I'm very interested in hearing people's advice as I'm in the process of building a set of open baffles (first time speaker builder). I already have a pair of full range Lii Audio Crystal 10's mounted on 15 x 19 inch solid maple baffles and burning in (close to 100 hours).
I'm waiting on a pair of Acoustic Elegance Dipole15 - Dual-8ohm drivers to show up in a week or so. I want to mount them on 24 (W) x 36 (H) inch solid maple baffles. Should they be centered as much as possible on 3 sides or off centered and how far from the bottom? I understand there aren't many options due to the fact that the baffle will only be 24 inches wide.
I have a Primare A32 power amp. Here's a rear pic.
Since I have 2 sets of speaker inputs on the power amp, I was thinking of running the Crystal 10's to the top speaker inputs without crossovers (that's how they're being played now) and the AE woofers to the bottom speaker inputs. I know I'll need an inductor on the woofers to keep high frequencies from going to them. I need to know if that hook up will work without harming the amp or speakers. If that hook up will be okay I'll have more questions. Thanks for any advice.
I'm waiting on a pair of Acoustic Elegance Dipole15 - Dual-8ohm drivers to show up in a week or so. I want to mount them on 24 (W) x 36 (H) inch solid maple baffles. Should they be centered as much as possible on 3 sides or off centered and how far from the bottom? I understand there aren't many options due to the fact that the baffle will only be 24 inches wide.
I have a Primare A32 power amp. Here's a rear pic.
Since I have 2 sets of speaker inputs on the power amp, I was thinking of running the Crystal 10's to the top speaker inputs without crossovers (that's how they're being played now) and the AE woofers to the bottom speaker inputs. I know I'll need an inductor on the woofers to keep high frequencies from going to them. I need to know if that hook up will work without harming the amp or speakers. If that hook up will be okay I'll have more questions. Thanks for any advice.
Please understand I don't have the 15's yet. Hopefully they'll be here by this time next week. The specs say the10's can go all the way down to 31.5 Hz but when played alone they are pretty soft up until 2000 Hz.
The specs say the15's can go up to 2kHz. I was thinking of placing an inductor on the 15's set for 900 or 1200 Hz and doing nothing to the 10's. I presently have the 10's playing along with my sub-woofers and the subs beef up the 10's mid-range and pretty much carry all the bass. When I turn the subs off the 10's sound pretty lean, but when I play the 10's and subs together they sound quite good.
Am I wrong in thinking with open baffle unless the baffle is quite large I'll be losing deeper bass in all drivers?
The specs say the15's can go up to 2kHz. I was thinking of placing an inductor on the 15's set for 900 or 1200 Hz and doing nothing to the 10's. I presently have the 10's playing along with my sub-woofers and the subs beef up the 10's mid-range and pretty much carry all the bass. When I turn the subs off the 10's sound pretty lean, but when I play the 10's and subs together they sound quite good.
Am I wrong in thinking with open baffle unless the baffle is quite large I'll be losing deeper bass in all drivers?
>Am I wrong in thinking with open baffle unless the baffle is quite large I'll be losing deeper bass in all drivers?
Nope. The bass is going to have a very different character as well, from what your subs do. I happen to like the way it sounds, others may miss the "gut punch" and propagating into all other living spaces that a sealed or reflex box provides.
You didnt mention how you're going to provide the EQ for the 15", part of which needs to rise in amplitude as frequency falls - besides eventually falling as frequency rises to match the "top" drivers. This compensates for the finite, practical geometry of the 24X36" board those drivers will be mounted on. I dont even know of a passive way to do that; I'm using DSP (built into my amp) to dial up that one.
You can run the top driver full range, but eventually at some SPL the cone motion due to the low frequencies being present will start to distort the rest of the sound. I have the Lii 15" and cross them at ~100Hz, mostly to get rid of that excess cone motion that they would have, running full range. I have 18"s on the bottom and prefer to keep them doing "sub" 100 Hz duty.
Centered on the board in the 24" dimension, toward the floor in the 36" - or maybe it's the other way around? I'd go more toward the floor in any case. You can also build "tunnels" on the back side to assist the baffle board in keeping the cone emission from the back of the speaker from wrapping right around and cancelling the front side emission. This would also demand less compensating EQ, making your amp a bit happier. I've yet to fabricate tunnels for my 18"s.
FWIW and good luck with your new OBs!
