What is Rms parameter? Suspension resistance?

Boscoe · 20th December 2010, 09:08 AM

I'm having a play with hornresp and it's asking this but I haven't seen this parameter in speaker data sheets before. How do I work it out from other parameters?

Flaesh · 20th December 2010, 09:28 AM

doubleclick at "Rms" and it will work..

David_Web · 20th December 2010, 09:33 AM

Press F1 when in hornresp and read through that. Especially page 9 regarding calculation of parameters.
I simply fill out Sd first then double click each field starting with Cms and ending with Bl (jump over Re as you need to enter it yourself as it cannot be calculated)
Then you double click on Sd and check the parameters it gives if they are close to the spec sheet.
Usually there will be deviation due to rounding in the spec sheet. (should still be small)
Or outright bogus data from the mfgr. I have also found mistakes where numbers where mistyped from a reputable mfgr.

Boscoe · 20th December 2010, 09:33 AM

Okay thanks.

speaker dave · 20th December 2010, 01:25 PM

To your original question. Rms is (are) the mechanical loss(es) of a driver. Mostly suspension related, such as viscous drag in the material. Some rubber surrounds have very high loss, foam usually low. Electrodynamic loss is here also, so aluminum voice coil formers will have lower Q. Forcing air through a cloth suspension is also an Rms contributor.

Rms is the resistance that determines Qms. (High mechanical drag gives low mechanical Q.)

David

20th December 2010, 09:08 AM	#1
Boscoe diyAudio Member Join Date: Feb 2010 Location: England	What is Rms parameter? Suspension resistance? I'm having a play with hornresp and it's asking this but I haven't seen this parameter in speaker data sheets before. How do I work it out from other parameters?

20th December 2010, 09:28 AM	#2
Flaesh diyAudio Member Join Date: Dec 2009 Location: Eburg	doubleclick at "Rms" and it will work.. __________________ flesh flash flush

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20th December 2010, 09:33 AM	#3
David_Web diyAudio Member Join Date: Sep 2008	Press F1 when in hornresp and read through that. Especially page 9 regarding calculation of parameters. I simply fill out Sd first then double click each field starting with Cms and ending with Bl (jump over Re as you need to enter it yourself as it cannot be calculated) Then you double click on Sd and check the parameters it gives if they are close to the spec sheet. Usually there will be deviation due to rounding in the spec sheet. (should still be small) Or outright bogus data from the mfgr. I have also found mistakes where numbers where mistyped from a reputable mfgr.

20th December 2010, 01:25 PM	#5
speaker dave diyAudio Member Join Date: Nov 2009 Location: Toronto	To your original question. Rms is (are) the mechanical loss(es) of a driver. Mostly suspension related, such as viscous drag in the material. Some rubber surrounds have very high loss, foam usually low. Electrodynamic loss is here also, so aluminum voice coil formers will have lower Q. Forcing air through a cloth suspension is also an Rms contributor. Rms is the resistance that determines Qms. (High mechanical drag gives low mechanical Q.) David

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