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?
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?
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.
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.
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 ...)
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.
MaVo, I asked for Earl's opinion on Audyssey. I didn't ask someone else to link Harman papers I already know. If you would have followed this thread from the beginning, then you would know that I'm pretty familiar with those.
If you feel the need to comment about me as a person then don't do it in public but send a PM. This thread is about multisub.
Here is a shot of my current system, both channels plus three subs, and the small dip at 9kHz might be a positional error, anyway...
This response is revealing, not having a strong signature. Some recordings sound a little thin and others sound a little heavy, however slightly more often they are heavy especially with male vocals.
Does my bass region have too much boost?
This response is revealing, not having a strong signature. Some recordings sound a little thin and others sound a little heavy, however slightly more often they are heavy especially with male vocals.
Does my bass region have too much boost?
Attachments
IF setup properly via Earl's approach, additional subs will never degrade response. At worst, you get a similar response plus better headroom. If the added sub causes a problem that isn't fixed by available amp phase/volume/XO adjustments, move it a couple feet (effectively a phase adjustment) and try again.
When done right, response will always (at some level of measurement) improve with each additional sub. Dr Geddes experience indicates that (IF you are getting plenty of clean output already), audible improvements are usually negligible after three or four (well-set up) subs.
Though I'm not opposed to it, digital signal processing introduces unnecessary variables to be distracted with. The essential adjustments (phase, output, XO) available on common plate amps will get 99% as good results in 99% of rooms.
Setup of even 2 or 3 subs by ear is very difficult for most listeners to do well. Real experts in the field measure for a reason: Sanity. If you do it by ear, you'll wind-up like those in the "cable-changers club" and never stop fiddling with the setup. Human brain and physiology is not wired for spatial averaging at bass frequencies.
Those that have the capabilty to measure, should!
--Mark
Thanks tubamark, now it falls in to place
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thanks again
Anyway, is it true that the schroeder frequency obviates any concern about stereo localisation issues, such as the stereotypical (no pun intended) concern about stereo needing to be maintained above 80Hz, for example? (apart from a little ambiguity for an octave or so around fs, of course)
...<long rant deleted>...
thanks again
Anyway, is it true that the schroeder frequency obviates any concern about stereo localisation issues, such as the stereotypical (no pun intended
) concern about stereo needing to be maintained above 80Hz, for example? (apart from a little ambiguity for an octave or so around fs, of course)I doubt that having 3 of 4 subs in a corner is "well set up" but, if I understood AllenB correctly, this is what he's trying to do.
The output needs to be EQ-ed to get a flatter frequency response (or whatever target curve you're looking for) at every listening position. Reducing seat-to-seat differences by using multiple subs doesn't solve the problem of non-flat frequency response. Audyssey is pretty good at this.
No, I currently have three subs in addition to the mains. One is in a corner, one is central on the front wall and one is on the side. I spent two days setting them up.
But you want to add a 4th sub to a tri-corner? Well, try and measure. I'd try placing it somewhere else, even off the ground.
By the way AllenB, if you want to show meaningful data, then switch off all smoothing and make sure the frequency resolution is about 1Hz. That kind of steady state data from all frequency sources playing at once is meaningful for about 150-200Hz and lower. Above the Schroeder frequency, only single speaker measurements are meaningful.