Nope. The bass is going to have a very different character as well, from what your subs do. I happen to like the way it sounds, others may miss the "gut punch" and propagating into all other living spaces that a sealed or reflex box provides.
You didnt mention how you're going to provide the EQ for the 15", part of which needs to rise in amplitude as frequency falls - besides eventually falling as frequency rises to match the "top" drivers. This compensates for the finite, practical geometry of the 24X36" board those drivers will be mounted on. I dont even know of a passive way to do that; I'm using DSP (built into my amp) to dial up that one.
You can run the top driver full range, but eventually at some SPL the cone motion due to the low frequencies being present will start to distort the rest of the sound. I have the Lii 15" and cross them at ~100Hz, mostly to get rid of that excess cone motion that they would have, running full range. I have 18"s on the bottom and prefer to keep them doing "sub" 100 Hz duty.
Centered on the board in the 24" dimension, toward the floor in the 36" - or maybe it's the other way around? I'd go more toward the floor in any case. You can also build "tunnels" on the back side to assist the baffle board in keeping the cone emission from the back of the speaker from wrapping right around and cancelling the front side emission. This would also demand less compensating EQ, making your amp a bit happier. I've yet to fabricate tunnels for my 18"s.
FWIW and good luck with your new OBs!
At least with the Acoustic Elegance Dipole15 you'll have the two voice coil windings paralleled, so you'll have 4 Ω, which means more powered delivered to the bass, and a smaller inductor( compared to the value needed for 8Ω) to cross it to the Lil Audio.
The two sets of binding posts are useful for doing all the necessary (bi) wiring, but not necessary, I mean, if there was only one set of binding posts the project would be the same
The two sets of binding posts are useful for doing all the necessary (bi) wiring, but not necessary, I mean, if there was only one set of binding posts the project would be the same
Hi,
even with the Dipole 15 wired in 4Ohm, you´re facing a massive sensitivity mismatch if you´re not going active or applying some sort of filter to the 10". A single inductor on the 15" will, if sized right, correct the baffle loss, but will not help a lot as a filter for the middle frequencies, so both drivers will play along together at quite some frequency range, at different levels.
Sorry, but this is not gonna work well...
All the best
Mattes
even with the Dipole 15 wired in 4Ohm, you´re facing a massive sensitivity mismatch if you´re not going active or applying some sort of filter to the 10". A single inductor on the 15" will, if sized right, correct the baffle loss, but will not help a lot as a filter for the middle frequencies, so both drivers will play along together at quite some frequency range, at different levels.
Sorry, but this is not gonna work well...
All the best
Mattes
I've used very limited EQing before with J River once or twice but didn't like the changes it made in the sound quality (probably because I didn't know what I was doing). Now I use Signalyst HQ Player and I think it would be a lot more complicated. Since I don't know what I'm doing I'd hate the thought of experimenting and messing up the good sound I have now.
I plan to mount the woofers with the baffle oriented 24 inches wide and 36 inches high. How close to the floor should I put the woofers, 3 or 4 inches?
And could you please explain what a "tunnel" is or upload a picture of one? I am thinking about putting panels on both sides of the woofers maybe 11 - 12 inches deep & 21 - 24 inches tall. One way to support the baffle boards and keep them upright. Is that the same thing as a "tunnel?" I also thought about regular metal braces.
I plan to mount the woofers with the baffle oriented 24 inches wide and 36 inches high. How close to the floor should I put the woofers, 3 or 4 inches?
And could you please explain what a "tunnel" is or upload a picture of one? I am thinking about putting panels on both sides of the woofers maybe 11 - 12 inches deep & 21 - 24 inches tall. One way to support the baffle boards and keep them upright. Is that the same thing as a "tunnel?" I also thought about regular metal braces.
Tunnel is properly called U frame, and there is also an H frame ( double tunnel!)
About EQ, it's needed for the bass that is lost due to acoustical short-circuit.
You can raise the bass (++dB)> Active EQ
You can lower the treble ( shelving low pass filter)> this is how passive EQ at power level is performed by an inductor ( 1st order lowpass) or inductor+ capacitor ( 2nd order lowpass) or LCL ( 3rd order LP) or LCLC ( 4th order LP ) etc.
BUT
with the signal processed & EQed and sent to the amplifier, the same signal will be amplified and sent to the speakers. Now, if you lift +10 dB the bass, the same signal ( large amplitude) goes to the other driver, and that's bad. One solution is to have two amplifiers, and a line-level crossover that sends the right signal to each driver. This is called active ( multi-amping).
