Hi everyone,
Need some guidance and advice on crossover design for a good sounding 2 way PA build with Faital Pro 15PR400 and HF10AK - not sure which waveguide to use and open to suggestions. This is for a friend who needs it quickly for some upcoming events and he came to me because he couldn't find anything off the shelf (ie. JBL, EV, etc) that sounded decent. Since the two drivers I motioned have a big following on here, I figured they would be the perfect starting point. Of course I'm open to other combinations of parts if they're on the same level as the Faital drivers.
First off, i have to point out that I don't want to push the x-over point down too far even if it may hurt off axis response. I know many will disagree with me on this and I'm well aware of the consequences, but I'd rather have a more palatable midrange than a rougher, more aggressive sound specifically at higher SPL. Most of the better sounding PA stuff I've heard with a 1" CD was crossed over above 1.5k - again, I know this is not optimal for directivity but as I mentioned above, it’s the lesser evil to sensitive ears.
Getting back to the waveguide, I prefer something that isn't as deep and will acousically align the drivers. I like some of the Faital, B&C, 18 sound WGs and wanted to be in the 60 - 80 degree ball park. I obviously can't be too picky here since it has to fit in an existing limited space and it doesn't need to be a CD WG either. I like the way a tractrix or expo WG sounds on the top end, but again open to suggestions as this dictates crossover design.
The existing cab specs are -
Enclosure volume - 66 liters (yes, its small)
Baffle dimensions - 16" w x 24" h
Existing WG cutout - 10.625" w x 6.125" h (can make adapter plate if smaller)
Max WG outer dimensions - 14.5" w x 7.25" h
Box will be sealed for use in conjunction with subs, so LF cutoff is not so critical.
Being that the enclosures are so small, I may end up with a fairly high system Q, which is ok since its for PA and will only be used with subs. I was also looking at other 15 inch drivers like the B&C 15NDL88, but prefered the 15PR400 and HF10AK mainly because they sound great and have a good reputation on here, plus alot of you have already have worked with them. I'm just was hoping to use a proven crossover design so I dont have to spend days designing an x-over since my life is crazy right now due to health issues. This may be my last speaker project.
Need some guidance and advice on crossover design for a good sounding 2 way PA build with Faital Pro 15PR400 and HF10AK - not sure which waveguide to use and open to suggestions. This is for a friend who needs it quickly for some upcoming events and he came to me because he couldn't find anything off the shelf (ie. JBL, EV, etc) that sounded decent. Since the two drivers I motioned have a big following on here, I figured they would be the perfect starting point. Of course I'm open to other combinations of parts if they're on the same level as the Faital drivers.
First off, i have to point out that I don't want to push the x-over point down too far even if it may hurt off axis response. I know many will disagree with me on this and I'm well aware of the consequences, but I'd rather have a more palatable midrange than a rougher, more aggressive sound specifically at higher SPL. Most of the better sounding PA stuff I've heard with a 1" CD was crossed over above 1.5k - again, I know this is not optimal for directivity but as I mentioned above, it’s the lesser evil to sensitive ears.
Getting back to the waveguide, I prefer something that isn't as deep and will acousically align the drivers. I like some of the Faital, B&C, 18 sound WGs and wanted to be in the 60 - 80 degree ball park. I obviously can't be too picky here since it has to fit in an existing limited space and it doesn't need to be a CD WG either. I like the way a tractrix or expo WG sounds on the top end, but again open to suggestions as this dictates crossover design.
The existing cab specs are -
Enclosure volume - 66 liters (yes, its small)
Baffle dimensions - 16" w x 24" h
Existing WG cutout - 10.625" w x 6.125" h (can make adapter plate if smaller)
Max WG outer dimensions - 14.5" w x 7.25" h
Box will be sealed for use in conjunction with subs, so LF cutoff is not so critical.
Being that the enclosures are so small, I may end up with a fairly high system Q, which is ok since its for PA and will only be used with subs. I was also looking at other 15 inch drivers like the B&C 15NDL88, but prefered the 15PR400 and HF10AK mainly because they sound great and have a good reputation on here, plus alot of you have already have worked with them. I'm just was hoping to use a proven crossover design so I dont have to spend days designing an x-over since my life is crazy right now due to health issues. This may be my last speaker project.
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Wayne Parham's 4 Pi speaker is what you need to look at for inspiration ( at the very least ).
- Google Pi Speakers for a link to his website.
The closer you come to following Wayne's well trodden path, the easier you'll make it on yourself.
