I've started up a project to make a pair of subs based on the Audio Drive 12-300SB 12" driver (a modified Eminence LAB12, used by BK Electronics in their Monolith sub).
It's going to run each drive in independant enclosures, of a compact size as possible (room size is a big restriction currently), sealed with an off-board power amp. I currently have a Behringer BFD for room EQ, though am also likely to use a Linkwitz Transform circuit to bring up the bottom end.
I've started a thread over on the AVTalk forum, but will post on here too.
AVTalk Thread
The one issue I have encountered so far is that when I input the speaker parameters into WinISD Pro it disagrees with the Cms info.
Listed as 0.35mm/N by Audio Drive, but WinISD gives me 0.1977mm/N.
Specs:
Impedance: 4ohms
Power: 300W
SPL 1W/1M: 86dB
Fs: 23.5hz
Re: 3.7ohms
Le: 1.30 mH
Qms: 2.73
Qes: 0.416
Qts: 0.361
Vas: 61.6 Litres
Mms: 232g
Cms: 0.35mm/N
BL: 17.46 T/M
Sd: 468.7 cm2
Xmax: +/-7.5mm
I don't have any easy way of measuring the info myself.
It's going to run each drive in independant enclosures, of a compact size as possible (room size is a big restriction currently), sealed with an off-board power amp. I currently have a Behringer BFD for room EQ, though am also likely to use a Linkwitz Transform circuit to bring up the bottom end.
I've started a thread over on the AVTalk forum, but will post on here too.
AVTalk Thread
The one issue I have encountered so far is that when I input the speaker parameters into WinISD Pro it disagrees with the Cms info.
Listed as 0.35mm/N by Audio Drive, but WinISD gives me 0.1977mm/N.
Specs:
Impedance: 4ohms
Power: 300W
SPL 1W/1M: 86dB
Fs: 23.5hz
Re: 3.7ohms
Le: 1.30 mH
Qms: 2.73
Qes: 0.416
Qts: 0.361
Vas: 61.6 Litres
Mms: 232g
Cms: 0.35mm/N
BL: 17.46 T/M
Sd: 468.7 cm2
Xmax: +/-7.5mm
I don't have any easy way of measuring the info myself.
A few design images, for those who like that sort of thing; like me!
My old RTP-15 sub and the correctly scaled new design (one of).
The pair next to each other.
The pair stacked, for use in my current small room.
My old RTP-15 sub and the correctly scaled new design (one of).
An externally hosted image should be here but it was not working when we last tested it.
The pair next to each other.
An externally hosted image should be here but it was not working when we last tested it.
The pair stacked, for use in my current small room.
An externally hosted image should be here but it was not working when we last tested it.
On checking with BK it would appear that the 0.35mm/N is a data entry error and the 0.1977mm/N should be used.
Many thanks to Baz for being prompt with his reply.
Many thanks to Baz for being prompt with his reply.
2 sealed will be nice, I look forward to the results.
These really do gain from porting, dual Monolith anyone? 5.5-6.5 cubes tuned to 20hz would be fantastic!
These really do gain from porting, dual Monolith anyone? 5.5-6.5 cubes tuned to 20hz would be fantastic!
If I had the room to house them I'd probably go down the ported route.🙂
As it is I'm currently sorting out small deatils, connectors etc to use, and getting a cost to have the cabinet parts cut properly. If I did them myself it would probbaly cost just as much, and also ages of time, to get the spare materials and tooling.
Should be fun. I'm needing to do some cabinet finish tests soon.😀
As it is I'm currently sorting out small deatils, connectors etc to use, and getting a cost to have the cabinet parts cut properly. If I did them myself it would probbaly cost just as much, and also ages of time, to get the spare materials and tooling.
Should be fun. I'm needing to do some cabinet finish tests soon.😀
My only concern with side firing the drivers is that the cabinets may 'walk'. Otherwise looks like a nice project. I can put you in touch with a company that can cut and router the panels if you want.
richie00boy said:
Most of the time well contructed solid enclosures don't do this.
Some tips! If they do move then a square or cross of velcrow will stop this on carpet.
