BlackCatSound said:
Yep, Volt rate their drivers fairly conservatively. I was laughing when Bill told me about you running the Volts so hard and they still came out untouched. I doubt many drivers would have stood that sort of punishment.
No doubt the Volt's PMC use are bespoke stuff.
They also use a 15" version in a rather large transmission line:
http://www.pmcloudspeaker.com/xb3.html
CRT Projectors had one of these in their demo room driven by a large Bryston amp alongside IB1 speakers all around and a Barco Cine 9 CRT projector. That was a very serious system but I felt the bass was a bit much for the room size, some EQ would have definitely benefitted it. It did seem to reach low though, easily to 20hz and probably lower than that.
Hell, the IB1's alone sounded like they didn't need a sub.
ScottG said:
Yep, its the mid so it is a bit deceptive.
The BMS stuff has always looked good to me, unfortunately no one deals with it over here. I looked at the Planar Neo driver earlier this year, certainly interesting.
I've never heard one but apparently the Precision Devices line of drivers is very good too.
They've got a statement 21" driver that looks like it could offer a life changing experience if you can afford the room. Tony Gee is using a pair of these!
http://www.precisiondevices.co.uk/ShowDetails.asp?id=16
Scott,
Just a quick question:
Any particular preference for driver mounting? By that I mean should I place one to the front and one to the rear to cancel out some of the forces created by the drivers or should they be both forward firing?
I'm still pretty surprised by the predicted max SPL at 20hz when using 2 drivers in an 85ltr enclosure tuned to 20hz: 114dB. Then add the other sub for another +6dB and that's 120dB. Stick these two in my room and I've found I gain around another 5-6dB at 20hz from past experience.
That's a lot of SPL with plenty of headroom, I'm guessing a small amount of EQ will be needed but it shouldl only be slight.
I completely agree with you, this should be a very dynamic performer and the distortion will be extremely low at my usual listening level of 80-90dB thanks to the masses of headroom.
I'm looking forward to this 🙂
Just a quick question:
Any particular preference for driver mounting? By that I mean should I place one to the front and one to the rear to cancel out some of the forces created by the drivers or should they be both forward firing?
I'm still pretty surprised by the predicted max SPL at 20hz when using 2 drivers in an 85ltr enclosure tuned to 20hz: 114dB. Then add the other sub for another +6dB and that's 120dB. Stick these two in my room and I've found I gain around another 5-6dB at 20hz from past experience.
That's a lot of SPL with plenty of headroom, I'm guessing a small amount of EQ will be needed but it shouldl only be slight.
I completely agree with you, this should be a very dynamic performer and the distortion will be extremely low at my usual listening level of 80-90dB thanks to the masses of headroom.
I'm looking forward to this 🙂
2 drivers in a 85 ltr enclosure? Change the design? 😕
Holy cr@p! ..did you purchased 4 drivers? I was only talking about 2 (total)!
Can you get hold of your supplier and cut the order in half before he ships?
(..and here I thought the 700+ was an exageration.. I'm such a dumb@ss
)
If on the other hand you actually wanted that many - let me know. You could make 4 of the things and array them so that room modes are "swamped" at almost any position. (..that would be near the center of each wall in the room.)
Often driver coupling is used to reduce even order non-linear distortion. To make it really work well you need to actually couple the drivers together frame-to-frame, then 2nd order drops like a stone. It's not terribly usefull though unless the 2nd order spectrum dominates the response in the desired passband (i.e. is 10-15 db higher then 3rd). If its near the 3rd in level then it is kind'a pointless, after all - you would in effect simply have "exposed" 3rd order distortion. The problem here is that we don't know how the B&C driver operates distortion-wise.
Holy cr@p! ..did you purchased 4 drivers? I was only talking about 2 (total)!
Can you get hold of your supplier and cut the order in half before he ships?
(..and here I thought the 700+ was an exageration.. I'm such a dumb@ss
)If on the other hand you actually wanted that many - let me know. You could make 4 of the things and array them so that room modes are "swamped" at almost any position. (..that would be near the center of each wall in the room.)
Often driver coupling is used to reduce even order non-linear distortion. To make it really work well you need to actually couple the drivers together frame-to-frame, then 2nd order drops like a stone. It's not terribly usefull though unless the 2nd order spectrum dominates the response in the desired passband (i.e. is 10-15 db higher then 3rd). If its near the 3rd in level then it is kind'a pointless, after all - you would in effect simply have "exposed" 3rd order distortion. The problem here is that we don't know how the B&C driver operates distortion-wise.
ShinOBIWAN said:
I have a source. 🙂
I'll happily collect 2 of the B&Cs from Andy for you 😉 I'm down that way later today anyway.
ShinOBIWAN said:
I have one of those preparing to be installed in the car, hopefully it will do the business, I could knock up a home box and compare it to the ATC if you want to know how it does 😉
ScottG said:
LOL
No wonder I was so impressed with the figures.