To that end, buy ( from Wayne ) a pair of his custom H290C waveguides as well as a pair of his crossover PCB's ( and then consider using a pair of used JBL 2226H woofers instead of the FaitalPro's ) .
Also, you're needlessly directing your friend to spend at least $100.00 extra ( per HF driver ) than is necessary these days ( for a good sounding PA HF driver > IMHO ). He must be made of money.
I would buy a pair a $90.00 Celestion CDX1-1745 ( mylar diaphragmed ) HF drivers as a substitute to Waynes suggested B&C de250 or JBL 2426H drivers ( the Celestion's are close enough to the B&C's ).
- QSC uses these Celestion drivers ( in an OEM form ) within their well liked and well established self-powered speaker lines ( KW122, etc. ).
Wayne has a 3x3 ( 18db per leg ) crossover design that's all worked out for the H290C and is already to go .
- If you use it, you'll want to release a couple db of padding from the horn circuit ( since the 4Pi is a 97db speaker system unlike the 99db FaitalPro ).
I really recommend contacting Wayne and directing some monies his way ( he's owed it for all his Bespoke work if you were to go that direction).
- Google Pi Speakers for a link to his website.
The closer you come to following Wayne's well trodden path, the easier you'll make it on yourself.
To that end, buy ( from Wayne ) a pair of his custom H290C waveguides as well as a pair of his crossover PCB's ( and then consider using a pair of used JBL 2226H woofers instead of the FaitalPro's ) .
Also, you're needlessly directing your friend to spend at least $100.00 extra ( per HF driver ) than is necessary these days ( for a good sounding PA HF driver > IMHO ). He must be made of money.
I would buy a pair a $90.00 Celestion CDX1-1745 ( mylar diaphragmed ) HF drivers as a substitute to Waynes suggested B&C de250 or JBL 2426H drivers ( the Celestion's are close enough to the B&C's ).
- QSC uses these Celestion drivers ( in an OEM form ) within their well liked and well established self-powered speaker lines ( KW122, etc. ).
Wayne has a 3x3 ( 18db per leg ) crossover design that's all worked out for the H290C and is already to go .
- If you use it, you'll want to release a couple db of padding from the horn circuit ( since the 4Pi is a 97db speaker system unlike the 99db FaitalPro ).
I really recommend contacting Wayne and directing some monies his way ( he's owed it for all his Bespoke work if you were to go that direction).
Looks like your working with two drivers that are pretty flexible. The 66l enclosure should be fine ... WinISD puts that @ a QTC of .7
Looks just right.
I've used the 15PR400 with a 4th order and 2nd order in the 1-1.3khz range. You shouldn't need to worry about break up with that driver. Simple to work with really.
Can't help too much with the HF driver though. Why not just use Faitals horn? Will probably be a good match for directivity w/15 in the range you're shooting for. Make your life easier.
Hope you feel better profiguy.
Looks just right.
I've used the 15PR400 with a 4th order and 2nd order in the 1-1.3khz range. You shouldn't need to worry about break up with that driver. Simple to work with really.
Can't help too much with the HF driver though. Why not just use Faitals horn? Will probably be a good match for directivity w/15 in the range you're shooting for. Make your life easier.
Hope you feel better profiguy.
Some notes:
- Sacrificing off-axis response in favour of on-axis "quality" is a bad move for PA: over 90% of the audience is off-axis. Given that, I'd want to put the crossover somewhere in the 1kHz area, and would advise a 1.4" exit compression driver with a 2.5-3" diaphragm.
- Acoustic time alignment (via a shallow horn) isn't necessary: the low-pass filter (assuming no FIR filtering) will delay the woofer further, so you can use a deeper horn.
FWIW, a deeper horn also plays into the directivity control towards the bottom of the bandwidth. The shape of the knee of each of the low- and high-pass filters all affect the (effective) time alignment at the crossover. Pinning it all on the horn and then picking something sub-optimal is likely to give poor results.
- Avoid sealed boxes for PA use. Imagine, for a moment, that it's not a speaker inside that box, but a 1000w electric heater. Speakers are inefficient (often less than 10%), so this analogy isn't a bad one. Now, where will all the heat go?
In a ported box, with some forced air movement, the air inside the cabinet can exchange heat with the outside world. Bonus if you have multiple ports and arrange for convection cooling.
In a sealed box, the hot air just gets hotter. That makes it harder for the driver to exhaust heat from the motor, and you can end up with fairly severe power compression in the longer term. If the operator pushes the faders to make up for the lost output, driver failure is almost certain.
A pair of ports that tune the box fairly low won't mess anything up in the crossover region, but will help the drivers stay cool.
