I have a question about powering these subwoofers Ant is building.
Ant plans on using the UCD700 but are there slightly cheaper options say for under $300? How about $400? 500?
Would the beefy Parts Express HPSA1000 be up to the challenge? How about its power supply?
Last, what are some good crossover options specifically for the subwoofer?
Thanks
Ant plans on using the UCD700 but are there slightly cheaper options say for under $300? How about $400? 500?
Would the beefy Parts Express HPSA1000 be up to the challenge? How about its power supply?
Last, what are some good crossover options specifically for the subwoofer?
Thanks
How much is a UcD700? I would say it's stupid to skimp on the amp when you are driving high quality speakers that need a lot of power and control.
From what I've seen of every plate amp on the market (must have looked at them all over the past year or so!) their power supplies are nothing like up to the job of continuous duty, and a lot of the output stages are under-dimensioned as well.
From what I've seen of every plate amp on the market (must have looked at them all over the past year or so!) their power supplies are nothing like up to the job of continuous duty, and a lot of the output stages are under-dimensioned as well.
Any vented design will, as a rule, have worse impedance phase characteristics and dips than a sealed box. As to whether the individual driver has other characteristics such as high inductance or other motor characteristics, I'll confess that I haven't looked into it.
Given the cost of the drivers though and the reasoning behind choosing them and the design, I see it as a bit daft to skimp on amps which would at the end of the day be a smaller fraction of the overall cost of the subwoofer system.
Given the cost of the drivers though and the reasoning behind choosing them and the design, I see it as a bit daft to skimp on amps which would at the end of the day be a smaller fraction of the overall cost of the subwoofer system.
richie00boy said:
Hi Rich
A mono UcD700ST ran to just over £575 including case, amp, PSU, connectors and a 2000VA traffo.
The UcD's, PSU and connectors arrived yesterday, the case will be around another 2 weeks and the traffo should arrive tommorow hopefully. I plan to build that before starting the subs, will get some photo's up of the 16kg traffo 😀 and other bits.
I've got some photo's of the rather serious BC drivers that I've been meaning to put up. Will find them out and post shortly.
You've got to love pro audio drivers, no BS, solid engineering and big motor strength. The only thing that gets me is that once mounted in a cabinet the cones tend to look god aweful cheap, oh well it sorta lowers expectations from vistors 😀
BTW That's a serious vented pole piece on the B&C's. And the ATC's are there for size comparison, the ATC bass driver is a 9" model and the ATC midrange is 3".
BTW That's a serious vented pole piece on the B&C's. And the ATC's are there for size comparison, the ATC bass driver is a 9" model and the ATC midrange is 3".
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Just started to run them in and can't help but be impressed at how incredibly quiet the motor is when running a 15hz at a what must be around half xmax - I can't get them to go any higher on only 200w, if you switch it higher then the amp protect keeps tripping after a short while 😀 The manufacterer specs these as 1kw under AES testing and 2kw continuous so 200w was never going to push them.
Coming back to the motor noise; I've run the 15" ATC's and the 15" Volt's in exactly the same manner and no way was the motor as quiet on either of those as these B&C's. I can stick my ear right upto the pole piece and all I can hear is a faint flutter of air on a 15hz cycle - that flared pole piece vent is doing a good job on turbulance. In comparison the ATCs rattled around quite baddly with audible harmonics and a huff/puff type noise from the pole vent. The Volts were better but don't have the eeiry silence that B&C has.
Another thing that strikes me is that when you hit the audible cycles such as 20hz the tone is just pure, no audible harmonics or motor noise - and this with my ear right slap bang against the cone in free air, I've always found that running a driver in free air at inaudible cycles(15hz) and fairly hard always shows up nasties in the cone, generated harmonics and motor. Considering that once mounted in a box with associated gains this is going to be a very low distortion sub.
Obviously I can't comment on much else apart from the motor and pole venting is obviously very well designed and audible harmonics are nill using the power I have available so far.
So far Scott, it looks like an excellent call on this one. Have you worked with these before?
I've got to expedite my sub plans 🙂
Coming back to the motor noise; I've run the 15" ATC's and the 15" Volt's in exactly the same manner and no way was the motor as quiet on either of those as these B&C's. I can stick my ear right upto the pole piece and all I can hear is a faint flutter of air on a 15hz cycle - that flared pole piece vent is doing a good job on turbulance. In comparison the ATCs rattled around quite baddly with audible harmonics and a huff/puff type noise from the pole vent. The Volts were better but don't have the eeiry silence that B&C has.
Another thing that strikes me is that when you hit the audible cycles such as 20hz the tone is just pure, no audible harmonics or motor noise - and this with my ear right slap bang against the cone in free air, I've always found that running a driver in free air at inaudible cycles(15hz) and fairly hard always shows up nasties in the cone, generated harmonics and motor. Considering that once mounted in a box with associated gains this is going to be a very low distortion sub.
