simulating variovent with MJK sheets?

Henkjan · 24th March 2008, 05:06 PM

I am designing a pair of speakers (using the FR125) for my 11 year old daughter. since her wish is that they should not be too large (yes, this sh*t starts already at a young age), I thought of making a aperiodically damped (aka variovent, aka controlled leakage, etc) CB. (I first proposed the miniOnkens, but even these were considered too large)

a thought came in my head to use MJK's mathcad sheets for this, using the BR sheet and then "applying" damping material in the port to simulate the variovent.

anyone has ever done this? @MJK: do you expect this to give good results? and related: in your sheets you give 1 lb/ft³ as max damping material density, why's that?

gurley123 · 24th March 2008, 06:46 PM

I'm not sure about simulating aperiodic vents. I've yet to use the mathcad sheets. However, according to the last few posts by Planet 10, many are now perfering the 4.5 liter aperiodic cabs for the FR125. These are a bit smaller than the MiniOnkens.

Maybe she'll like those?

Henkjan · 25th March 2008, 07:31 PM

that should give a starting point as well as a fall-back position... thanks.

I'll start the design on the speakers in a week or so (want to finish a pair of table-top TLs first) so if anyine can add some thoughts on this, please do so... and if I'm the 1st to try this, I'll report back here about the results

Henkjan · 25th March 2008, 07:33 PM

Quote:

Originally posted by gurley123
Maybe she'll like those?

the design is more or less agreed apon, it will not be the average sqare box....

gurley123 · 25th March 2008, 07:42 PM

I'm glad it worked out for you.

11 yrs old and already getting a good set of speakers. That's too cool. My little sister is 17 and I don't think she's heard a decent stereo yet (we never lived in the same house, or else she would have.)

I'm toying with the idea of making her a cool little mini system with some cheap fullrangers and a tripath amp. Looks like it could be fun.

Henkjan · 25th March 2008, 08:24 PM

well, I have to admit it was the special design I have in mind and the FR125's good looks that made here give in (I had been trying to build a pair of decent speakers for her for a long time already, but she's not realy into music yet), but I'm sure she'll appreciate the result when they are ready

maxro · 26th March 2008, 05:19 AM

Quote:

Originally posted by Henkjan

a thought came in my head to use MJK's mathcad sheets for this, using the BR sheet and then "applying" damping material in the port to simulate the variovent.

anyone has ever done this? @MJK: do you expect this to give good results? and related: in your sheets you give 1 lb/ft³ as max damping material density, why's that?

The 'ported box" work sheet allows densities over 1lb/ft3 in the port section. IIRC, Planet10 had mentioned some reservations about using this method for aperiodic simulation, but I think it to be the best solution thus far. I guess the question is: what is the stuffing density of a Variovent?

Scottmoose · 26th March 2008, 08:57 AM

Depends on what's required. You can sim aperiodic well enough using Martin's sheets.

Henkjan · 26th March 2008, 09:27 PM

OK, let's fire up the quattro uh mathcad

Scottmoose · 26th March 2008, 11:28 PM

You've been watching Ashes to Ashes haven't you?

24th March 2008, 05:06 PM	#1
Henkjan diyAudio Member Join Date: Jan 2006 Location: Berkel en Rodenrijs	simulating variovent with MJK sheets? I am designing a pair of speakers (using the FR125) for my 11 year old daughter. since her wish is that they should not be too large (yes, this sh*t starts already at a young age), I thought of making a aperiodically damped (aka variovent, aka controlled leakage, etc) CB. (I first proposed the miniOnkens, but even these were considered too large) a thought came in my head to use MJK's mathcad sheets for this, using the BR sheet and then "applying" damping material in the port to simulate the variovent. anyone has ever done this? @MJK: do you expect this to give good results? and related: in your sheets you give 1 lb/ft³ as max damping material density, why's that?

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24th March 2008, 06:46 PM	#2
gurley123 diyAudio Member Join Date: Oct 2007	I'm not sure about simulating aperiodic vents. I've yet to use the mathcad sheets. However, according to the last few posts by Planet 10, many are now perfering the 4.5 liter aperiodic cabs for the FR125. These are a bit smaller than the MiniOnkens. Maybe she'll like those?

25th March 2008, 07:31 PM	#3
Henkjan diyAudio Member Join Date: Jan 2006 Location: Berkel en Rodenrijs	that should give a starting point as well as a fall-back position... thanks. I'll start the design on the speakers in a week or so (want to finish a pair of table-top TLs first) so if anyine can add some thoughts on this, please do so... and if I'm the 1st to try this, I'll report back here about the results

25th March 2008, 07:42 PM	#5
gurley123 diyAudio Member Join Date: Oct 2007	I'm glad it worked out for you. 11 yrs old and already getting a good set of speakers. That's too cool. My little sister is 17 and I don't think she's heard a decent stereo yet (we never lived in the same house, or else she would have.) I'm toying with the idea of making her a cool little mini system with some cheap fullrangers and a tripath amp. Looks like it could be fun.

25th March 2008, 08:24 PM	#6
Henkjan diyAudio Member Join Date: Jan 2006 Location: Berkel en Rodenrijs	well, I have to admit it was the special design I have in mind and the FR125's good looks that made here give in (I had been trying to build a pair of decent speakers for her for a long time already, but she's not realy into music yet), but I'm sure she'll appreciate the result when they are ready

26th March 2008, 08:57 AM	#8
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Depends on what's required. You can sim aperiodic well enough using Martin's sheets.

26th March 2008, 09:27 PM	#9
Henkjan diyAudio Member Join Date: Jan 2006 Location: Berkel en Rodenrijs	OK, let's fire up the quattro uh mathcad

26th March 2008, 11:28 PM	#10
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	You've been watching Ashes to Ashes haven't you?