Hornresp

[weltersys]

Originally Posted by dirkwright

OK, here are the specs for the B&C DE10 1" compression driver. Is it possible to calculate T/S parameters from this data? I'm sorry I'm not expert enough to know how myself.

There is not enough information in the specifications that you posted that make it possible to determine the T/S parameters of the driver.

As John Sheerin stated, "Compression drivers have mechanical parameters just like any transducer", but to calculate T/S parameters would require more detail than voice coil size, impedance, inductance and magnetic strength.

[dirkwright]

Originally Posted by weltersys

There is not enough information in the specifications that you posted that make it possible to determine the T/S parameters of the driver.

As John Sheerin stated, "Compression drivers have mechanical parameters just like any transducer", but to calculate T/S parameters would require more detail than voice coil size, impedance, inductance and magnetic strength.

OK. I realize of course that one could purchase one of these and perform all the necessary measurements needed, but it would be better if the information were available before purchase. I have communicated with manufacturers to get more information, but still I don't think I could model a horn in Hornresp with the information I had. Heck, even many crossover design software does not support compression drivers, so I have found it tough to work with these things.

[David McBean]

Originally Posted by sannax

Well, my plan is to make a LeCleach horn for a JBL 2" driver.

Hi Chris,

All you really need to know are the exit area, exit angle and low frequency limit of the compression driver. If the exit angle is unknown then simply make an educated guess - it will be close enough.

Procedure:

1. Use the Hornresp Horn Segment Wizard to determine the required horn given inputs S1, F12, AT and Fta. For the example shown I have assumed a 2" diameter driver exit area, an exit half-angle of 5 degrees, and a required horn cutoff frequency of 250 hertz.

2. Calculate the results for Ang = 4.0 x Pi and Eg = 0. By setting Eg to zero, a constant velocity driver is assumed - it doesn't matter what driver parameter values are used.

3. Export the exact axisymmetric profile and use the data to construct the horn.

Kind regards,

David

[David McBean]

Originally Posted by dirkwright

I have communicated with manufacturers to get more information, but still I don't think I could model a horn in Hornresp with the information I had.

Hi dirkwright,

See my post above.

Kind regards,

David

[sannax]

Originally Posted by David McBean

Hi Chris,

All you really need to know are the exit area, exit angle and low frequency limit of the compression driver. If the exit angle is unknown then simply make an educated guess - it will be close enough.

Procedure:

1. Use the Hornresp Horn Segment Wizard to determine the required horn given inputs S1, F12, AT and Fta. For the example shown I have assumed a 2" diameter driver exit area, an exit half-angle of 5 degrees, and a required horn cutoff frequency of 250 hertz.

2. Calculate the results for Ang = 4.0 x Pi and Eg = 0. By setting Eg to zero, a constant velocity driver is assumed - it doesn't matter what driver parameter values are used.

3. Export the exact axisymmetric profile and use the data to construct the horn.

Kind regards,

David

Thank you very much, David!
I am going to use a JBL 2441. I think I have read somewhere that the exit angle is 10 degrees on most of the JBL drivers, so this shouldn't be to difficult.

[dirkwright]

Originally Posted by sannax

Thank you very much, David!
I am going to use a JBL 2441. I think I have read somewhere that the exit angle is 10 degrees on most of the JBL drivers, so this shouldn't be to difficult.

Yeah, I hoped it was pretty simple to design a horn using a compression driver. I think the difficult part comes in with the crossover. At least that's the case with me.

Maybe that's the next step for this software.

[sannax]

Passive crossovers with a compression driver is not the easiest task, I have read...that's why I go active, though not a walk in the park that either..

[Zero D]

@ David Mcbean

Hi, thanks i will reply to your posts soon.

[David McBean]

Originally Posted by dirkwright

I think the difficult part comes in with the crossover. Maybe that's the next step for this software.

Hi dirkwright,

Sorry, it's not going to happen :-).

My interest lies with the performance of the loudspeaker itself, not with how the signal is processed prior to reaching the driver.

Kind regards,

David

[dirkwright]

Originally Posted by David McBean

Hi dirkwright,

Sorry, it's not going to happen :-).

My interest lies with the performance of the loudspeaker itself, not with how the signal is processed prior to reaching the driver.

Kind regards,

David

OK, but without such a simulation it remains unclear (without lots of experimenting) how horn loudspeakers respond to passive crossovers. I'm not sure they respond in the same way that direct radiators respond, for example. I also don't think I can model horns in other kinds of software that do allow for the effects of a passive crossover and other filter elements.