read the tutorials on how to do this it looks like you could do it without signal processing or all pass filtering. Now I wonder if it is necessary to do this.

[gedlee]

I would not expect much difference in your swap, but if you measure a difference then so be it. Choose the one that gives the best results. There is not much more to say.

[markus76]

Hi Earl

Audyssey now does multiple subs (2) too. Would like to hear your opinion on their optimization approach. You probably followed Chris Kyriakakis papers over the years.

Best, Markus

[MaVo]

If you want to skip allpass filters and just deal with a mono sub signal, try the harman approach (google "harman white paper" for the site).

[markus76]

MaVo, you obviously didn't follow this thread from the start, I did.

[gedlee]

Originally Posted by markus76

Hi Earl

Audyssey now does multiple subs (2) too. Would like to hear your opinion on their optimization approach. You probably followed Chris Kyriakakis papers over the years.

Best, Markus

No I have not read any papers by Chris. I only read JAES and then not very much. Its been a very long time since I've read anything that I didn't already know. In fact my last two publications in JAES were letters about papers that had no references at all to prior art. They were both completely described previously. At any rate I have no idea what Audyssey does, so I can't comment (but you know my opinion on the rest of the Audyssey technology, along with all the other "magic" electronic boxes. I would basically put them all in the same place ...)

[markus76]

S. Bharitkar and C. Kyriakakis, “Robustness of Spatial Average Equalization: A Statistical Reverberation Model Approach”, Journal of the Acoustical Society of America, 116(6), 3491-3497, (2004).
There're also some AES convention papers.

[MaVo]

Originally Posted by markus76

MaVo, you obviously didn't follow this thread from the start, I did.

So what?

My advice was just fine or do you really want to say Toole is wrong and his concepts dont work?

To quote someone famous who happens to also post here: "Markus, you are just too extreme for me at times."

You should think about your obsessive behaviour, it is unhealthy.