Right, I over abbreviated in my haste.......
13560"_sec [SoS at my locale]/pi = the diameter of a ~796 Hz WL and an octave below it [~398 Hz] is a good place to have a 2nd order XO point since 1/2 the music power is below 500 Hz where a 15" woofer can be close coupled to a fairly large driver.
The pioneers concluded 500 Hz XOs for their two way horn or woofer+horn systems was the best overall compromise, but the concept works fine with wide range point source drivers too while maintaining high speech intelligibility.
GM
13560"_sec [SoS at my locale]/pi = the diameter of a ~796 Hz WL and an octave below it [~398 Hz] is a good place to have a 2nd order XO point since 1/2 the music power is below 500 Hz where a 15" woofer can be close coupled to a fairly large driver.
The pioneers concluded 500 Hz XOs for their two way horn or woofer+horn systems was the best overall compromise, but the concept works fine with wide range point source drivers too while maintaining high speech intelligibility.
GM
GM - okay, that I follow more, thanks! 🙂
13560 in/sec is speed of sound.. that should have been obvious... oops!
I seem to recall a similar rule of thumb for what size drivers effectively couple to what frequencies...
Doing a FAST setup, I was trying to cross as low as possible to try to keep the vast majority of the vocal range playing thru the FR driver, and just sending the heavy stuff to the big woofer to minimize the excursion of the FR driver. Would there be a benefit to crossing it higher up around 500 as the pioneers did? They didn't have Alpair 10.3s though... but I guess they did have nice alnico stuff then.
Dave - I guess that is pretty big, at least height wise 🙂
But not sure big enough sound wise for my tastes - I'd have to hear it first!
Looks nice, all bass reflex/aperiodic?
Maybe counter bore some holes top/bottom of enclosures and pin them together with large but short dowels...
13560 in/sec is speed of sound.. that should have been obvious... oops!
I seem to recall a similar rule of thumb for what size drivers effectively couple to what frequencies...
Doing a FAST setup, I was trying to cross as low as possible to try to keep the vast majority of the vocal range playing thru the FR driver, and just sending the heavy stuff to the big woofer to minimize the excursion of the FR driver. Would there be a benefit to crossing it higher up around 500 as the pioneers did? They didn't have Alpair 10.3s though... but I guess they did have nice alnico stuff then.
Dave - I guess that is pretty big, at least height wise 🙂
But not sure big enough sound wise for my tastes - I'd have to hear it first!
Looks nice, all bass reflex/aperiodic?
Maybe counter bore some holes top/bottom of enclosures and pin them together with large but short dowels...
Well, what works by my definition is that a well damped, acoustically large cab is key, so you're getting the bulk of it with the BIB. Tall enough offset driver MLTLs or ML-horns [aka ML-Voigts] to audibly shorten the vent [or require a larger one] and if not tall enough [< 42" IME], then raise the vent as required to get a bit more damping.
A nominally tonally flat response in the 500-3000 Hz BW, otherwise [+/-3 dB] from at least 60-13 kHz [ancient Altec studio monitor spec]. Below this just adds 'fullness' and above, top end 'air'.
Note that for me, my ~life-long tinnitus dictates dips centered at 2, 4, 8 kHz, where many folks like a boost as it adds 'presence', 'depth' to the soundstage, so recommend similar for any others that have constant background 'ringing'.
GM
007,
How about combinig a few approaches and coming up with something useful? I was thinking about this:
DTQWT-mkII
But, let's say you build it partially, just a woofer section of Dtqwt. Maybr you could use some cheaper 12" eoofer, maybe even 12 lta? Then you add an Alpair 10.3 Em-ken on top of it. I was just thinking, why not...you would get nice tone from Alpairs, and a 'kick' from the woofer...
How about combinig a few approaches and coming up with something useful? I was thinking about this:
DTQWT-mkII
But, let's say you build it partially, just a woofer section of Dtqwt. Maybr you could use some cheaper 12" eoofer, maybe even 12 lta? Then you add an Alpair 10.3 Em-ken on top of it. I was just thinking, why not...you would get nice tone from Alpairs, and a 'kick' from the woofer...
Re: toe tappin
Thanks GM. Yes the BIBs definitely have it. I am planning on building the Moose designed BVR, Maria Chang, for the eminence beta 12lta. Plans in post #90 of this thread. I am not clear on the timeline of the Chang BVRs from 2007, but I think you helped with the design in some form. Not sure if it meets the criteria for toe tappin. But it does appear to have elevated frequencies in the punch range so that should be good for Rock n Roll. I hope/ think. I have got the wood so hopefully a review is not too far off.
Thanks again GM
Thanks GM. Yes the BIBs definitely have it. I am planning on building the Moose designed BVR, Maria Chang, for the eminence beta 12lta. Plans in post #90 of this thread. I am not clear on the timeline of the Chang BVRs from 2007, but I think you helped with the design in some form. Not sure if it meets the criteria for toe tappin. But it does appear to have elevated frequencies in the punch range so that should be good for Rock n Roll. I hope/ think. I have got the wood so hopefully a review is not too far off.
Thanks again GM
You're welcome! The way I remember it, at most, I only gave Scott some BVR horn rule-of-thumb guidelines/theory and with MJK's most excellent software, the rest as they say, is history 😉.
Then again, from just looking at the sim in the pdf, maybe not as my info makes more midbass to acoustically offset baffle step.
GM
Then again, from just looking at the sim in the pdf, maybe not as my info makes more midbass to acoustically offset baffle step.
GM
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GM
Can that be resolved with a 18-24" diameter super baffle on the front or a BSC added?