AH ah! You'd rather have two sets of ( stereo) binding posts and two (stereo) amplifiers and a line-level crossover with its own tailored response to your needs, instead of a stereo amp with double binding posts!
But there's the old school of doing it, which is the ol' passive crossover, and you only lose dB's...
So if you tilt the bass, the other speaker will suffer most because it is not designed to reproduce low bass at high power...because you have lots of power from the Primare amp.
...I hope Leonidas chimes in
About EQ, it's needed for the bass that is lost due to acoustical short-circuit.
You can raise the bass (++dB)> Active EQ
You can lower the treble ( shelving low pass filter)> this is how passive EQ at power level is performed by an inductor ( 1st order lowpass) or inductor+ capacitor ( 2nd order lowpass) or LCL ( 3rd order LP) or LCLC ( 4th order LP ) etc.
BUT
with the signal processed & EQed and sent to the amplifier, the same signal will be amplified
and sent to the speakers. Now, if you lift +10 dB the bass, the same signal ( large amplitude) goes to the other driver, and that's bad. One solution is to have two amplifiers, and a line-level crossover that sends the right signal to each driver. This is called active ( multi-amping).AH ah! You'd rather have two sets of ( stereo) binding posts and two (stereo) amplifiers and a line-level crossover with its own tailored response to your needs, instead of a stereo amp with double binding posts!
But there's the old school of doing it, which is the ol' passive crossover, and you only lose dB's...
So if you tilt the bass, the other speaker will suffer most because it is not designed to reproduce low bass at high power...because you have lots of power from the Primare amp.
...I hope Leonidas chimes in
That's not likely to sound good. One thing to be very aware of is that if you choose an inductor value for 900-1500 Hz (1-1.4 mH for 8 ohms) that isn't going to work well for open baffle woofers. It doesn't even seem like a good point for box woofers.
This is what you must learn if you want to make a good open baffle speakers:
There will be significant bass loss on open baffle. How much at at what frequencies depends on the baffle and the Qts of the woofers. Low Qts woofers will have less bass on OB, high Qts (near 1) will have more bass.
To correct for this bass loss - which can be 10db or even more, you have to attenuate the top end response. This can be done fairly easily by using a large inductor. You could end up with 12-22 mH depending on woofers and baffle. You can't use a crossover designed for a box woofer on OB and expect the same results.
A woofer on OB will sound unbalanced without help. It will have too much top end and not enough bass. The first thing you must do is deal with that.
For some ideas, you might want to look at this thread.
Fast, fun, Inexpensive OB project
FWIW, about 6 years ago I made a quick and easy set of open baffle speakers using two GRS 15" woofers per side with a vintage 8" fullrange above. IIRC the woofer inductors was about 15mH. There is a cap and resistor on the 8", but I don't remember the values.
I gave them to a friend who is an audio engineer and he put them in his living room. Last night he messaged me to say that the speakers were still working and sounding great, he loves them. I get pics and an update every year. It's the gift that keeps on giving.
I gave them to a friend who is an audio engineer and he put them in his living room. Last night he messaged me to say that the speakers were still working and sounding great, he loves them. I get pics and an update every year.
It's the gift that keeps on giving.As you are only experimenting at this time I would suggest a crossover point around 600c/s might work better for you.
This would give the 10" driver some acoustic latitude to deal with the low frequencies you'll be driving it with. The crossover attenuation you are implementing is only at 6 db/oct., not nearly enough for good overall sound.
The baffle shape and size has an enormous effect on the frequency response of a driver and it's dispersion.
One option of course is to minimize the baffle size for the midrange driver, better still, mount the driver at the top of the baffle half on ... half off. This will help improve the midrange frequency response and its openness.
C.M
This would give the 10" driver some acoustic latitude to deal with the low frequencies you'll be driving it with. The crossover attenuation you are implementing is only at 6 db/oct., not nearly enough for good overall sound.
The baffle shape and size has an enormous effect on the frequency response of a driver and it's dispersion.
One option of course is to minimize the baffle size for the midrange driver, better still, mount the driver at the top of the baffle half on ... half off. This will help improve the midrange frequency response and its openness.
C.M
Yes, an acoustic crossover circa 500-700Hz usually works well. With the large fullrange, you might even go an octave lower. As Tweet says, you'll be using a 1st order high pass, so the fullrange will continue to contribute significantly below the crossover point.
