How about this...?

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The Infinity is close, though doubt its Fs and Qes are as low as listed, so wouldn't be my first choice unless there's no other options.

I've got two of those drivers in storage. The specs are believable.

Also semi-inductance parameters (set to 4 ohm operation)

Re': 4.51 ohms
Leb: 1.45 mH
Le: 6.65 mH
Ke: 0.34 sH
Rss: 150.75 ohms

They are no longer manufactured however. I was planning to use them in passively-assisted sealed enclosures which will have them getting down to 30 Hz in small sealed boxes.
 
Well, it does it as a 'one note' peak and has an increasingly higher peak rating above ~50 Hz, but in the strictest sense it's only a ~45 W wide band alignment with some limited dynamic headroom, so find this sort rating very misleading without showing where its Xmax is exceeded and by how much.

It's an home theater sub, not pro audio. If there's too much mid bass, then lower the low pass filter.

Check out the Devastator index on avsforum.com. All the frequency responses rise up WITH PRO AUDIO DRIVERS and JBL car audio sub.

I actually built my car's BP4 with a similar curve and the sound is great with both boom bap (40hz & up) and trap 40hz & down) music.

People complain about BP4 and BP6's being 1 note wonders because when you build a perfectly flat 2 Pi enclosure, the lower frequencies will be exaggerated in a 0.5 Pi environment. Build a 2 Pi enclosure with a rising response to the crossover frequency, then you have a flat response in a 0.5 Pi environment.
 
Example: I built my home theater subwoofer with a flat 2 Pi response while expecting it to fire into a corner (0.5 Pi). I ended up turning the enclosure 180* and it's been in that position ever since. The mid bass picked up considerably from that slight change.

1st pic, 2012. Sub firing into corner. 2nd pic, 2016. Sub turned 180*. 3rd pic, 2019. Sub further away from the corner
 

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Yes, big SPL numbers down low = big bucks and/or size. As for elegant, they don't need to be in sight.
I know, but what I really need is LOW, am not a hard-core SPL, a fair number at 8ft would be pleasing. :)

Well, he used Xvar instead of Xmax and due to him inputting a voltage for power it doesn't show that it runs out of Xvar at ~ 80 W if you the use HR's Wizard or just input it in the Acoustical Power window......... Not many 'free lunches' in audio design, so wasting $$ on a high power amp.
I see, it was a mistake then...
 
I've got two of those drivers in storage. The specs are believable.

Also semi-inductance parameters (set to 4 ohm operation)

Re': 4.51 ohms
Leb: 1.45 mH
Le: 6.65 mH
Ke: 0.34 sH
Rss: 150.75 ohms

They are no longer manufactured however. I was planning to use them in passively-assisted sealed enclosures which will have them getting down to 30 Hz in small sealed boxes.

Cool! Thanks! So many of the low Fs spec'd drivers I've helped folks with have higher Fs, Qt, lower Vas to the point where they're inherently under damped in recommended cabs.

So, can I be alright with INFINITY now? How would the T-TQWT respond to one of those ~ 20hz fs drivers I mentioned?
 
Well, it does it as a 'one note' peak and has an increasingly higher peak rating above ~50 Hz, but in the strictest sense it's only a ~45 W wide band alignment with some limited dynamic headroom, so find this sort rating very misleading without showing where its Xmax is exceeded and by how much.

It's an home theater sub, not pro audio. If there's too much mid bass, then lower the low pass filter.

Check out the Devastator index on avsforum.com. All the frequency responses rise up WITH PRO AUDIO DRIVERS and JBL car audio sub.

I actually built my car's BP4 with a similar curve and the sound is great with both boom bap (40hz & up) and trap 40hz & down) music.

People complain about BP4 and BP6's being 1 note wonders because when you build a perfectly flat 2 Pi enclosure, the lower frequencies will be exaggerated in a 0.5 Pi environment. Build a 2 Pi enclosure with a rising response to the crossover frequency, then you have a flat response in a 0.5 Pi environment.
Actually my favour is low-passing @ 60hz, and to let my stereo do the rest.

