Hornresp

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#10,501
David McBean said:
Not sure what version of WinISD you are using, but my old copy tells me that for a box volume of 283 litres, a tuning frequency of 28 Hz and a port area of 327 square cm, the vent length should be 28.5 cm, not 36.4 cm.

In Hornresp, for Ang = 2 x Pi, Vrc = 283, Ap = 327 and Lpt = 28.5, the Helmholtz resonance frequency is 28.0 Hz - exactly the same as for WinISD.
Click to expand...

Then the current version of WinISD is buggy.
 

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#10,503
BP1Fanatic said:
Have you tried modeling a negative flare tapped horn. I'm thinking you can get better performance within that same 283 liters. In their simplest form, a TH has 7 boards just like a BR. And, the T-TQWT will sound better!
Click to expand...

I have not tried. I believe my friend likes the visual impact of the woofer. He is building a three way with a 10 inch mid and a horn.

This is his first speaker project in 40 years, the previous being a RT 70/80 horn. He will not listen to me if I start talking about horns 🙂
 
#10,505
David McBean said:
Not sure what version of WinISD you are using, but my old copy tells me that for a box volume of 283 litres, a tuning frequency of 28 Hz and a port area of 327 square cm, the vent length should be 28.5 cm, not 36.4 cm.

In Hornresp, for Ang = 2 x Pi, Vrc = 283, Ap = 327 and Lpt = 28.5, the Helmholtz resonance frequency is 28.0 Hz - exactly the same as for WinISD.
Click to expand...

I simulated in Basta! as well. Same result as Hornresp, give or take a cm port length or a hertz in helmholz resonance.
 

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#10,511
more10 said:
If you implement offset driver with stubbed horn it can be done. I know you will not implement this but at least I have to try 😀
Click to expand...

Even though the amount of work involved to fully integrate the feature is massive, I decided nevertheless shortly after your original Post #10428 to proceed anyway, but not in the manner that you have suggested above. I have been working on the code for the past month, and still have some way to go. It will be possible to specify an enclosure with an offset driver together with either an offset port tube or an offset passive radiator, as shown in the attached example (for an offset port).
 

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#10,512
more10 said:
Changing end correction has no effect. You are right. The tube length shortens.
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Hi Mårten,

For a given enclosure volume and port tube cross-sectional area and length, changing from both ends flanged to one end flanged and the other end unflanged should increase the Helmholtz resonance frequency slightly. Changing from 4 tubes to one tube having the same total area will also affect the tuning frequency, due to the different loading conditions at the ends of the tube/s.

For a bass-reflex loudspeaker, Hornresp assumes a single port tube with the radiating end flanged and the internal end unflanged (this is different to how it is shown in the schematic diagram).

Kind regards,

David
 
#10,515
David McBean said:
Even though the amount of work involved to fully integrate the feature is massive, I decided nevertheless shortly after your original Post #10428 to proceed anyway, but not in the manner that you have suggested above. I have been working on the code for the past month, and still have some way to go. It will be possible to specify an enclosure with an offset driver together with either an offset port tube or an offset passive radiator, as shown in the attached example (for an offset port).
Click to expand...

Thank you so much David! This feature will be very useful. And the absorbent feature as well.

While you are at it, why not also allow a stub? 😀
 
#10,516
David McBean said:
Even though the amount of work involved to fully integrate the feature is massive, I decided nevertheless shortly after your original Post #10428 to proceed anyway, but not in the manner that you have suggested above. I have been working on the code for the past month, and still have some way to go. It will be possible to specify an enclosure with an offset driver together with either an offset port tube or an offset passive radiator, as shown in the attached example (for an offset port).
Click to expand...

Please delete this post David. I don't want to be remembered for being responsible for introducing proper simulation of BR into Hornresp :troll:
 
#10,517
David McBean said:
Hi Mårten,

For a given enclosure volume and port tube cross-sectional area and length, changing from both ends flanged to one end flanged and the other end unflanged should increase the Helmholtz resonance frequency slightly. Changing from 4 tubes to one tube having the same total area will also affect the tuning frequency, due to the different loading conditions at the ends of the tube/s.

For a bass-reflex loudspeaker, Hornresp assumes a single port tube with the radiating end flanged and the internal end unflanged (this is different to how it is shown in the schematic diagram).

Kind regards,

David
Click to expand...

Thanks David!

Going from 28 cm (one tube) to 36 cm (four tubes) is reasonable?
 
#10,520
Hi all,

need some help on how to model...

... a driver mounted in a sealed box, with a plate completely covering the face of the driver, and with a hole in the plate.
Plate thickness, or length of hole could range fro 1mm to 15mm.

Basically, like placing a driver in a MEH, but without any horn.

I'm thinking it might be worthwhile to understand how this simple test bed models, to learn what compression ratios, hole lengths, and T/S parameters work best...for eventual placement in a MEH.

Oh, and if there is a way to model changing the volume of space between the driver cone and the plate, that would be helpful too.

Thanks, mark
 
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