Hi,
I'm about to build tops similar to Peter Morris design Double 10 (soundforums) with some minor changes. Not completely sure how I'll build the box, in particular how to do a good solution for the front grille. Attached is two different designs, (both missing reflex ports). The tops will mainly be used as a portable PA, but might also double up as fronts in a home cinema
.
Parts:
BMS 4594HE 16 Ohm with BMS stock crossover C16-16
RCF HF950
B&C 10NDL64
I'll start with BMS crossover for the coax driver, but might go fully active later on. I have a db-mark xca48 for dsp, and a pkn xe2500 at the moment. Just tested the amp with the coax driver, and the hiss is quite loud. From what I've read, most class-D amps are quite hissy, or at least with such a high sensitive driver. I like the idea to be able to drive the tops with 1u 4ch lightweight amp, but if that means loud hiss, I'll probably ditch that thought. Anyone have suggestions on suitable amp for the driver? Or other tips on how to reduce hiss?
I'm about to build tops similar to Peter Morris design Double 10 (soundforums) with some minor changes. Not completely sure how I'll build the box, in particular how to do a good solution for the front grille. Attached is two different designs, (both missing reflex ports). The tops will mainly be used as a portable PA, but might also double up as fronts in a home cinema
.Parts:
BMS 4594HE 16 Ohm with BMS stock crossover C16-16
RCF HF950
B&C 10NDL64
I'll start with BMS crossover for the coax driver, but might go fully active later on. I have a db-mark xca48 for dsp, and a pkn xe2500 at the moment. Just tested the amp with the coax driver, and the hiss is quite loud. From what I've read, most class-D amps are quite hissy, or at least with such a high sensitive driver. I like the idea to be able to drive the tops with 1u 4ch lightweight amp, but if that means loud hiss, I'll probably ditch that thought. Anyone have suggestions on suitable amp for the driver? Or other tips on how to reduce hiss?
Attachments
I've been running some similar tops for a while. Same driver layout, different drivers, similar design challenges.
It's worth noting that the BMS crossover simply makes the two diaphragms work together as one. It doesn't do any response correction or anything like that. I'd keep it.
Here's what I used:
- 2x Faital Pro 10FH520
- 1x 18Sound ND1460 (jealous of your BMS driver!)
- 1x RCF HF94
Crossover is LR4 at 800Hz for 90% of gigs. If it's going to be loud, I go up to 1.2kHz to give the compression driver an easier time.
Amplifiers are Behringer iNukes at the moment, with ~1KW per 10" driver and 300w for the HF.
My boxes are standard cuboids with plenty of bracing. I used 4x bass reflex ports on the back of the cabinet. Each one is 3" diameter. I also came up with a way of blocking off up to three of the ports, which gives me a great deal of flexibility:
- With all four ports open, I get a 80Hz tuning frequency, and a lot of power handling. I run subwoofers to cover the low end, and find 4x 15"s a side to be a decent match for live music.
- With 2x ports open, the tuning drops to 60Hz and they'll still take a good deal of power. A little EQ is needed to get flat to 60Hz. You can run a rock band through them with decent results. The kick drum won't flap your trousers, but there's still some punch there. Fine for small venues.
- With 1x port open, tuning is 45Hz and even more EQ is needed. You can hit port chuffing with only one port open, but it's fine for when you want fairly deep bass in smaller venues.
For the grilles, I used some 12mm material glued to the baffle to stand the grille away from the drivers. Triangles in the bottom corners and between the two 10"s, and thin strips each side of the horn.
Good luck with the project!
Chris
It's worth noting that the BMS crossover simply makes the two diaphragms work together as one. It doesn't do any response correction or anything like that. I'd keep it.
Here's what I used:
- 2x Faital Pro 10FH520
- 1x 18Sound ND1460 (jealous of your BMS driver!)
- 1x RCF HF94
Crossover is LR4 at 800Hz for 90% of gigs. If it's going to be loud, I go up to 1.2kHz to give the compression driver an easier time.
Amplifiers are Behringer iNukes at the moment, with ~1KW per 10" driver and 300w for the HF.
My boxes are standard cuboids with plenty of bracing. I used 4x bass reflex ports on the back of the cabinet. Each one is 3" diameter. I also came up with a way of blocking off up to three of the ports, which gives me a great deal of flexibility:
- With all four ports open, I get a 80Hz tuning frequency, and a lot of power handling. I run subwoofers to cover the low end, and find 4x 15"s a side to be a decent match for live music.
- With 2x ports open, the tuning drops to 60Hz and they'll still take a good deal of power. A little EQ is needed to get flat to 60Hz. You can run a rock band through them with decent results. The kick drum won't flap your trousers, but there's still some punch there. Fine for small venues.