The real complication is I'm (awefully?) a fan of both classic & hiphop, so I need deep-digging lows as well as crystal-clear highs... :D

I remember how my 6BP (of course known as one-note wonders) led to a "resonator" debate here in the beginning, now it's about the T-TQWT's "bandwidth", and what makes the debate more and more interesting is that I don't know any of these. :rofl:
 
Example: I built my home theater subwoofer with a flat 2 Pi response while expecting it to fire into a corner (0.5 Pi). I ended up turning the enclosure 180* and it's been in that position ever since. The mid bass picked up considerably from that slight change.

1st pic, 2012. Sub firing into corner. 2nd pic, 2016. Sub turned 180*. 3rd pic, 2019. Sub further away from the corner
Ah, the double-fold... What if I limit the T-TQWT to a narrow bandwidth (by filtering) like, say 20-60hz?
 
i geek out on using a few layouts which tend to be ‘best’ for certain freqs and particular to the bas regions as 45Hz plus and 45 below..

Using a 2x dayton audio rss/2x skar audio ddx paraflex for 40+ ( options are 26-40hz Fb) and using a dayton audio 15 x2 ultimax in an offset(or end fired, not quite sure but looking at phase in both boxes to be agreeable in room ) ML tapped qw pipe for the bottom(14-16hz Fb).

theres dayton audio RSS100 /peerless silk 26 mm MtMww with tangband W5-1138f for the W in offset entry Qw pipes ...

But all this junk runs through dayton 408s to the 1000 watt sub amps racked and multi 6 channel amp which goes to individual amp channels/drivers so everything has its own dsp controls.

Then i repeat something similar as car audio...with.hivi 4” drivers and peerless 6.5s and (of course) an isobaric MLTL using rockford fosgate p3 12”s sometimes a singke skar 12 ddx paraflex if i can steal the dsp channel to fix the crazy up top that screams at a window of agony around thre area both pipes imaginery junction(phase fawkery) it is insane and thanks to david i can fix it easily in Hr..


lately ive been checking sub harmoinc stuff from old audio control epicenters with a 15hz plug??? Like amazon or even second hard. a friend on Qw FB group makes didgeridoos outta pvc and now speakers qw pipes in the same way, and hes into the subharminc blood curtailing regions (7.2 hz feels Nice!???)
 
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i geek out on using a few layouts which tend to be ‘best’ for certain freqs and particular to the bas regions as 45Hz plus and 45 below..

Using a 2x dayton audio rss/2x skar audio ddx paraflex for 40+ ( options are 26-40hz Fb) and using a dayton audio 15 x2 ultimax in an offset(or end fired, not quite sure but looking at phase in both boxes to be agreeable in room ) ML tapped qw pipe for the bottom(14-16hz Fb).

theres dayton audio RSS100 /peerless silk 26 mm MtMww with tangband W5-1138f for the W in offset entry Qw pipes ...

But all this junk runs through dayton 408s to the 1000 watt sub amps racked and multi 6 channel amp which goes to individual amp channels/drivers so everything has its own dsp controls.

Then i repeat something similar as car audio...with.hivi 4” drivers and peerless 6.5s and (of course) an isobaric MLTL using rockford fosgate p3 12”s sometimes a singke skar 12 ddx paraflex if i can steal the dsp channel to fix the crazy up top that screams at a window of agony around thre area both pipes imaginery junction(phase fawkery) it is insane and thanks to david i can fix it easily in Hr..


lately ive been checking sub harmoinc stuff from old audio control epicenters with a 15hz plug??? Like amazon or even second hard. a friend on Qw FB group makes didgeridoos outta pvc and now speakers qw pipes in the same way, and hes into the subharminc blood curtailing regions (7.2 hz feels Nice!???)
I know I can do better with Dayton/Peerless/Rockford/Skar since they're pretty versatile, but unavailable in here.

