Hello everyone, I recently had the opportunity to sell my SFE-812 speaker build to a friend for a very good but fair amount of money, so I have a good budget to build another speaker and I'd like to use some higher end components.
The past week I have explored quite a few different concepts but am leaning towards the following, essentially an 18" 2-way using the AE TD18H and either something like the Radian PB850 or 950, or a coax CD like the BMS 4592ND crossed over around 500hz.
I am considering something in the 6-8ft cabinet range ported, with modeling this 18" will have no trouble producing 118db at 30hz well w/in Xmax, and should do 110db at 20hz with some EQ bump.
The idea would be to create a point source for midrange and high frequencies, it's not something I've tried yet and am curious to experiment with it.
Would be a fully active system with miniDSP and plenty of high power amplifier options.
I have been doing a lot of reading, and some complain about the high frequency extension of running one CD for mids and treble, and doesn't seem to be a ton of experience with the coax CD's.
Also looking at various horns from JBL, Selenium and others, any good horns to share that can load down to 500hz?
Any opinions or experience to share? Keep in mind my last pro driver project was linked above, so I'm looking to do something a little different but also building on what I learned from that one.
Thanks everyone!
Javad
The past week I have explored quite a few different concepts but am leaning towards the following, essentially an 18" 2-way using the AE TD18H and either something like the Radian PB850 or 950, or a coax CD like the BMS 4592ND crossed over around 500hz.
I am considering something in the 6-8ft cabinet range ported, with modeling this 18" will have no trouble producing 118db at 30hz well w/in Xmax, and should do 110db at 20hz with some EQ bump.
The idea would be to create a point source for midrange and high frequencies, it's not something I've tried yet and am curious to experiment with it.
Would be a fully active system with miniDSP and plenty of high power amplifier options.
I have been doing a lot of reading, and some complain about the high frequency extension of running one CD for mids and treble, and doesn't seem to be a ton of experience with the coax CD's.
Also looking at various horns from JBL, Selenium and others, any good horns to share that can load down to 500hz?
Any opinions or experience to share? Keep in mind my last pro driver project was linked above, so I'm looking to do something a little different but also building on what I learned from that one.
Thanks everyone!
Javad
Two Proven Bass Designs.
PPSL = Push-Pull-Slot-Loaded woofers. This cabinet generate a high impact bass wave launch with a focused air pressure energy that travels several feet before diffusing. A sealed cabinet with equalization and boost can provide the best transients and most uniform bass. A ported cabinet can provide greater efficiency. In a small room, the slot is aimed at the listener in an effort to increase the perceived dynamic impact. This directivity control is a good match to horn or dipole polar pattern. At modest SPL levels, the slot's focused energy wave is linear over a wide frequency range. The slot dimensions are smaller than the 27" 500Hz wavelength(27") to avoid resonances.
W-TM-W = Stacking one woofer under the SEOS24 and another woofer above combines the floor-effects with the ceiling-effects to help smooth out room bass modes. This topology allows ~18" center-to-center separation between the woofer and SEOS24. A 500Hz wavelength is 27" long.
PPSL = Push-Pull-Slot-Loaded woofers. This cabinet generate a high impact bass wave launch with a focused air pressure energy that travels several feet before diffusing. A sealed cabinet with equalization and boost can provide the best transients and most uniform bass. A ported cabinet can provide greater efficiency. In a small room, the slot is aimed at the listener in an effort to increase the perceived dynamic impact. This directivity control is a good match to horn or dipole polar pattern. At modest SPL levels, the slot's focused energy wave is linear over a wide frequency range. The slot dimensions are smaller than the 27" 500Hz wavelength(27") to avoid resonances.
W-TM-W = Stacking one woofer under the SEOS24 and another woofer above combines the floor-effects with the ceiling-effects to help smooth out room bass modes. This topology allows ~18" center-to-center separation between the woofer and SEOS24. A 500Hz wavelength is 27" long.
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Take a look at Pooh's thread on his HLCM - horn loaded compact monitor. In particular, post #53. He doesn't seem to have any practical constraints as far as looks and size, he is very experienced with horns, and he is using a horn for the treble and another for the midrange. However on post #53 he mentions his Faital HF144 could be the best option above 400Hz if it weren't for nasties above 8kHz which you could correct with DSP (which he is not applying).
BTW, why not a 3-way, isolating the midbass driver from also doing subwoofer duties? Or 3-way with tweter, midrange, and bass with the 18" AE?
Take a look at Pooh's thread on his HLCM - horn loaded compact monitor. In particular, post #53. He doesn't seem to have any practical constraints as far as looks and size, he is very experienced with horns, and he is using a horn for the treble and another for the midrange. However on post #53 he mentions his Faital HF144 could be the best option above 400Hz if it weren't for nasties above 8kHz which you could correct with DSP (which he is not applying).
BTW, why not a 3-way, isolating the midbass driver from also doing subwoofer duties? Or 3-way with tweter, midrange, and bass with the 18" AE?
I haven't seen any measurements to indicate that a slot loaded would hold directivity that high.
