Well, PK's last sim is only ~1.846 ft^3/52.273 L net, so there's room to 'burn' ergo if LF extension is more important than peak SPL and/or flattest 2pi response, then tuning down to 16 Hz seems doable based on a little fiddling with HornResp's Loudspeaker Wizard.
GM
GM
Pano, could you be more specific about your needs ?
What efficiency for the woofer ?
What bandwidth ?
What fullranger above ?
If it's an efficient and fast fullranger with big magnet, you should rather look in the professional speakers. Peerless SLS and alike would be definitely too slow.
My sugestion is
www.eminence.com/pdf/Basslite_S2010.pdf
It has the lowest fs of all professional, efficient 10"s that I know.
Look at Troels's DTQWT to check what can be done with them. Troels uses very similar Deltalite 2510,
What efficiency for the woofer ?
What bandwidth ?
What fullranger above ?
If it's an efficient and fast fullranger with big magnet, you should rather look in the professional speakers. Peerless SLS and alike would be definitely too slow.
My sugestion is
www.eminence.com/pdf/Basslite_S2010.pdf
It has the lowest fs of all professional, efficient 10"s that I know.
Look at Troels's DTQWT to check what can be done with them. Troels uses very similar Deltalite 2510,
Hmmmmm...?
For my last sim I very carefully set up the box size to make its gross volume be exactly 2.5 ft3 (12" x 12" x 30"), and then I calculated the actual net volume in the a single-fold line within it that I modeled to be 2.3 ft3, not 1.846 as you state? In any event, if Pano now is okay with a much bigger box, then there would be a whole more in general to play with.
Paul
For my last sim I very carefully set up the box size to make its gross volume be exactly 2.5 ft3 (12" x 12" x 30"), and then I calculated the actual net volume in the a single-fold line within it that I modeled to be 2.3 ft3, not 1.846 as you state? In any event, if Pano now is okay with a much bigger box, then there would be a whole more in general to play with.
Paul
Dunno, both HR and my math agrees based on an unfolded line less driver, so there would be some minor increase and why I indicated 'more or less' [~], though didn't figure this much increase, but best to err on the large side.
Regardless, as you noted, this driver [and maybe others] offers lots more tuning flexibility than the Peerless, so at this point I'm with fakamada, we need the 'rest of the story' as ideally the bass bin needs have up to +6 dB of headroom to match up to the 'FR' driver to keep from attenuating it.
As he implied, a HE driver with digital EQ offers a myriad of tuning possibilities in a small cab if it has a decent amount of Xmax.
GM
Regardless, as you noted, this driver [and maybe others] offers lots more tuning flexibility than the Peerless, so at this point I'm with fakamada, we need the 'rest of the story' as ideally the bass bin needs have up to +6 dB of headroom to match up to the 'FR' driver to keep from attenuating it.
As he implied, a HE driver with digital EQ offers a myriad of tuning possibilities in a small cab if it has a decent amount of Xmax.
GM
I don't know what you mean by HR, but both it and your math are off quite a bit.😕 I modeled the last line to fit within a gross cabinet volume of 2.5 ft3, to satisfy Pano's original size/shape requirements, and it is 60" long and 12"W. Its starting depth is 10.5" and it ending depth is 0.5" to make the taper be 21:1. The average depth, then, is 5.5". So, 60" x 12" x 5.5"=3960 in3, or 2.2917 ft3. Another way to calculate it is to simply subtract the volume consumed by the angled divider from the gross internal volume of the 12" x 12" x 30" cabinet. The divider would be ~25" long in order to make a single-fold, tapered line. If it were arbitrarily 1" thick, its volume would be 1" x 12" x 25", or 300 in3. Subtracting that from the cabinet's gross internal volume of 4320 in3 leaves 4020 in3 or 2.326 in3. I'm also not taking into account volumes consumed by driver and braces.
Paul
Paul
HR = HornResp, a well proven program I referenced in a previous post you quoted, so am pretty comfortable with its dimensional calculations, especially since they mirror my own Excel calculators done by folks with far more advanced math skills than me.
That said, a simple folded pipe using straight divider board more closely approximates a parabolic expansion making your design's net Vb ~64.89 L/2.29 ft^3 minus driver, internal baffles and any bracing, the same as I get with my ancient Excel calculator.
Regardless, to give Mike a quick answer to this driver's viability in the desired empty box Vb, I just SWAGed [Scientific Wild A$$ Guess] how much the driver, multiple folds to make it 'complex' and some dowel bracing this would consume, so not meant to be definitive at this early stage of development.