Obviously I can't comment on much else apart from the motor and pole venting is obviously very well designed and audible harmonics are nill using the power I have available so far.
So far Scott, it looks like an excellent call on this one. Have you worked with these before?
I've got to expedite my sub plans 🙂
Not too far off finishing those Ellam's.
Only started these on Monday with around 12 hours work put into them so they've come together fairly quickly. To be honest they are bit of a rush job and it shows on close inspection - the veneering is a bit suspect. I never intended these to be anything other than a small diversion and to use up some spare tweeters so no worries anyhow.
The old man saw that I'd sanded the veneer and wasn't impressed, apparently its a big no no. I've probably lost much of the beauty of the wood now but didn't realise that at the time.
Only started these on Monday with around 12 hours work put into them so they've come together fairly quickly. To be honest they are bit of a rush job and it shows on close inspection - the veneering is a bit suspect. I never intended these to be anything other than a small diversion and to use up some spare tweeters so no worries anyhow.
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The old man saw that I'd sanded the veneer and wasn't impressed, apparently its a big no no. I've probably lost much of the beauty of the wood now but didn't realise that at the time.
richie00boy said:
It doesn't would be the answer.
I used that iron on backing stuff and frankly its poor. The veneer I used is very slight rippled and the adhesive doesn't have the holding power to keep it down no matter how much heat or pressure I apply.
You can see the ripples better after some clearcoat:
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I should have used contact adhesive but choose the iron on stuff because I've never tried it before, though this will be the first and last time.
OK thanks. Was not convinced it would have been suitable for what we needed, you've proven the case.
How are you going to apply the contact adhesive? I've been told it should be sprayed for best results.
I've also been told you need a 'balancing' veneer on the other side to offset the shrinking action of the glue. Any thoughts on this? I'm not sure what glue they used so maybe it's related to glue type, or maybe they are just total perfectionist craftsmen?
How are you going to apply the contact adhesive? I've been told it should be sprayed for best results.
I've also been told you need a 'balancing' veneer on the other side to offset the shrinking action of the glue. Any thoughts on this? I'm not sure what glue they used so maybe it's related to glue type, or maybe they are just total perfectionist craftsmen?
Shin,
I've been practicing a big with veneer for my own project and here is what I've found:
Iron on backer and rubber cement are not rigid.. They will shring and wripple under the veneer..
After doing alot of reading I tried to use the iron/glue method. Since wood glue is rigid after hardening it can't ripple or warp and will hold the veneer perfectly flat.. The trick is how to apply it.. Since I didn't ahve the money for a vacume press i used the "Iron method".
1) Apply yellow wood glue to both the back of the veneer and the cabinet face. Make sure its very thin
2) Let it sit until its completely dry.
3) Place the veneer on the cabinet and "Iron" it on with a houshold iron. Make sure you start at one corner and "press" the wrinkles and bubbles out of the veneer.. PUSH DOWN HARD. Also, you will need something between the veneer and iron, I used an old t-shirt to keep the veneer from burning...
I'm still working on joining too sheets of veneer to make the seam look nice... right now I always end up with a "crack" thats pretty visible 🙁 If anyone knows how to bond them I would apreciate the input 😉
--Chris
I've been practicing a big with veneer for my own project and here is what I've found:
Iron on backer and rubber cement are not rigid.. They will shring and wripple under the veneer..
After doing alot of reading I tried to use the iron/glue method. Since wood glue is rigid after hardening it can't ripple or warp and will hold the veneer perfectly flat.. The trick is how to apply it.. Since I didn't ahve the money for a vacume press i used the "Iron method".
1) Apply yellow wood glue to both the back of the veneer and the cabinet face. Make sure its very thin
2) Let it sit until its completely dry.
3) Place the veneer on the cabinet and "Iron" it on with a houshold iron. Make sure you start at one corner and "press" the wrinkles and bubbles out of the veneer.. PUSH DOWN HARD. Also, you will need something between the veneer and iron, I used an old t-shirt to keep the veneer from burning...
I'm still working on joining too sheets of veneer to make the seam look nice... right now I always end up with a "crack" thats pretty visible 🙁 If anyone knows how to bond them I would apreciate the input 😉
--Chris
Seemless joint
You need a plate of wood with one edge 100% straight
Then you fixate the veneer to this plate, and with its edge that you want straight a little outside
Then you can draw a carpenters plane along the edge til you reach the straight edge of the wooden plate
If you dont know how to get a plane very sharp(razorlike), it might be possible to use sandpaper glued to a piece of wood instead
When both pieces of veneer are done you can glue them together with some paper - paper is sanded away when doing finish in the end
Man, I wonder if this is english at all
You need a plate of wood with one edge 100% straight
Then you fixate the veneer to this plate, and with its edge that you want straight a little outside
Then you can draw a carpenters plane along the edge til you reach the straight edge of the wooden plate
If you dont know how to get a plane very sharp(razorlike), it might be possible to use sandpaper glued to a piece of wood instead
When both pieces of veneer are done you can glue them together with some paper - paper is sanded away when doing finish in the end
Man, I wonder if this is english at all
Thanks Tinitus and DIY.
