Very interesting results DorinD. Suggest you measure with 1 second window/measuring length. Then 1/T is 1 Hz and effects are more easy to see.
In the papers no load short circuit gives only 50% absorption at best, so i am not supprised 2*15" only shows 1 dB improvement in real life. Think up to 90% absorption with R, RC or RLC.
@GedLee: We would all like an reference listening room with damped walls, instead of an 8 inch with box in the corner. Remember the first paper deals with noise damping in domnestic rooms in general. (Traffic, airplane noise). Most people can't affort full treatment, so inexpensive and compact solutions for noise suppression are attractive.
That they also works to flatten the room responce is a bonus.
As you say many rooms has few resonanses at low freq. So damping those, if they are annoying, is feasible with this methode.
The dampers can even be integrated into other furniture.
In the papers no load short circuit gives only 50% absorption at best, so i am not supprised 2*15" only shows 1 dB improvement in real life. Think up to 90% absorption with R, RC or RLC.
@GedLee: We would all like an reference listening room with damped walls, instead of an 8 inch with box in the corner. Remember the first paper deals with noise damping in domnestic rooms in general. (Traffic, airplane noise). Most people can't affort full treatment, so inexpensive and compact solutions for noise suppression are attractive.
That they also works to flatten the room responce is a bonus.
As you say many rooms has few resonanses at low freq. So damping those, if they are annoying, is feasible with this methode.
The dampers can even be integrated into other furniture.
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scottjopplin, to achieve good bass response i have done as you have.15-28Hz is covered by IB (4*15" in the wall between listening room and garage) from 28Hz to 150Hz i have dipole subwofers in stereo each having 2*15" long throw. From 150Hz and up to 20kHz is ESL63. On top of that i have done a test with RePhase (thanks rajapruk for your wisit and guidance) and that was interesting! time aligning in the bass is important!
RePhase is using both IIR and FIR as I understand.
rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
What do you mean by this? I am having trouble putting together what you might have done and how.
Well i have dipole woofers and electrostatics.
To make them play in phase at the crossower point i have an all pass filter. This filter makes a phase shift of around 5 turns. or approx 1800 degrees between 20 and 200 Hz.
Addition to that the infra bass system is located physically 7meters away from the dipole woofer (layout of the listening room and my garage infra subwoofer 15-27Hz).With digital FIR filtering and delay the soundstage is wery much improved, even thoug the frequency responce is quite the same. It´s just a complete new system. The bass is much more firm and precise. I´m out of word actually. rePhase is just magic!
To make them play in phase at the crossower point i have an all pass filter. This filter makes a phase shift of around 5 turns. or approx 1800 degrees between 20 and 200 Hz.
Addition to that the infra bass system is located physically 7meters away from the dipole woofer (layout of the listening room and my garage infra subwoofer 15-27Hz).With digital FIR filtering and delay the soundstage is wery much improved, even thoug the frequency responce is quite the same. It´s just a complete new system. The bass is much more firm and precise. I´m out of word actually. rePhase is just magic!
He,he
The article in post#50 shows 10dB at best. I think that is a good result for such a cheap solution if you have truble in shallow frequency bands because of room dimentions.
But, not a solution that solves all problems in all roms
Hi esl 63,
I so agree, rePhase is fantastic...many thanks to POS !
Curious, why did you need so many turns of phase shift?
He,he
The article in post#50 shows 10dB at best. I think that is a good result for such a cheap solution if you have truble in shallow frequency bands because of room dimentions.
But, not a solution that solves all problems in all roms
You can't compare an active absorber with a passive one. All I have seen data for in this thread is a passive one, which has not shown much effect at all. Active would be very effective, but a completely different animal.
So let me get this straight: you have a sub that's 7 meters away from the dipole mains and crossed over at 200 Hz? Or 27 Hz?
Based on my experience, what you are saying just doesn't make sense, except that a sub 7 meters away from the mains is a very very bad idea, so maybe rePhase does help this extremely bad situation. But for the most part I have not found phase or delay to be meaningful in a rooms modal region.
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