GM
That said, a simple folded pipe using straight divider board
Regardless, to give Mike a quick answer to this driver's viability in the desired empty box Vb, I just SWAGed [Scientific Wild A$$ Guess] how much the driver, multiple folds to make it 'complex' and some dowel bracing this would consume, so not meant to be definitive at this early stage of development.
GM
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Because you're trading up to a 1/2 WL resonator with a 1/4 WL fundamental from a 1/4 WL resonator tuned by a 1/2 WL resonator.
Of course, but this has nothing to do with my narrowly defined assertion.
Yes, a PR might be a better tuning option, especially in a low tuned alignment, but it has its own performance trade-offs too and where the designer's job comes into play.
Frequency response, yes, but not electrical and/or acoustical phase response compared to some vented alignments or types of TL AFAIK.
GM
GM sorry I'm not following your explanation
what's better about a TQWT that we can specify and can be measured than either a slot loaded BR or PR?
I'm not trying to bust yer balls, I wanna learn from the masters here.
what's better about a TQWT that we can specify and can be measured than either a slot loaded BR or PR?
I'm not trying to bust yer balls, I wanna learn from the masters here.
No worries, if I thought you were, I'd just ignore you. 😉
Well, I thought I'd explained it fairly well as I understand the physics of the situation, though it does require understanding what all it implies, so short of getting educated on resonant pipe theory, then building, comparing, etc. as me and many others have done, I don't know how to explain it any more clearly; so without trying to bust yours, I'm going to fall back on a common phrase used in patents, "It will be apparent to those skilled in the art........." 😉 since for sure, I can't explain it using the electrical equivalent circuits that's been used since at least the 1920s to describe/design acoustic systems. Based on your background, I imagine you should have no trouble working it out though.
Not sure what you want specified, but comparing sims using MJK's software and at differing output impedance should give you plenty to choose from. Sure would have saved me a lot of building/testing, though probably wouldn't have learned nearly as much.
Ditto with measurements: electrical/acoustical phase, impulse response, group delay, though in the end it's ones done by ear that dominate.
GM
Ok cool
I'd be hard pressed to explain how a bass reflex works by using a helmhotz resonator to extend a speakers LF response too.
Hi Guys - thanks for all the hard work.
I had to unsubscribe and resubscribe to this thread as I was not getting notices. 😡 Hope it works now.
Anyhow. The box dimensions of 14x14x32 are pretty close to set. Maybe go deeper like 16" deep for more room as 14" is a rather shallow speaker. If a simple TQWT will work well in this size box with the SB driver, why not? The port could be down firing, yeah?
The fullrange driver is the Seas Prestige FA22RCZ . Great driver, but efficient enough that I don't see how it can be used without padding on a typical 10" woofer. That's life. Maybe it could be bi-amped later down the road. This will mostly be used with an EL-34 P-P valve amp. Like 50WPC, I think.
My guess is that the crossover from 10" woofer to 8" FR will happen circa 200-250Hz. That's about where the Sears 8" should be down 3-6dB. The rear firing tweeter is optional.
BTW, this is not my project, but a buddy of mine in London. I'll be there middle of next month to help him with crossovers and such. He's keen to start building so that they will be ready when I get there.
I had to unsubscribe and resubscribe to this thread as I was not getting notices. 😡 Hope it works now.
Anyhow. The box dimensions of 14x14x32 are pretty close to set. Maybe go deeper like 16" deep for more room as 14" is a rather shallow speaker. If a simple TQWT will work well in this size box with the SB driver, why not? The port could be down firing, yeah?
The fullrange driver is the Seas Prestige FA22RCZ . Great driver, but efficient enough that I don't see how it can be used without padding on a typical 10" woofer. That's life. Maybe it could be bi-amped later down the road. This will mostly be used with an EL-34 P-P valve amp. Like 50WPC, I think.
My guess is that the crossover from 10" woofer to 8" FR will happen circa 200-250Hz. That's about where the Sears 8" should be down 3-6dB. The rear firing tweeter is optional.
BTW, this is not my project, but a buddy of mine in London. I'll be there middle of next month to help him with crossovers and such. He's keen to start building so that they will be ready when I get there.
How is this project coming along? I have read with great interest as I have a pair of the SB 10" drivers and would really like to build a TL design as mentioned...
Kind regards,
Jai Stanley
Kind regards,
Jai Stanley
A longshot but how did this project go?
I have a pair of FA22RCZ units and want to mate them with a larger woofer in a TL to try to get to 20Hz or better in room, I propose an 18" JBL 2245H as I have a pair of them, though the QT is a bit low at 0.27 the Volt RV4564 is a possibility inspired by PMC using the 15" version the RV3863
Thanks
Simon
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