I think that covers it for now.
Chris
- Sacrificing off-axis response in favour of on-axis "quality" is a bad move for PA: over 90% of the audience is off-axis. Given that, I'd want to put the crossover somewhere in the 1kHz area, and would advise a 1.4" exit compression driver with a 2.5-3" diaphragm.
- Acoustic time alignment (via a shallow horn) isn't necessary: the low-pass filter (assuming no FIR filtering) will delay the woofer further, so you can use a deeper horn.
FWIW, a deeper horn also plays into the directivity control towards the bottom of the bandwidth. The shape of the knee of each of the low- and high-pass filters all affect the (effective) time alignment at the crossover. Pinning it all on the horn and then picking something sub-optimal is likely to give poor results.
- Avoid sealed boxes for PA use. Imagine, for a moment, that it's not a speaker inside that box, but a 1000w electric heater. Speakers are inefficient (often less than 10%), so this analogy isn't a bad one. Now, where will all the heat go?
In a ported box, with some forced air movement, the air inside the cabinet can exchange heat with the outside world. Bonus if you have multiple ports and arrange for convection cooling.
In a sealed box, the hot air just gets hotter. That makes it harder for the driver to exhaust heat from the motor, and you can end up with fairly severe power compression in the longer term. If the operator pushes the faders to make up for the lost output, driver failure is almost certain.
A pair of ports that tune the box fairly low won't mess anything up in the crossover region, but will help the drivers stay cool.
I think that covers it for now.
Chris
Its normal to use active crossover in PA it will let you get more out of the box as you can limit the high and midbass separately and also any EQ cuts are adding to box headroom at that frequency. With DSP you also then don't have to worry about the time alignment so much as you have delay to do that. Crossover components are also relatively expensive so this isn't even a high cost option if your smart about what your buying. Amps are available with built in DSP if you want this to be 'plug and play'.
@Chris,
I missed that part about a "sealed box". I agree with your advice to go ported for cooling purposes.
Also ( I'm in agreement that ), a 2.5-3" diaphragmed compression driver will offer greater clarity ( especially when live music is involved ).
Which CD driver would you recommend ( as well as horn/waveguide ) for the purpose of reinforcing live-music ?
PS; I also Biamp anything related to supporting Public Address ( unless the job is primarily for Spoken-Voice ).
I missed that part about a "sealed box". I agree with your advice to go ported for cooling purposes.
Also ( I'm in agreement that ), a 2.5-3" diaphragmed compression driver will offer greater clarity ( especially when live music is involved ).
Which CD driver would you recommend ( as well as horn/waveguide ) for the purpose of reinforcing live-music ?
PS; I also Biamp anything related to supporting Public Address ( unless the job is primarily for Spoken-Voice ).
Earl,
My main PA speakers use 2x Faital 10FH520 and 1x 18Sound ND1460 on an RCF HF94 horn. Excellent results, with a lot of output from boxes that I can lift with one hand. I've had 85dBC-slow (103dB peak) at 280' and still sounding decent.
Other compression drivers are available, of course, but I'd say anything reasonably high-end from a reputable manufacturer will do just fine. Ditto the horn. I like the RCF HF horns, though: They're square (rotatable), nicely made, do the job they're supposed to, and come with 1" or 1.4" plates so you've got some flexibility.
In terms of bi-amping, for high-power situations, I'd always go for bi-amping. I did try to come up with a passive crossover for those cabinets, but there were serious concerns over the power handling of the low-pass inductor: I use an amp capable of delivering ~2200w for the pair of 10"s, and it's a 4ohm load. That's a lot of current.
However, I also have a smaller pair of speakers featuring 1x Faital 10HX230. I managed a passive crossover with 4x components that got them sounding decent. The crossover is somewhere around 2kHz, so the required components are also quite small and low-loss. Some EQ improves the sound, of course.
Being able to use a cabinet with a standard amp is useful. The bigger nudge in that direction, though, is for stage monitor use. When you've got 6-8x wedges around, that's quite a lot of amp channels to bi-amp them. So, I'll tend to use passive crossovers there.
Chris
My main PA speakers use 2x Faital 10FH520 and 1x 18Sound ND1460 on an RCF HF94 horn. Excellent results, with a lot of output from boxes that I can lift with one hand. I've had 85dBC-slow (103dB peak) at 280' and still sounding decent.
Other compression drivers are available, of course, but I'd say anything reasonably high-end from a reputable manufacturer will do just fine. Ditto the horn. I like the RCF HF horns, though: They're square (rotatable), nicely made, do the job they're supposed to, and come with 1" or 1.4" plates so you've got some flexibility.
