Hello friends,
Please help me understand what I am doing wrong. I have tried to learn the programs Hornresp and AKBAK by building simple models of horn speakers in both programs and then comparing the results. I have discussed the results with Mr. Chatgpt because I cannot get the comparison right. I do not really know what to expect in terms of similarity between the results. I am not very knowledgeable in electronics or theoretical audio technology but I still think I understand that the sound pressure curves and impedance curves should be quite similar for simple models with these two programs. Mr. Chatgpt has been very helpful I think but "he" has not managed to figure out what I am doing wrong.
I have placed an infinite baffle in the same plane as the horn mouth to get a 2 x pi radiation angle. The speaker element is this 15-inch element:
https://loudspeakerdatabase.com/BC/15DS115_8Ω
I think the impedance curves match quite well, at least the frequency of the first peak, but not quite the level (Hornresp: 4.4 Ohm@125Hz, AKABAK: 3.2 Ohm@128Hz). The second peak matches better in terms of level but worse in terms of frequency (Hornresp: 2.46 Ohm@284Hz, AKABAK: 2.2 Ohm@267Hz).
What bothers me the most is the difference in sound pressure for the two models. AKABAK has a first peak already at 54 Hz and sound pressure 74 dB. This peak does not exist in Hornresp which has its first peak at 125 Hz and 108 dB. The next peak in AKABAK is at 135 Hz and 68 dB. This does not match very well with Hornresp.
Please help me understand what I am doing wrong. I have tried to learn the programs Hornresp and AKBAK by building simple models of horn speakers in both programs and then comparing the results. I have discussed the results with Mr. Chatgpt because I cannot get the comparison right. I do not really know what to expect in terms of similarity between the results. I am not very knowledgeable in electronics or theoretical audio technology but I still think I understand that the sound pressure curves and impedance curves should be quite similar for simple models with these two programs. Mr. Chatgpt has been very helpful I think but "he" has not managed to figure out what I am doing wrong.
I have placed an infinite baffle in the same plane as the horn mouth to get a 2 x pi radiation angle. The speaker element is this 15-inch element:
https://loudspeakerdatabase.com/BC/15DS115_8Ω
I think the impedance curves match quite well, at least the frequency of the first peak, but not quite the level (Hornresp: 4.4 Ohm@125Hz, AKABAK: 3.2 Ohm@128Hz). The second peak matches better in terms of level but worse in terms of frequency (Hornresp: 2.46 Ohm@284Hz, AKABAK: 2.2 Ohm@267Hz).
What bothers me the most is the difference in sound pressure for the two models. AKABAK has a first peak already at 54 Hz and sound pressure 74 dB. This peak does not exist in Hornresp which has its first peak at 125 Hz and 108 dB. The next peak in AKABAK is at 135 Hz and 68 dB. This does not match very well with Hornresp.
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Ramsten,
The Hornresp impedance and frequency response look like what one would expect from a short mid-bass horn using the BC15DS115-8.
I'm not familiar with AKABAK program, but from what I've seen, normally it should match Hornresp pretty closely if the inputs are correct.
There might be a difference between Hornresp "Acoustic Power" the total acoustic energy output of the horn, which does not take directivity into account, and AKABAK's "(dB) Level, sound pressure", but that should only affect the upper response.
No idea why the AKABAK impedance would come in so much lower than the driver's Re, or why the frequency response would drop nearly an octave compared to the impedance, but there is no way a 751mm long horn would have an Fc ~54Hz, so something is definitely wrong.
Art
The Hornresp impedance and frequency response look like what one would expect from a short mid-bass horn using the BC15DS115-8.
I'm not familiar with AKABAK program, but from what I've seen, normally it should match Hornresp pretty closely if the inputs are correct.
There might be a difference between Hornresp "Acoustic Power" the total acoustic energy output of the horn, which does not take directivity into account, and AKABAK's "(dB) Level, sound pressure", but that should only affect the upper response.
No idea why the AKABAK impedance would come in so much lower than the driver's Re, or why the frequency response would drop nearly an octave compared to the impedance, but there is no way a 751mm long horn would have an Fc ~54Hz, so something is definitely wrong.
Art