Let me try again. I had 2 copies of the file, one corrupt, probably the one i zipped because i couldn’t open it either. Here is a pdf of the other one.
dave
Dave,
That's it indeed! Thanks for finding and sharing that, I feared it was lost.
Eric
Let me try again. I had 2 copies of the file, one corrupt, probably the one i zipped because i couldn’t open it either. Here is a pdf of the other one.
dave
bass reflex design using the Mark Audio Alpair 10M.3 driver, in a 27.5 liter enclosure
above about 1000 Hz
Way too big AFAIC. The biggest Mar-Ken for these is 13 litres.
You should not be paying any attention to anything over a few hundred Hz. You are modeling the LF performance.
You should not be paying any attention to anything over a few hundred Hz.
I couldn't see any any air leaks or obvious gaps during the screwing procedure.
Way too big AFAIC. The biggest Mar-Ken for these is 13 litres.
Didn't realise it was that critical.
Hmmm. Interesting. Didn't realise it was that critical.
In the Hornresp result the power falls off quickly above about 1000 Hz, while the LATL result is generally flat (excluding the spikes) out to over 10,000 Hz.
I also tried identical Sealed Box and MLTL alignments with the two programs and saw the same difference in each one.
For your given bass reflex example, the results are different at higher frequencies because Hornresp is showing the power response whereas LATL is showing the pressure response (which means that LATL must be making some assumptions on directivity, and including them in the simulation model).
The initial peak in the response is lower in Hornresp because system losses have been taken into account (QL = 7).
For your sealed box example, try using the Directivity tool in Hornresp to calculate the on-axis pressure response, and then compare that result to LATL instead.
Is this difference also just due to the fact that LATL result is pressure, and Hornresp is power, or is there more to it than that?
'Been there, done' that and amidst much nay-saying, others have learned the hard way too.'Those who don't learn from history are doomed to repeat it'.
Hi Eric,
Power and pressure response results are normally reasonably close at the lower frequencies, where "beaming" due to directivity is not a significant factor. The difference you are seeing below about 300 Hz is probably due to the Hornresp simulation having a specified acoustic path length of 100 cm. (It is difficult to know for sure without seeing the inputs you are using, but I suspect that LATL assumes a zero path length). Do the results look more similar perhaps, if the Hornresp path length is set to 0 cm?
Kind regards,
David
Hmm, looks like one of my HR sims done by setting the path length 1/2 the distance between the driver/port to emulate ~what we hear at a seated distance, so setting to zero should put the peaks/dips ~at the same frequencies, though from very dim memory the LA's TH sims were inverted, so at this point trust HR over LA is what I'd do.
GM