I don't normally do veneering as I suck at it, I'll likely give these up as a bad job since a raw MDF enclosure only looks marginally worse. I like spraying cabinets because I can get professional looking results, with veneering the opposite is true.
I don't normally do veneering as I suck at it, I'll likely give these up as a bad job since a raw MDF enclosure only looks marginally worse. I like spraying cabinets because I can get professional looking results, with veneering the opposite is true.
ShinOBIWAN said:
Excellent!
Nope, just picked them on spec.s alone (..fairly objective for me 😉 )
Remember plan, plan, plan - then build.
(Note: My internet connection recently turned to cr@p (nasty storm).. it could be several days until I get a stable connection, so if you don't "here" from me for a bit you'll know why.)
BTW, they do look nice.. 🙂 I even like the cones..😱 😀
Whoa, I modeled those B&C drivers in WinISD.... Why would you pick those to use as a SUB-woofer driver? They don't go very low at all in ANY alignment it seems...
m0tion said:
Trust me they go low. I was running them in yesterday and the performance was pretty exciting. Bearing in mind that I've had 15" ATC's, 15" Volts and Stryke AV15's before these little 12's then it takes something a little out of the ordinary to get me excited.
Its all in the implementation, the aim is to move away from driver resonance distortion by sacrificing output at the bottom end and using EQ to drop the upper range to level match to the output at 20hz. I say sacrificing, this design will still do a 80dB 1w/1m @ 20hz anechoic. Put it in my room and you can expect that to rise to around 85-86dB, then consider that the drivers handle 1000w continuous under strict AES 2 hour testing and your looking at a peak SPL figure at 20hz of 110dB anechoic/~115dB in-room. Then build two and your looking at 120dB+ inroom at 20hz. Is that enough? 😀
These are also primarily for music first and foremost with occasional movie use. Considering that I mostly listen at 90dB at the most and 120dB is perceived as 8 times louder than that, there's plenty of headroom.
Model the Tumult 15D2 in a 300ltr sealed enclosure and the BC 12TBX100 in ported 63ltr/19hz tune and look at the max SPL figures - they're identical at 20hz. And that's a 15" Tumult vs. a 12" pro driver.
m0tion said:
There are a lot of reasons to pick a driver beyond gain for a given freq..
Specifically I was looking for two *basic* properties in the design:
Low compression (..meaning a volume that easily exceeds the driver's VAS yet is still "small".)
A specific impeadance curve that fits within the low compression/small volume requirement. In this instance an operating passband that is mostly "mass" controlled and therefor current controlled - which all else equal is more linear operation. Moreover I wanted the driver in-box resonance above the passband as much as possible and then back down to that resistive impeadance that is "mass" controlled as quickly as possible.
In addition to those 2 requirements it needed LOTs of force.
Ultimatly for the given design it isn't that in-efficent for a system capable of extending to 17 Hz relative to other drivers.
Yes, the Dayton RS series are more eff. in a similar volume with a bass reflex, BUT they do not have nearly the force nor do they deal as well with the impeadance issue. Most importantly, Shin does not want a driver he can't get locally.
Scott:
I'm having a really tough time justifying the real estate needed to fully, or even partially, follow your cabinet vision.
I'm limited in height to 55cm as I've got a projector screen that would be otherwise obscured with a taller model, of course the port is already ~55cm long and with the 10cm sand + 36mm MFD required on each side its quickly becoming a box that occupies 160ltrs and fouls my view of the screen. I've got to make some rather drastic compromises to the design and more specifically, cut back on the massive inert construction idea.
I'd like to keep as much of your suggestions as possible but the cabinet walls are just going to be 2x 18mm MDF with heavy bracing. The port will remain as downfiring, stood off a couple of inch, onto a plinth.
Feel a bit gutted to not do the whole hog but its either this or build a single sub.
Any suggestions in light of this?
Cheers
Ant
I'm having a really tough time justifying the real estate needed to fully, or even partially, follow your cabinet vision.
I'm limited in height to 55cm as I've got a projector screen that would be otherwise obscured with a taller model, of course the port is already ~55cm long and with the 10cm sand + 36mm MFD required on each side its quickly becoming a box that occupies 160ltrs and fouls my view of the screen. I've got to make some rather drastic compromises to the design and more specifically, cut back on the massive inert construction idea.
I'd like to keep as much of your suggestions as possible but the cabinet walls are just going to be 2x 18mm MDF with heavy bracing. The port will remain as downfiring, stood off a couple of inch, onto a plinth.
Feel a bit gutted to not do the whole hog but its either this or build a single sub.
Any suggestions in light of this?
Cheers
Ant
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