I was recently reading through some of the Aperion tutorials on setting up my system, looking to learn ways to optimize it; when I came across the tutorial on crossovers.  If I understood it correctly, the perceived volumn is affected by whether the sound waves from the different drivers arrive at your ears in phase or out of phase or somewhere in between.  This reminded me of a physics lesson where two waves of identical frequency 180 degrees out of phase can cancel each other out and in effect produce silence.  It also got me to thinking about the different objects and materials in my HT room that reflect and absorb the various frequencies to a different degree.  It seems to me that this would create a difference in the volumns of the individual frequency ranges that would affect the perception of sound.  After setting the proper speaker distances and using the SPL meter to equalize the individual speaker volumns, I noticed a big improvement in the sound stage over tuning by ear.  My question is, how do I equalize the volumns of the individual frequency ranges to offset my room dynamics?  Can I use the SPL or do I need something else?  I know my AVR has a built in equalizer (Onkyo 876) but I haven't found a way to test individual frequency volumns so that I can accurately adjust them.  I have 5T's and a 5C with a 10D Bravus sub and will soon be adding 5B's for surrounds.  Thank you for your help. 

“I was recently reading through some of the Aperion tutorials on setting up my system, looking to learn ways to optimize it; when I came across the tutorial on crossovers.  If I understood it correctly, the perceived volumn is affected by whether the sound waves from the different drivers arrive at your ears in phase or out of phase or somewhere in between.  This reminded me of a physics lesson where two waves of identical frequency 180 degrees out of phase can cancel each other out and in effect produce silence.  It also got me to thinking about the different objects and materials in my HT room that reflect and absorb the various frequencies to a different degree.  It seems to me that this would create a difference in the volumns of the individual frequency ranges that would affect the perception of sound.  After setting the proper speaker distances and using the SPL meter to equalize the individual speaker volumns, I noticed a big improvement in the sound stage over tuning by ear.  My question is, how do I equalize the volumns of the individual frequency ranges to offset my room dynamics?  Can I use the SPL or do I need something else?  I know my AVR has a built in equalizer (Onkyo 876) but I haven't found a way to test individual frequency volumns so that I can accurately adjust them.  I have 5T's and a 5C with a 10D Bravus sub and will soon be adding 5B's for surrounds.  Thank you for your help”

 

 

 

 

This may be true if you are adding the sum of two sinusoidal signals and electronically reading the output of an Operational Amplifier with the same signal applied to both Inverting and Non-Inverting inputs, simulating 180 degrees out of phase. The output should be null.

 

But with speakers 180 degrees out of phase, sound will be output by each speaker. You will notice the difference most between in phase and out of phase speakers with bass content. Out of phase will produce less noticeable bass and the sound stage in a stereo setup will probably not sound good.

 

I really don’t think you can optimize for each frequency range other than adjusting to your own tastes. Once you have balanced the SPL levels for each speaker relative to your listening position, you can play with the built in equalizer to attain the sound you want from each channel.

 

I have an Onkyo 805 and Audyssey did a good job of setting the basics. I switch between Audyssey and Manual and get different results sonically with each. It is your choice. The test tone emitted by the Audyssey setup outputs a complex tone to adjust the speakers. I think that after you have balanced SPL with your speakers, the only thing left to do is experiment with various settings.

 

It pays to experiment a bit.

 

Jack

Hi DD, wow--sounds like you're getting deep in it! I would agree with Jack and experiment a bit; but I would also urge you to not forget about more "natural" ways of controlling your room's acoustics, a la properly placed furnishings and the like. No doubt your room's acoustic properties are just as important--perhaps even more so--than any other sound quality determining factors regarding your system. And taking the time to control absorption, diffusion, and reflections without electrical correction can pay huge sonic dividends.

It's been my experience that most quality loudspeakers are designed to offer exceptionally natural sound and frequency response in a non-EQ'd room--i.e. rooms that have normal furnishings, drapes etc. to control too many unwanted reflections (yes, there is such a thing as desirable reflections, but let's not go there yet). A great source for information on how to control absorption, diffusion, and reflections would be the Rives Audio resource page here: http://www.rivesaudio.com/resources/links/frame.html). Only once you’ve exhausted your options for natural acoustical correction would I recommend using electrical correction; most of our customers report getting more natural, lifelike sound in a properly treated room with Audyssey off, but your mileage may vary. Looks like there’s some good info above on Audyssey so I won’t go into that here; but keep in mind that electrical correction can only ever be an after the fact band-aid solution of sorts. Hope this helps!

 

Happy Listening,

Oliver

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Oliver Amnuayphol
Home Theater/Audio Guru
Aperion Audio

Thank you Jack for your input.  I wasn't sure if there was a way to adjust the frequency ranges other than by experimenting with the equalizer settings.

Thank you Oliver for your response.  I went to the link you posted and found some articles that addressed what I was trying to describe concerning frequency response (including graphs).  I also found a good desription of how to maximize the sound stage that was clear even to a newbie like me.  Very interesting site.