Thanks
Can that be resolved with a 18-24" diameter super baffle on the front or a BSC added?
Thanks
Judge for yourself. Drawing does not show the base… with that it will be > 1.8m tall.
dave
In keeping with your 1/4 wavelength mantra and that driver spacing you must be crossing over pretty low, no?
Vix - That's exactly what I'd like to do - combine any useful designs/techniques I can into one speaker... or at least in theory. In practice, the outcome may not be better but may be worse instead, such as it is with experimenting. And the favorite drivers of the day are the 10.3 and a large woofer 15-18" of indeterminate specs. I haven't the time nor expertise for simulating something like this - at least not yet. That's why I was hoping to follow in someone (who knows more than I do) else's footsteps, and hopefully recreate their success story.
Rather than try to reinvent the wheel... (though this is what we are prone to do!)
And to avoid the risk in building something that doesn't sound any better than what I have (or worse, yikes!)...
Re: DTQWT design, I quite like the concept... Just don't know how it sounds outside of the designer's description (though with two 12's in the back, I'd guess it would meet my requirements as well!) And the price tag with those components is well outside my budget. I'm still not sure how I'd like the bass coming out of the bass horn section, vs. something like a single sealed 18". I've been staring at sims and charts and graphs for hours & hours now, but it's still hard to mentally compare the sound of a smaller woofer that is better coupled to the air vs. a larger woofer that is less coupled and more damped. Also, a simple sealed 18" is bound to move some air and provide some punch - I can't really mess it up. A complex horn on the other hand, that isn't a tried/true design, with the drivers I end up using... well that could be a recipe for disaster obviously!
My mental picture of what to build currently looks something like a 15" or 18" in a sealed/slot vented/horn enclosure on the floor for 30-150(?) hz. And with something like a 10.3 Alpair on top in a P10 Onken design, or sealed, or just simple BR, or BIB (except due to its height it probably won't stack well), or other MLTL/TWQT design (still having a hard time seeing how the different enclosures affect the mids/highs) on the top for 150-16,000 hz.
I'm also on the proverbial fence regarding the full range driver to use in this FAST setup... despite glowing reviews/reports on many of these full rangers, I'm still drawn to the larger drivers like the 12lta and Fane (and others to be sure, some 8"s and 10's as well). I'm concerned that despite their nice freq plots, the smaller FR drivers might sound tinny and small... Is this just not the case? Keep in mind I'm used to the sound of bigger 3-way floor standing speakers... With an 11" effective diameter woofer (ported) ***, 3.25" effective dia mid, and a plastic dome tweeter. And I want BIGGER sound than this.
***The woofers in my 3-ways play up to 1600 hz, so that's a lot of air moving from 45-1600 hz; after that the mid takes over, and with only a 3.25 effective dia, most of the FR offerings should move as much or more air...
I just keep staring at the little 2.1 setup on my pc, little full range drivers and a sub on the floor (which is a FAST system by definition) - it's more than adequate to listen to background music on, even sounds good cranked up quite a bit (sounds much better than the lame HT in a box setup I have that was long ago banished to garage music duty) - but it just can't compete with the fisher 3-ways in the living room when you really want to jam or watch a movie.
GM - If half the music power is below 500 hz and half above... Crossing at 500, 80/2w = 40w per driver? This doesn't seem to work in my head... The woofer would still be getting 80w but only at low frequencies, and the tweeter would still be getting 80w worth of the high stuff, no? --I guess that's at 80w rms, where there are peaks and valleys, 0w-160w, and I'm not sure if the higher peaks are dominated by LF/HF/both? (I suspect low).
Crossing at 150hz would mean even more music power going to the FR...
.
I'm worried about a smaller FR like the 10.3 or 12P getting cooked from seeing 150hz on up, with the volume knob cranked to 11 (since they are rated at only 30w).
Also, I don't think I have tinnitus, but I do get odd things happening at certain frequencies; the sound of applause, the clapping part at a big event will do something weird and all I hear is a sort of slightly painful static... maybe a resonance inside my ear.. As a result, I tend to tone down the highs a bit as well.
Thank you all for your input!
You're welcome!
BSC, of course, at the expense of efficiency. IME it takes at least a 30" wide baffle, but in today's often smaller rooms, a smaller baffle could suffice I guess.
GM
Time will tell. Given the drivers XO could be anywhere from 100 Ha or so up into the kiloHz. XO will likely be related to bafflestep frequency which may push the ¼ wl a bit. Centre-to-centre is ~570 mm -> 150 Hz ¼ w/l. The goal of this system is to be big and brash, capable of rocking. For greater fidelity we’d choose A7x/A6x/A5 as the midtweeter which would tighten up the ¼ w/l distance. We have already done an MTM were things are squeezed as close as possible and that gives a ¼ w/l of 255 which is really close to a suitable BS frequency. WE XO them at 240-250 Hz.
dave
No point in an enclosure that tries to get as musch bass as possible out of th emidtweeter if you are using it 150 Hz up. A simple sealed or aperiodic TL would be better.
No. You should check out how many times when people 1st here a set of FH3s people say “i can’t believe that it is only a 4” driver"
I believe modern studies put that frequency at about 300 Hz, but it does depend on musical genre.
dave
Don't even need a BVR/BLH for the late, lamented EL70, a stereo pair in little MLTLs had my buddies' apartment neighbors wanting to hear his new big woofer party speakers playing DSOTM 😀. A real pity we had no camera........
GM
The EL70 was able to do amazing bass… only surpassed by the Alpair 10.2 (just by a small bit) and the A12pw which is speciafically designed for bass and only extended range.
dave
dave
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