In terms of bi-amping, for high-power situations, I'd always go for bi-amping. I did try to come up with a passive crossover for those cabinets, but there were serious concerns over the power handling of the low-pass inductor: I use an amp capable of delivering ~2200w for the pair of 10"s, and it's a 4ohm load. That's a lot of current.
However, I also have a smaller pair of speakers featuring 1x Faital 10HX230. I managed a passive crossover with 4x components that got them sounding decent. The crossover is somewhere around 2kHz, so the required components are also quite small and low-loss. Some EQ improves the sound, of course.
Being able to use a cabinet with a standard amp is useful. The bigger nudge in that direction, though, is for stage monitor use. When you've got 6-8x wedges around, that's quite a lot of amp channels to bi-amp them. So, I'll tend to use passive crossovers there.
Chris
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Thanks Chris for your response ( and info on your twin 10's ).
I had noticed those previously and had thought to myself just how much I liked your design. What I like about all your designs are ( is ) they are purpose designed and built for your specific market.
I made up 16 mini-traps more than 20 years back using JBL 2123's ( then 2012's ) with 2426H drivers on RCF 9041 biRadials. Great little delay boxes or voice only PA support.
I looked through your Web/Blog lots of neat stuff there ( I recommend that profiguy check it out before too long to gain some perspective about his advisers > us ).
I have an ancient D12(E) out of action with a broken VC wire ( I think ) > your experience gives me hope ( I just need some motivation ).
- My collection of Calrec mics dates from the late 70's ( to give you an idea of my retirement age ).
Cheers <> Earl
I had noticed those previously and had thought to myself just how much I liked your design. What I like about all your designs are ( is ) they are purpose designed and built for your specific market.
I made up 16 mini-traps more than 20 years back using JBL 2123's ( then 2012's ) with 2426H drivers on RCF 9041 biRadials. Great little delay boxes or voice only PA support.
I looked through your Web/Blog lots of neat stuff there ( I recommend that profiguy check it out before too long to gain some perspective about his advisers > us ).
I have an ancient D12(E) out of action with a broken VC wire ( I think ) > your experience gives me hope ( I just need some motivation ).
- My collection of Calrec mics dates from the late 70's ( to give you an idea of my retirement age ).
Cheers <> Earl
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Thanks guys for all the input. I try to keep an open mind to everything pointed out here. That being said, we all have our little quirks which make us who we are and like what we like.
The primary use of these speakers will be small format PA use. Its more an exercise of repurposing some existing cabs and that will always compromise things, not being a clean slate design.
I agree about using a larger VC driver and pushing down the xover point. I have limited experience with larger exit drivers other than some newer neo designs like the Faital HF1440 1.4" driver. Its a hell of a CD and can play pretty high for having a VC of its size. The only drawback is price, being around $440 a piece.
Crossover wise, I wanted a simpler integrated approach using a passive network to make things simpler. I personally use a DBX driverack venue 360 and it does a great job. The guy who this is for really fell in love with the treble of the HF10AK. Being its a 1 " driver, it won't compete with the output capabilities of the large drivers, but its top end is very good.
A sealed cab definitely can't handle as much thermal power as a ported one and I'm very much aware with the risks over heating the LF driver VC. What I've done in the past to help keep the VC cool in a sealed cab was venting the rear pole piece out the cab by means of a vent tube. It does mess with the enclosure tuning, but it forces air past the VC gap from the pressure difference. I havent killed a driver yet from excess power input.
The primary use of these speakers will be small format PA use. Its more an exercise of repurposing some existing cabs and that will always compromise things, not being a clean slate design.
I agree about using a larger VC driver and pushing down the xover point. I have limited experience with larger exit drivers other than some newer neo designs like the Faital HF1440 1.4" driver. Its a hell of a CD and can play pretty high for having a VC of its size. The only drawback is price, being around $440 a piece.
Crossover wise, I wanted a simpler integrated approach using a passive network to make things simpler. I personally use a DBX driverack venue 360 and it does a great job. The guy who this is for really fell in love with the treble of the HF10AK. Being its a 1 " driver, it won't compete with the output capabilities of the large drivers, but its top end is very good.
A sealed cab definitely can't handle as much thermal power as a ported one and I'm very much aware with the risks over heating the LF driver VC. What I've done in the past to help keep the VC cool in a sealed cab was venting the rear pole piece out the cab by means of a vent tube. It does mess with the enclosure tuning, but it forces air past the VC gap from the pressure difference. I havent killed a driver yet from excess power input.