Sorted it now.
I don't have room for 4 seperate 80-odd litre enclosures dotted around the room unfortunately. I thought you meant dual drivers in each of the stereo subs since you mention 2 drivers but obviously I mistook you. That's good anyway since I've just saved a fair amount of money.
What do you think to using 2 in a each sub anyway
BlackCatSound said:
Hi Tom
I was told that these were special order from manufacturer and weren't in stock. Not sure if I spoke to Andy or not when I placed the order.
If he has got them then feel free to take them and give them the same punishment you gave to the Radials 😀
Puggie said:
Hi Bill
Bit unfair 🙂
The 15" ATC would simply die, its good but I'm sure it ain't no match for that 21".
Geenius said:
Hi Tony
That's smaller than I expected, I'm guessing your using some EQ to get the extension down a little?
What do they sound like sealed?
Always impressed with your plan diagrams, what software do you use for that BTW? I use CorelDraw12 for the 2d stuff but its not really suited and the scale requires you to work in mm and then convert to cm for your cutting diagram, this means half your time is spent zooming in and messing around with nodes.
ShinOBIWAN said:
That's good anyway since I've just saved a fair amount of money.
What do you think to using 2 in a each sub anyway
Ah.. good 179 X2 is MUCH better than 179 X4! 😉
(besides you'll need the spare coin for the amp and that velodyne crossover
)Actually if you still have the behringer crossover you might be able to use it rather effectivly here (instead of something like the veledyne).
extra drivers
do you want to double the size of the enclosures? ..oh and remember interior volume is 63 ltr's (each), but that doesn't mean that the cabinets won't be considerably larger than this volume suggests.. I haven't go over mass damping the box yet
😀additionally this is still a mono design, the subs will be paralleled together.
ScottG said:Ah.. good 179 X2 is MUCH better than 179 X4! 😉
(besides you'll need the spare coin for the amp and that velodyne crossover
Actually if you still have the behringer crossover you might be able to use it rather effectivly here (instead of something like the veledyne).
My source is exclusively a PC and nothing else, from that I play uncompressed bit perfect copies, DVD's or whatever else. This is then passed via balanced digital signal to the DEQX.
I've got room correction done by DRC on the PC already, I could simply create a new correction filter for the sub and for-go the external box of tricks such as the Behringer or Velo. The added bonus is that DRC is more comprehensive and time/amplitude based.
extra drivers
..oh and remember interior volume is 63 ltr's (each), but that doesn't mean that the cabinets won't be considerably larger than this volume suggests.. I haven't go over mass damping the box yet
additionally this is still a mono design, the subs will be paralleled together. [/B]
Well since the sub will be mono, how about 2 drivers mounted in a single enclosure? This will virtually halve the amount of construction time and that is a very good thing with me 😉
I was thinking about powering them with something like a UCD700 for each.
ShinOBIWAN said:
1 cabinet would compromise performance (perhaps significantly depending on the design) and would become ludicrously heavy. Additionally it wouldn't give you the option for different placement for a better match to your room (if you decided to go that route at some time in the future). Finally, I don't think you would get the esthetic you are looking for (..the ones posted). BTW, I couldn't find those renderings you posted.. what page?
None of this however means that it can't be done, I think the biggest limitation here is placement in the room, and esthetics..
For instance you could go the "bipole" route you mentioned before with a slight improvement in performance if the frames were tightly coupled - but:
1. at best you will only get that directed compression feeling from 1 driver as opposed to two (..that forward radiation provides),
2. you will need to essentially place the sub well away from any wall because of the "rear" driver.
If you wanted to change the esthetics a LOT, then I could easily see something like an "end" or "coffee" table look composed of 2 basic rectangles with both the drivers AND the ports "compound" loaded to reduce even order distortion (..but this would be at the expense of 6 db because of a lack of floor loading the ports).
..and of course there are numerous varieties of designs that could also be explored (..each with their own advantages and disadvantages).
I'm game for anything - so if you are interested then ask away. Note though that I wouldn't be surpised if just a single cabinet when completely finished weighed in at around 115 kilos or more.
amps...
The UCD700 sounds good IF the power supply you make for it *easily* exceeds the maximum current value, otherwise it will still be clean and powerfull sounding - but likely a bit rounded and "fat" (..at least in comparison).
(I'd actually like to see a non-balanced 3-phase ("star" configuration) design with a choke loaded input for the power supply if possible - which would allow for a much smaller capacitance bank and an extremely linear/low noise "fast" DC output. ..Yeah, wishfull thinking.)
Final note: more amps means more current on tap which again makes for more "solid" "damped" bass. On the other hand the output impeadance will be higher and there will be a net loss of 3 db vs. the single amp parallel route. Frankly IF you have a *really* good supply for the UCD700 then I would just stick with one amp and parallel connect the drivers (..but thats just me).
