Tozawa-Resonator : helps absorb 300Hz and below

[andy2]

Wonder if anyone had used this before. I found the info from Troels website. The actual info comes from a person from Japan who made one of the speakers from his designs.

He claims that these resonators do a better job of absorbing bass energy from 300hz and below.

http://www.troelsgravesen.dk/Ekta_Sugano.htm

[kelticwizard]

Andy:

Actually I think you meant these do a better job of absorbing frequencies of 300 Hz and above.

If so, that is very good news, because the usual polyester pillow stuffing materials are not particularly good below 500 Hz, so that is almost an octave lower.

If these work, I would think Transmission Line and Daline builders would make very good use of these.

[andy2]

Originally posted by kelticwizard
[B]Andy:

Actually I think you meant these do a better job of absorbing frequencies of 300 Hz and above.

I think these absorb 300Hz and below. At least that is what I understood from his writing.

[kelticwizard]

Andy:

Well, the main problem with stuffing is knocking out lower frequencies, not so much high ones, which are easy to absorb.

Here is the quote from the website you gave:

the energy of the sound is converted to thermal energy. However, it is difficult to absorb the bass of 300Hz or less in speaker box in this method. On the other hand, Resonator of absorbing sound (shut paper box or paper balloon) is especially
effective to 2KHz or less. The sound is converted into the vibration of paper.

My summary of the above would be: "This method is not that effective below 300 Hz, but it is very, very effective up to 2KHz".

Absorbing frequencies as low as 300 Hz is very good. That's somewhat lower than most normal stuffing.

[Tenson]

I have to say, I doubt their effectiveness. They are just too small, and I doubt their resonant frequency is anything like as low as 300Hz.

Along similar lines I think a 1-2mm thick sheet of soft steel, quite large (say down one of the speakers side panels) and glued to a piece of foam with flexible glue would work much better. That would stop the foam behind it absorbing the high frequencies so well, but you could always put another bit of absorber in front of it. The steel sheet would resonate and the foam behind it would damp it.

[Bill poster]

Tennis balls are very good apparently.