The speaker design software depends on VAS and Qts only when calculating the cabinet volume (ported).
But, though the VAS and Qts are accurate,
when I applied the calculated volume,
the results were not always the best in my ear.
I could get better result when applied bigger or smaller volume than the calculated result.
For example (with ported) ;
In case of Audiotechnology C-Quenze 18H52,
though the calculated volume is under 11 liters based on both the manufacturer's spec. and the self measurement,
when I applied 18H in the 11 liters cabinet, the bass was not so good to hear.
But when I increase the volume upto 16 liters, the bass was much better.
Likewise, a local speaker manufacturer applied over 30 liters in 18H.
In case of Scanspeak 18W/8531G, the result is better when I applied smaller volume than calculated one.
Indeed, are there any efficient methods to find the optimun cabinet volume ?
Do I have no choice but to apply several volumes randomly like a Don Quixote ?
But, though the VAS and Qts are accurate,
when I applied the calculated volume,
the results were not always the best in my ear.
I could get better result when applied bigger or smaller volume than the calculated result.
For example (with ported) ;
In case of Audiotechnology C-Quenze 18H52,
though the calculated volume is under 11 liters based on both the manufacturer's spec. and the self measurement,
when I applied 18H in the 11 liters cabinet, the bass was not so good to hear.
But when I increase the volume upto 16 liters, the bass was much better.
Likewise, a local speaker manufacturer applied over 30 liters in 18H.
In case of Scanspeak 18W/8531G, the result is better when I applied smaller volume than calculated one.
Indeed, are there any efficient methods to find the optimun cabinet volume ?
Do I have no choice but to apply several volumes randomly like a Don Quixote ?
afaik, you have to see what is best empirically - cut and try based on the simulations... among the things that change the results are your ears, the room, the placement in the room, and height above the floor. Also your amplifier, it's damping factor and some other things as well... not to mention what you put inside that speaker box, and what the walls of the box are doing.
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Based on the simulations of room, placement, height of floor...
It is impossible without a device that can simulate the result with the factors you mentioned.
Which device can do it ?
You might be like me, you don't like the sound of optimum alignment. It makes bass be as loud and low and flat as possible for given driver specs. It is good for dance music, but not much else, imo. I think you like it when tuned away from optimum because you reduce that unmusical punch by detuning the port efficiency. All simulator software defaults to this "optimum" computation. So if you prefer a different sound, you have to tweak it manually. But you have to understand what you're doing, or get lucky to know how to tweak. Don't ask me, I gave up after building 6 terrible sounding boxes. The exercise proved to me me that I prefer the sound of sealed boxes, I don't like group delay of ports. Then I discovered Linkwitz transform so I don't even think about reflex anymore. Of course, a truly great reflex box CAN be done, but it is not from a free box simulator on your first try.
Funny though, no two (internet) formulas for computing optimal bass reflex volume and port for given driver ever say the same answer. Use simulators with a grain of salt, as a starting place for tweaking by ear, or by sacred knowledge of reflex port voodoo magic.
I have found that pointing the ports out the rear sounds better to me. I think it prevents the direct sound from being mucked up by group delay from the port. But there are some excellent sounding commercial speakers with ports on the front, so don't believe anything you read on the internet. 😱
Funny though, no two (internet) formulas for computing optimal bass reflex volume and port for given driver ever say the same answer. Use simulators with a grain of salt, as a starting place for tweaking by ear, or by sacred knowledge of reflex port voodoo magic.
I have found that pointing the ports out the rear sounds better to me. I think it prevents the direct sound from being mucked up by group delay from the port. But there are some excellent sounding commercial speakers with ports on the front, so don't believe anything you read on the internet. 😱
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Proved one more time. 🙂
The devil's in the details. (Re-)Check carefully when something is not working and learn... from experience (I would say.) Saying only that it didn't work is not enough, one speaker is described but the second was not (for the alignment).
To model the room and speaker you (members) need to go to room modeler not WinISD. This softwares only give a fair chance of it to work, for most cases. Many times the question after an OP describes his speakers is amp? room size? and likes/dislikes? to mention just a few.
Then (you are not making a sub/woofer as is not the case) so the alignments members are using in their speakers are in close relation to BS (size of baffle) and crossover used, so that no box software can give any legitimate answer, that's so flawed...🙂
Looking at the parameters for 18H52 and allowing for the usual losses,the internal enclosure volume after allowing for solid parts should be 26.9 litres.This is a simple calculation using the manufacturers specifications and not from software.
I don't know how you came to 11 lit as an optimum for the 18H52. I am
happy to play around with this free spreadsheet and I have full confidence in it.
Loudspeaker Design Software
Simple formulas are not enough when it comes to finding a solid solution.
For your 18H52 driver I get these results which confirm your appreciaton of
better bass performance.
Attachments
According to the 18H52 of www.audiotechnology.dk, Qts is 0.32 and VAS is 28.5 liters.
I use Bassbox Pro software, and the calculated cabinet volume is 10.29 liters.
WinISD will show a bit larger volume, 13 liters or something.
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