Setting the woofer low pass near 100Hz or 12mH is a good start which will pull the top end of the woofer down enough to match the fullrange. As mentioned, the driver and baffle will make a big difference to the bass response.
Setting the woofer low pass near 100Hz or 12mH is a good start which will pull the top end of the woofer down enough to match the fullrange. As mentioned, the driver and baffle will make a big difference to the bass response.
I posted a pic of the full range drivers on their baffles (15 x 19 inches) at the beginning of this query. My plan is to connect those baffles at the top of the 24 x 36 inch baffle for the woofers. I plan to mount the woofers so there's 4 inches from the bottom of the woofer to the floor, 3 inches on each side of the woofers, leaving 14 inches of solid wood above the woofers.
So you're saying:
1. set the full range crossover for about 600 Hz and attenuate frequencies below that and
2. set the woofer crossover around 100 Hz and attenuate high freqencies above that?
Pano, I'll be looking forward to the results of your simulations, thanks.
So you're saying:
1. set the full range crossover for about 600 Hz and attenuate frequencies below that and
2. set the woofer crossover around 100 Hz and attenuate high freqencies above that?
Pano, I'll be looking forward to the results of your simulations, thanks.
Here is what Basta! says for your AE Dipole15-8D woofers on a 24x36" baffle. XLbaffle agrees.
Black is the response on baffle with no filter, magenta is with a 9mH inductor in series. Also shown is impedance on the dashed lines. This shows that is you want the flattest bass response in a large room, you'll have to give up about 10dB in efficiency. That's typical. However, room gain will count for a lot, and you might end up with near 4mH for flattest low end. That room gain will help a lot. But it depends of course on your room and your placement of the baffles.
The second graph shows what the response might look like with room gain and the 4mH inductor.
Next you'll need to figure out what high pass is needed to put you 3dB down circa 450 hz. Nominally 44uF @ 8 ohms, but probably much less because of natural low end roll-off. That give you a first order crossover. If you feel that teh woofer is contributing to much up top, you can experiment with a large cap (~22uF) across the woofer. That will roll off the top end faster than just the inductor alone. I suggest buying a range of cap values from P.E. or Madisound to experiment with. Buy the non-polar electrolytic caps to experiment with, then figure out if you want to invest in $$$ caps when you settle on a value. Getting the value right is the most important thing. A nice film cap isn't going to sound good if it's the wrong value.
P.S. Just put the woofer in the center near the top. Moving it around on the baffle didn't make much difference, so keep it close to the fullrange drivers.
Black is the response on baffle with no filter, magenta is with a 9mH inductor in series. Also shown is impedance on the dashed lines. This shows that is you want the flattest bass response in a large room, you'll have to give up about 10dB in efficiency. That's typical. However, room gain will count for a lot, and you might end up with near 4mH for flattest low end. That room gain will help a lot. But it depends of course on your room and your placement of the baffles.
The second graph shows what the response might look like with room gain and the 4mH inductor.
Next you'll need to figure out what high pass is needed to put you 3dB down circa 450 hz. Nominally 44uF @ 8 ohms, but probably much less because of natural low end roll-off. That give you a first order crossover. If you feel that teh woofer is contributing to much up top, you can experiment with a large cap (~22uF) across the woofer. That will roll off the top end faster than just the inductor alone. I suggest buying a range of cap values from P.E. or Madisound to experiment with. Buy the non-polar electrolytic caps to experiment with, then figure out if you want to invest in $$$ caps when you settle on a value. Getting the value right is the most important thing. A nice film cap isn't going to sound good if it's the wrong value.
P.S. Just put the woofer in the center near the top. Moving it around on the baffle didn't make much difference, so keep it close to the fullrange drivers.
Attachments
musicbuff,
With regards to non-polar electrolytic caps, their tolerance can be easily 20% off the stated value so it's best to measure the value of the bipolar with a good digital LCR meter, (better still with Daytons Dats V3 if you have it on hand ) before selecting the final value.
This also helps with matching the values in the crossovers between the left and right loudspeakers. Fine tuning can be an ongoing process in OB design.
C.M
With regards to non-polar electrolytic caps, their tolerance can be easily 20% off the stated value so it's best to measure the value of the bipolar with a good digital LCR meter, (better still with Daytons Dats V3 if you have it on hand ) before selecting the final value.
This also helps with matching the values in the crossovers between the left and right loudspeakers. Fine tuning can be an ongoing process in OB design.
C.M
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