Here's the modeled impedance sweep:
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Hi carpenter,
Based on his link reference and expressed interest in the effect of horn truncation, I suspect that JoshK might be referring to the throat acoustical impedance rather than the system electrical impedance
.At S1 for Ang = 1.0 x Pi (quarter space):
Kind regards,
David
Attachments
Hi carpenter,
Based on his link reference and expressed interest in the effect of horn truncation, I suspect that JoshK might be referring to the throat acoustical impedance rather than the system electrical impedance
At S1 for Ang = 1.0 x Pi (quarter space):
Kind regards,
David
Thanks David. That was my second choice and the graphic is waiting if Josh requires it, but you beat me to the punch. I like your thought process and it certainly makes sense considering the bit with horn truncation. All I know is your software is the "cat's meow!" This is the third horn I've designed using Hornresp and it seems to be dead on. The first horn being my huge tapped horn, and the second horn being my folded bass horn. Wish you and computers could have been around 30 years ago
Hey Carpenter,
Once again I want to point out that if you sim the horn like an Exp(no extreme difference even if Exp. looks better) you will be able to leave the less relevant "constant directivity" and instead use directivity, on- or off-axis at choosen angle. I normally use 20 degrees for lower placed midhorns.
But David probably has better ideas and explanations.
Once again I want to point out that if you sim the horn like an Exp(no extreme difference even if Exp. looks better) you will be able to leave the less relevant "constant directivity" and instead use directivity, on- or off-axis at choosen angle. I normally use 20 degrees for lower placed midhorns.
But David probably has better ideas and explanations
.
Hey Carpenter,
Once again I want to point out that if you sim the horn like an Exp(no extreme difference even if Exp. looks better) you will be able to leave the less relevant "constant directivity" and instead use directivity, on- or off-axis at choosen angle. I normally use 20 degrees for lower placed midhorns.
But David probably has better ideas and explanations
Please explain (in detail) your process and I'll explore further.
Hi John,
Every now and then I come back to your wabepage! You have few excellent ideas viz your crescent shaped 60-400 hz horn. I do not use hornresp, no time to learn. I mainly lean towards you, great people, for DIY.
However, I want to do this project if you can help me. My friend can build the horn for me. My desired range is 100hz-600hz with 12'' driver in 1 pi. It also should be four sided like your 80hz horn. Compression chamber, we need one, no? Pls help if you have some time to spare.
Regards
Every now and then I come back to your wabepage! You have few excellent ideas viz your crescent shaped 60-400 hz horn. I do not use hornresp, no time to learn. I mainly lean towards you, great people, for DIY.
However, I want to do this project if you can help me. My friend can build the horn for me. My desired range is 100hz-600hz with 12'' driver in 1 pi. It also should be four sided like your 80hz horn. Compression chamber, we need one, no? Pls help if you have some time to spare.
Regards
Hey John,
Nothing special about this. I took At, Am and length from your plan and assumed you used exponential expansions for the two "folding" points.
Used Exp in Hornresp and instead of using the, for a mid or high, less useful "Constant Directivity", I went for "Tools/Directivity/Response/Off-axis(degrees)". Did it just to get a picture of what will happen.
Think it would be a good idea to initially compare SPL from your horn and the Exp to see that they aren´t to far from each other.
I tried this the other day and will repeat again with the "Tools/Directivity/Response/Off-axis(degrees)" and see what turns up.
Hi carpenter,
The Hornresp throat acoustical impedance chart shows the resistive (black trace) and reactive (red trace) loads presented to the driver by the horn - either directly or via a throat chamber. While it is not essential for a loudspeaker designer to have this information, it can be very useful in showing how the load changes as horn dimensions are altered. It is of course a fundamental input as far as the Hornresp simulation model is concerned.
In general, for a constant throat size and cutoff frequency, reducing the horn length will increase the magnitude of the ripples in the throat impedance, making the overall SPL response less smooth.
Each horn flare type has its own characteristic throat impedance "signature". It is often possible to identify the horn flare type simply by inspecting the corresponding throat impedance chart
.To fully appreciate the significance of throat acoustical impedance, and its place in horn loudspeaker theory, it is probably best to refer to one of the classic engineering texts such as Harry Olson’s "Acoustical Engineering" or Leo Beranek’s "Acoustics".
Kind regards,
David
Hi carpenter,
Don't forget that the Hornresp Directivity tools only work with single segment horns
.(That is why Lars is suggesting using a single-segment Exp approximation).
Kind regards,
David
Hi carpenter,
Don't forget that the Hornresp Directivity tools only work with single segment horns
(That is why Lars is suggesting using a single-segment Exp approximation).
Kind regards,
David
I just figured that out and am about to post a pic of the results. Thanks David.
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Hi carpenter,
At 400 Hz, the difference between 0 degrees and 20 degrees off-axis is only 1 dB - looking good
.Kind regards,
David
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Hi carpenter,
At 400 Hz, the difference between 0 degrees and 20 degrees off-axis is only 1 dB - looking good
Kind regards,
David
From the master, himself, thanks David. I can't believe what a fantastic addition this horn has made to my stereo system, and I owe it all to you -- and that's no bull.
Thanks John. I am very pleased that you were able to put Hornresp to good use
.I love your website - your work is very impressive indeed.
Kind regards,
David
Thanks John. I am very pleased that you were able to put Hornresp to good use
I love your website - your work is very impressive indeed.
Kind regards,
David
Thanks for that, David.- Status
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