Yes, a DIDGERIDOO seems to dig deep (can I have the link to that FB group or some photos?), but again we don't get that chance, many people in our country don't care about the ~ 20hz region, they're pleased with the booming 40hz +.

Which type of enclosure would you assume will do the 20hz (or lower) in your experience, my friend can make anything?

BTW, how about this (found online recently), looks like an infinite/isobaric/qw/th whatever but never seen before... :D
 

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As shown it's a dual driver ML-TQWT [aka what I call an ML-horn since it expands]. This is fundamentally one of the so called BIB horns except with a restricted terminus [vent] I played with in the mid '60s-70s with the guy that turned me on to TLs.
 
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Actually my favour is low-passing @ 60hz, and to let my stereo do the rest.

The real complication is I'm (awefully?) a fan of both classic & hiphop, so I need deep-digging lows as well as crystal-clear highs... :D

I remember how my 6BP (of course known as one-note wonders) led to a "resonator" debate here in the beginning, now it's about the T-TQWT's "bandwidth", and what makes the debate more and more interesting is that I don't know any of these. :rofl:

Sure you can! I just use the typical 80hz crossover frequency.

Actually, 60hz and below are more ideal for any type of TH. The problem is the enclosure size gets HUGE.
 
I know I can do better with Dayton/Peerless/Rockford/Skar since they're pretty versatile, but unavailable in here.

Yes, a DIDGERIDOO seems to dig deep (can I have the link to that FB group or some photos?), but again we don't get that chance, many people in our country don't care about the ~ 20hz region, they're pleased with the booming 40hz +.

Which type of enclosure would you assume will do the 20hz (or lower) in your experience, my friend can make anything?

BTW, how about this (found online recently), looks like an infinite/isobaric/qw/th whatever but never seen before... :D

I prefer the sound (low distortion) and speaker protection of buried driver enclosures...FLH, TH, BP4, & BP6. I'm not 1 of those people who needs to see the driver or see it move.
 
As shown it's a dual driver ML-TQWT [aka what I call an ML-horn since it expands]. This is fundamentally one of the so called BIB horns except with a restricted terminus [vent] I played with in the mid '60s-70s with the guy that turned me on to TLs.
True, it looks a lot like a mass-loaded kinda horn, but I'm curious of that infinite-baffle kinda driver placement, what could be the real purpose of leaving the back energy in the free air? I don't remember from where I picked that pic, so just having a non-informative drawing how to build this? And who knows what at what frequency it'd play (though I know it's something about the ~ 20hz cos I found it when Googling for "infrasonic", barely remember)? :confused:
 
i like the BIB concept a LOT too!

theres one recenty with a couple hivi b4ns in it that had an agreesive expanding shape that then was terminated into a mass loaded port which was offset slightly from the actual 'other closed end' and the results were crazy.

two odd (harmonc)points of interest got snatched up it seemed and the bandwidth was esentially flaiwless for a fullrange apllication as an MtM.. like a QW hypedup Overnight Senseations pair?


that FB group is "quarterwave Theory" benjermin dodson.

its active and growing quick finally.. if any of you guys are bored and wanna add another place to goof off and spitball qw and similar ideas, youre already accepted, done deal:D
 
I'm curious of that infinite-baffle kinda driver placement, what could be the real purpose of leaving the back energy in the free air?

Well, the room is ~ an 'infinite' baffle to any speaker that has one side open to it. ;)

IOW, it's one big parabolic horn split in half with a driver mounted to each half, then sums in the large main chamber with vent.

Why leave one side of any speaker driver in open air, he asks rhetorically? ;)

In short, it's a dual driver, end loaded, vented, BLH and the rear of the driver is exposed due to there not being enough internal depth to mount it normally.
 
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