If on wood or slippy surface like tile then rubber strips or weather stripping or some cured silicone sealed ridges will stop it.
There always a solution.
The cabinet will have decent feet of some sort to ensure they stay put. The current surface they have to contend with is carpet, and it is likely to stay that way when I move house, so pobably some good spikes for now.
I've not had any issues with walking cabinets on sub projects, as they're pretty heavy, well braced enclosures, normally ending up on spikes for the carpet. The upper of the 2 when stacked with gain some 'rubber feet', not sure exactly what yet.
richie00boy, if you could email me the company/contact that would be much appreciated.
I've not had any issues with walking cabinets on sub projects, as they're pretty heavy, well braced enclosures, normally ending up on spikes for the carpet. The upper of the 2 when stacked with gain some 'rubber feet', not sure exactly what yet.
richie00boy, if you could email me the company/contact that would be much appreciated.
Some more recent pics (these are on the AVTalk forum already).
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 an observation, but the U part of the horizontal brace probably will not do much. If it is porportioned correctly in the drawing it looks like there is only 1/2"-3/4" there. This will do little to brace the side, or front wall.
Although that looks to be 1" material you are using so the cabinet may be dampened enough anyway. Other than that it looks to be a nice project.
Although that looks to be 1" material you are using so the cabinet may be dampened enough anyway. Other than that it looks to be a nice project.
I have my sealed subwoofers decoupled from the floor by floating them on a pair of bicycle innertubes. This is wonderful for my apartment because it doesnt transmit as much vibration to the neighbors but it also doesnt vibrate the floor which improves bass clarity and integration. I wont go back to rigid feet. As for sealed over ported, I really like my sealed boxes. I put them directly behind my couch to gain sensitivity that i could use to LT them later! : )
Good project!
Good project!
The outer walls are 25mm MDF, the inner brace has been drawn to 20mm size, though likely will be 19mm. The actual 'holes' in the bracing will probably change as these were really just to get an idea of look and layout.🙂
I can tell you now that 25mm alone is not enough to avoid vibration! Not if you have high standards anyway. The bracing will be needed.
You should use 2 layers of MDF glued together. Imporves sound quality.
The distance between the inner braces and the outer walls should be less than 15cm, otherwise the cabinet walls will have reasonances.
Damping: one layer felt and one layer of a different damping material.
The distance between the inner braces and the outer walls should be less than 15cm, otherwise the cabinet walls will have reasonances.
Damping: one layer felt and one layer of a different damping material.
I just remembered another tip, grip matts like what you use on a car dashboard from any cheap shop are also good if you don't want to mark your subwoofer at all 🙂
Hi Retro
What internal volume (less driver volume) are you going to use?
Are you planning on adding a LT circuit?
If so, I might piggyback your build, as I am new to sub design and would prefer benefitting from the experience of others.
Best wishes
What internal volume (less driver volume) are you going to use?
Are you planning on adding a LT circuit?
If so, I might piggyback your build, as I am new to sub design and would prefer benefitting from the experience of others.
Best wishes
The volume is limited by the space that the enclosure can currently fit into, which is currently giving about 35L. I am looking at adding LT afterwards, but that is something I will be requring some help with myself. 🙂
One thing I hadn't mentioned is that these will by used in a system alongside a set of Jamo THX Ultra speakers, namely the D6 LCR (x3) and D6 SURR (x2). Electronics is currently a Denon AVR-2800 DD/dts receiver of 1999 vintage.
For amplification of the subs I amp looking at using an Alesis RA500 studio power amp (this is a power to cost ratio thing, ie i can't afford anything more currently). They'll be handling everything on 5.1 sountrack above 80Hz and all the LFE channel information.
For amplification of the subs I amp looking at using an Alesis RA500 studio power amp (this is a power to cost ratio thing, ie i can't afford anything more currently). They'll be handling everything on 5.1 sountrack above 80Hz and all the LFE channel information.
richie00boy said:
With 2 drivers, taking advantage of push-push loading is always worth considering. They can be in one box or one box with 2 compartments, as long as the drivers are rigidly coupled.
dave
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