- With 1x port open, tuning is 45Hz and even more EQ is needed. You can hit port chuffing with only one port open, but it's fine for when you want fairly deep bass in smaller venues.
For the grilles, I used some 12mm material glued to the baffle to stand the grille away from the drivers. Triangles in the bottom corners and between the two 10"s, and thin strips each side of the horn.
Good luck with the project!
Chris
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Thanks for your reply! I've looked at your PA thread before, and it seems that you have designed a versatile system. I like your small subs, and I'm thinking of building something similar. I have two Tham15 but they are a bit heavy/big for me. Ideally I want a system that I can bring in a regular estate car.
My thought was to use two reflex ports on the front of the tops, tuned to about 65Hz. Side panels angled a bit to make the box more stable without need of massive bracing. The flexibility with four ports seems great, I'll probably do some simulations and see if that is something for me.
The BMS drivers are probably overkill for me regarding output, but I hope that I can at least take advantage of their sound quality. Tested the drivers with an old JVC receiver without any hiss/hum, so I might need to skip class-D amp for the drivers and look for something else.
My thought was to use two reflex ports on the front of the tops, tuned to about 65Hz. Side panels angled a bit to make the box more stable without need of massive bracing. The flexibility with four ports seems great, I'll probably do some simulations and see if that is something for me.
The BMS drivers are probably overkill for me regarding output, but I hope that I can at least take advantage of their sound quality
. Tested the drivers with an old JVC receiver without any hiss/hum, so I might need to skip class-D amp for the drivers and look for something else.
For what it's worth, I get 2x tops, 2x subs, amp rack and a few other bits in the back of a VW polo, and I can still see out the rear-view mirror. The bigger gigs with 4+ subs get a van rental added to the invoice unless it's just around the corner.
The new subs (~70L net, ported) are very good, but you need top-end drivers and a lot of power. I'm running an MA12000i on those.
The BMS units should sound very nice. I'm quite tempted to get a couple myself, but they certainly aren't cheap!
Chris
The new subs (~70L net, ported) are very good, but you need top-end drivers and a lot of power. I'm running an MA12000i on those.
The BMS units should sound very nice. I'm quite tempted to get a couple myself, but they certainly aren't cheap!
Chris
Hi, nice project ! I bet you really end up liking it.
I'm very familiar with the 4594HE on the HF-950, having built the Peter Morris PM-90. I've also been playing with that driver-horn combo on top of a double 12" box (just like the double 10" but using rcf 12n351) and on top bit more powerful single 12" rcf12n405.
I agree with what Chris says, especially about the crossover. It works fine and about the only time I really feel a need to biamp the driver is if it's gonna get pushed hard, and I want separate limiting control. The double 10"s will run out of gas before that happens...so all is good.
By the time you drop gain to the bms to match the 10"s, I'd expect most of the hiss to be gone. Good luck !
I'm very familiar with the 4594HE on the HF-950, having built the Peter Morris PM-90. I've also been playing with that driver-horn combo on top of a double 12" box (just like the double 10" but using rcf 12n351) and on top bit more powerful single 12" rcf12n405.
I agree with what Chris says, especially about the crossover. It works fine and about the only time I really feel a need to biamp the driver is if it's gonna get pushed hard, and I want separate limiting control. The double 10"s will run out of gas before that happens...so all is good.
By the time you drop gain to the bms to match the 10"s, I'd expect most of the hiss to be gone. Good luck !
chris - really nice to be able to fit such system in a polo .
Mark, thanks for your input. I've read both threads on the PM-90, that's what made me choose the 4594. But as I won't use that output I settled with double 10's.
I've now tested the drivers with different amps, PKN XE2500, Crown CDI-1000, old QSC USA 370. PKN has the most hiss (without input signal and output level at lowest), Crown has some. I can't hear any hiss from the QSC at all. Seems like the digital amps can't compete with an old class A/B amp. Of course the power output is in another league, but I won't need that much power for my drivers. I'll see if I can find any good lightweight class A/B amp (maybe Matrix XT800..). Or else test with a L-pad.
I've completed the cut sheet, so I hope to have some boxes ready within a couple of weeks.
.Mark, thanks for your input. I've read both threads on the PM-90, that's what made me choose the 4594. But as I won't use that output I settled with double 10's.
I've now tested the drivers with different amps, PKN XE2500, Crown CDI-1000, old QSC USA 370. PKN has the most hiss (without input signal and output level at lowest), Crown has some. I can't hear any hiss from the QSC at all. Seems like the digital amps can't compete with an old class A/B amp. Of course the power output is in another league, but I won't need that much power for my drivers. I'll see if I can find any good lightweight class A/B amp (maybe Matrix XT800..). Or else test with a L-pad.
I've completed the cut sheet, so I hope to have some boxes ready within a couple of weeks.
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