Mitchibo

Mitchibo

Audioholic
These are some of my first measurements in my room. I don't know if this is good, bad, or what. Feel free to comment.


First graph: Left and Right mains with Audyssey. Second graph: Subs and left/right mains with Audyssey. The subs have a mini DSP with a high and low pass filter on them, hence the slopes. All four subs running from a single output measured as a group. On the second graph I probably forgot to set the sub trims back to zero.

 
William Lemmerhirt

William Lemmerhirt

Audioholic Overlord
Not here on Tapatalk either. I'll try the web version...
Nope!
 
Mitchibo

Mitchibo

Audioholic
left and right mains with audyssey.jpg
subs and left,right mains with audyssey.jpg
The first graphic is mains plus Audyssey. The second is mains plus subs plus Audyssey
 
Last edited:
P

PENG

Audioholic Slumlord
Something is not right, you mentioned minidsp high and low pass, did you mean you want to filter out the low frequencies. If so, why?
 
TheWarrior

TheWarrior

Audioholic Ninja
The room is in control of bass. You can leave it to the magic of Audyssey and hope it's results are satisfactory (which your measurements, are not) or get out a tape measure and start measuring ALL of the parallel boundaries of your room.

1131(feet per sec) / measurement (in feet) = Room Mode - which will measure as a peak or null at the LP depending on it's +/- phase cycle - subwoofers are pressure sources, placement is everything

Frequency + Amplitude + Q = DSP Filter.

(center of peak or null) + (dB increase/decrease to reach relative level) + (bandwidth of resonance measured in hz) = DSP Filter

Those 3 parameters allow you to create a DSP filter to overcome the natural response of producing frequencies that are larger than the dimensions of your room. (20 hz = 56.5 feet for example)

Measurements MUST be taken as 1/24 octave so that nothing is masked. Windows and doors allow flex in boundaries which will lower the measured resonance frequency from predicted. But when you know which boundaries are influencing a frequency, the orientation of subwoofer(s) at that boundary allows you to constructively or destructively drive the standing waves.

If you're really serious and want to learn more, 'Sound Reproduction' by Floyd Toole is the textbook on the subject. He just released the 3rd edition so be mindful which one you order. This is a lifetime of research backed by double blind testing with only minimal mathematics being presented, such as what I've suggested.
 
Pogre

Pogre

Audioholic Slumlord
The room is in control of bass. You can leave it to the magic of Audyssey and hope it's results are satisfactory (which your measurements, are not) or get out a tape measure and start measuring ALL of the parallel boundaries of your room.

1131(feet per sec) / measurement (in feet) = Room Mode - which will measure as a peak or null at the LP depending on it's +/- phase cycle - subwoofers are pressure sources, placement is everything

Frequency + Amplitude + Q = DSP Filter.

(center of peak or null) + (dB increase/decrease to reach relative level) + (bandwidth of resonance measured in hz) = DSP Filter

Those 3 parameters allow you to create a DSP filter to overcome the natural response of producing frequencies that are larger than the dimensions of your room. (20 hz = 56.5 feet for example)

Measurements MUST be taken as 1/24 octave so that nothing is masked. Windows and doors allow flex in boundaries which will lower the measured resonance frequency from predicted. But when you know which boundaries are influencing a frequency, the orientation of subwoofer(s) at that boundary allows you to constructively or destructively drive the standing waves.

If you're really serious and want to learn more, 'Sound Reproduction' by Floyd Toole is the textbook on the subject. He just released the 3rd edition so be mindful which one you order. This is a lifetime of research backed by double blind testing with only minimal mathematics being presented, such as what I've suggested.
You just copy pasted this from your post in my thread! lol
 
Pogre

Pogre

Audioholic Slumlord
Have you tried taking several measurements placing the mic in the same pattern you do when running Audyssey, then average them? From what I see in those measurements you're good down to about 50hz?
 
Mitchibo

Mitchibo

Audioholic
Something is not right, you mentioned minidsp high and low pass, did you mean you want to filter out the low frequencies. If so, why?
I put a low and high pass filter in the mini to get rid of the 10 to 25 hz because these subs are not rated for those frequencies. It also slopes off after 80 thereby clipping off those useless responses. The overall profit is bass that seems much more punchy. I'm just following in the knowledge of others with satisfactory results in the end. At least that's what I tell myself.
 
Mitchibo

Mitchibo

Audioholic
Have you tried taking several measurements placing the mic in the same pattern you do when running Audyssey, then average them? From what I see in those measurements you're good down to about 50hz?

No, I have not taken REW measurements in the order suggested. I only have a single LP so I haven't bothered but now I'm curious to try that.

My intent is to show the yield of what my room is with the setup. I just got a handle on the process of measuring. It's fascinating stuff. I'm not sure if I can improve on Audyssey but my main concern is what can be done on the subs with the mini. These are the first "constructive" graphs worth publishing. Just step #1.
 
Pogre

Pogre

Audioholic Slumlord
No, I have not taken REW measurements in the order suggested. I only have a single LP so I haven't bothered but now I'm curious to try that.

My intent is to show the yield of what my room is with the setup. I just got a handle on the process of measuring. It's fascinating stuff. I'm not sure if I can improve on Audyssey but my main concern is what can be done on the subs with the mini. These are the first "constructive" graphs worth publishing. Just step #1.
You don't have much to tweak, really. It looks like there's not a lot happening below 50hz. You say you're filtering low frequencies too? Something doesn't look right. It looks like you don't have subs at all.
 
P

PENG

Audioholic Slumlord
I put a low and high pass filter in the mini to get rid of the 10 to 25 hz because these subs are not rated for those frequencies. It also slopes off after 80 thereby clipping off those useless responses. The overall profit is bass that seems much more punchy. I'm just following in the knowledge of others with satisfactory results in the end. At least that's what I tell myself.
I don't have the mini yet so I am not familiar with the terminologies they use. By "low and high pass", I assume they mean "Band pass", that to me should be the right term, but anyway, I'll learn more about it when I get mine.
 
Mitchibo

Mitchibo

Audioholic
subs with and with out audyssey.jpg






Red line is subs w/mini and no Audyssey, blue line is subs w/mini and WITH Audyssey
 
Mitchibo

Mitchibo

Audioholic
I don't have the mini yet so I am not familiar with the terminologies they use. By "low and high pass", I assume they mean "Band pass", that to me should be the right term, but anyway, I'll learn more about it when I get mine.
Yes Peng, same idea just different terms.
 
panteragstk

panteragstk

Audioholic Warlord
If I'm reading your sig correctly it appears that you have 8 klipsch subs? Is that all in one room? And with that many your output above appears as above? Something isn't right. What happens if you turn OFF the high pass and measure?
 
Mitchibo

Mitchibo

Audioholic
If I'm reading your sig correctly it appears that you have 8 klipsch subs? Is that all in one room? And with that many your output above appears as above? Something isn't right. What happens if you turn OFF the high pass and measure?
Not eight rather four subs. Two in the front 8ft apart, two in the rear cornered, 12 ft apart in room 14 ft between the fronts and backs.

I put the high pass on it just to attenuate fq after 80 hz. Are you suggesting I should extend the curve more for a gentler slope? With both filters (high and low-pass) obviously the graph is very bell shaped but that's normal right? Since subs are not full ranger and mine are rated down to 24 hz should I expect and shoot for a flatter curve? I don't have anything to compare the graph to therefore I don't know if what Ive presented is good, bad, or ugly.
 

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