ShinOBIWAN said:
I've also been playing around with enclosure shapes and was considering a sort of matching style to the Percieves:
It looks a little odd but I thought the same about the Percieves and they turned out nice. I also had the thought of a satallite enclosure on top of the sub which perform center channel duties but I don't really believe I need a center TBH but given the width of the sub its a possibility to do a vertical TM flanked by 6" woofers so as to avoid the horizontal MTM.
..and here they are.
Member
Joined 2002
Why do you need 2 subs ? Why not one nice 10" sub or 2 x 10" subs. Im planning to build a pair of subs using 8" Drivers Or ill buy a single 10" and have it ported. I don't need a sub but sometimes when i'm listening to tunes i like that extra kick ( or when people are loud up stairs 🙂
ScottG said:
Cheers Scott for clarifying things a little more. I've now got a good idea of where I want to take this.
I'll stick with 1 driver per cabinet.
I've got 2 of these drivers on the way but I think I'm only going to build one cabinet to start off with, 2 is large investment in time if I'm reading into your 'heavy' construction idea correctly. This way if I don't like them I won't have spent months constructing them.
I've decided to not do a matching sub but just keep it a simple but effective rectangle, I will of course still finish it in black and silver but I feel that the odd shape consumes much space for the given volume - the internal volume on the bass cabinets for the Perceive is only 55ltrs but takes up a rather large amount of space thanks to the void behind the 45 degree angle. Doing the same for a sub would be even worse I feel and likely mean a huge enclosure.
Right, down to the small details now:
You suggest a 63ltr enclosure tuned to 19hz, I've modelled this and it looks good. Is there any advantage to making it 85ltrs? This gives around another 2dB more output but group delay and phase around the port tuning are worse - percieved slow bass? I'm sure you had your reasons when you chose 63ltrs, I was just wondering if you could go into some depth.
Cabinet construction; we've already settled on a 7.2cm(same depth as the Perceive baffles) concrete baffle but what about box construction? I'm guessing that 18mm + 9mm MDF + 4mm lead bitumen sheets isn't good enough for the cabinet walls? What about a bracing - for the Percieves I used a kind of interlocking bracing with sub-divided panels then skinned the entire outer enclosure in 9mm MDF, these photo's better explain:
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Is this substantial enough or do we need something better suited for subwoofer duties?
I did have some other questions but its late now and need sleep, will come back tommorow and finish.
Cheers
Ant
Following the design with interest, I see you didn't like my emailed suggestions Ant 
😉
Just coming from a point of having built something very similar to this before, I think you are going to see real difficulties tuning a 63 litre box to 19 Hz without having a noisy vent. You'd have to go with a maximum of a 75mm vent to even fit it in the box - even that is 53cm long. A 63mm vent would be too small.
😉Just coming from a point of having built something very similar to this before, I think you are going to see real difficulties tuning a 63 litre box to 19 Hz without having a noisy vent. You'd have to go with a maximum of a 75mm vent to even fit it in the box - even that is 53cm long. A 63mm vent would be too small.
ShinOBIWAN said:
The ATC will never have the output of the PD, I'm more interested in comparing the SQ, if the ATC ends up in my living room (pretty likely) then it will have more output that the neighbous will ever need anyway.
Puggie said:
I can't imagine you being disappointed with the SQ. To be completely honest I was expecting something really special and got my expectations up a little too much, certainly good but my ears didn't quite have the orgasm that I had with other ATC drivers I've tried. I guess much is down to the box and loading, I probably didn't have it right and there's more to be had; I tried two configs, one was a sealed 110ltr enclosure with LT and the other was the same enclosure but with the port unblocked and tuned to ~25hz. The real problem is that the driver needs a huge enclosure of around 250ltr to get down low with ported. I prefered the sealed with LT out of these two. The construction of the roughish test box would have been a factor too.
richie00boy said:Following the design with interest, I see you didn't like my emailed suggestions Ant
Just coming from a point of having built something very similar to this before, I think you are going to see real difficulties tuning a 63 litre box to 19 Hz without having a noisy vent. You'd have to go with a maximum of a 75mm vent to even fit it in the box - even that is 53cm long. A 63mm vent would be too small.
Naw, appreciate the advice just that I don't listen too good 😀
Thats a good point about the port and something I'd considered whilst sketching rough ideas out. It will most likely have to be slot loaded and snake a little if its going to downward fire as the max height of the subs is 55cm else they will foul the view to the projector screen, actually the screen is height adjustable but I don't fancy having to strain mine and other folks necks from staring up at the screen, right now its just at eye level whilst sitting and is comfortable to watch.
Damn these constraints.
I'm hoping that someone has a super elegant solution to this problem
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