Two other ways to hold directivity lower would be a cardioid lower midrange/woofer or a 16" or narrower baffle with dipole woofers.
I've tried both routes. The cardioid measured well, but I found the sound uninvolving...
I switched over to dipole lower mids and bass after and prefer the sound.
I believe Geddes and others claim directivity isn't necessary at frequencies this low, so monopole woofer(s) would be perfectly acceptable as well.
In addition, having tried cardioid bass in a living room setting, it doesn't work. I still had the same peaks and nulls. It wasn't until I added additional subwoofers that bass response was flat to 30hz in my room.
Two other ways to hold directivity lower would be a cardioid lower midrange/woofer or a 16" or narrower baffle with dipole woofers.
I've tried both routes. The cardioid measured well, but I found the sound uninvolving...
I switched over to dipole lower mids and bass after and prefer the sound.
I believe Geddes and others claim directivity isn't necessary at frequencies this low, so monopole woofer(s) would be perfectly acceptable as well.
In addition, having tried cardioid bass in a living room setting, it doesn't work. I still had the same peaks and nulls. It wasn't until I added additional subwoofers that bass response was flat to 30hz in my room.
The SEOS 24 with a 1.4" inlet and the BMS 4594 will have a better top end than the 4592 and is usable down to 450hz.
This is the mid section only.
Very interesting, was looking at this driver too, thank you for the plot! So this was just the midrange?
What horn do you like with this driver?
Prefer the coax over a single wide range CD?
Thanks @Face!
Javad
To clarify I will be running a ported bass reflex enclosure for this project, not looking to experiment on that last of the project currently.
Last night I modeled two Kappalite 3015LF in the same 8 cubic feet and they hold up very favorably to one 18" AE so I may consider that option as well. I like the idea of flanking the horn WTW, they plan clean to 1kHz as well.
Blue is 2 Kappalite, orange is 1 TD18H, both in 8 cubic feet, both with high pass around 25hz and optimized port tuning.
Kappalite are pushing Xmax with 500w total, AE is only at 9mm and Xmax is 14mm, it can easily soak up 1000watts before hitting Xmax.
Thanks!
Javad
Last night I modeled two Kappalite 3015LF in the same 8 cubic feet and they hold up very favorably to one 18" AE so I may consider that option as well. I like the idea of flanking the horn WTW, they plan clean to 1kHz as well.
Blue is 2 Kappalite, orange is 1 TD18H, both in 8 cubic feet, both with high pass around 25hz and optimized port tuning.
Kappalite are pushing Xmax with 500w total, AE is only at 9mm and Xmax is 14mm, it can easily soak up 1000watts before hitting Xmax.
Thanks!
Javad
Thanks for the info, checking out his thread and interesting option, it is important to me that I can get flat response past 17khz which I can hear to, above that not too concerned and some of the single driver options seem to struggle past 15k
Basically what my last project was, I want to experiment with point source mid and treble, I also have looked at coax woofer/CD options as well but have never done a horn midrange so I'm leaning hard that direction.
So goals are:
- point source mid and treble
- horn midrange and treble
- vented high efficiency bass and midbass crossed over at approx 500hz. I have also considered doing a 12" midbass in a tiny sealed enclosure (down to about 80hz) coupled with a more traditional subwoofer (for example Mag 12 midbass and Lab 12 subwoofer).
Thanks,
Javad
BTW @LineSource I see you're from the Bay Area, let me know if you'd like to chat, I work in Fremont and live in San Ramon, would love to chat more, shoot me a PM or email me js@034motorsport.com
Thanks!
Javad
For WTW point source, the relationship between C to C distance, cut off frequency, slope, and listening distance, ceiling height etc. is a very interesting subject. I have been experimenting different methods, but I can't still find the final answer. I started my WTW based on Toole's linear phase AES paper, but my current DSP setting is quite different from what he suggested.
A larger concern would be the vertical directivity. In the example you quoted the woofers could be getting quite narrow below the crossover frequency, notwithstanding lobes, whereas the tweeter would be widening (or even pattern flipping) above the crossover. I'd be guessing at maybe a 3-6dB assymetric DI discrepancy.
Any of the options I've been considering play cleanly up to 1khz before they break up, I'll be xo around 500hz and can play with slopes as well, I can even keep C-t-C distances w/in one wavelength even with 15" WTW.
Regarding dispersion and directivity, these are for my audio listen room and do not require wide dispersion, and I'd like to even limit it due to keep room reflections.
I have considered that Face and certainly the same amount of cone area is not required for mid frequencies than mid bass and bass.
Would allow me to mount the horn above the enclosure too in an artful way. And in that case I'd order 4ohm drivers and run them off delegate amps, or incorporate a passive low pass in the 2.5 woofer.
Strongly leaning towards dual TD15H drivers per can currently.
Thanks!
Javad
Something like this:
https://imgur.com/8hnuKlk
https://imgur.com/QgZMdd7
Solid mahogany structures. No poly or wax on them, yet. A nasty hernia and knee damage/surgery put speaker building and finishing on hold for a bit.
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