I'm thinking about starting my 2nd diy project: a sub. The goal with this project is not 'WOAH' sound but something that will provide some ok bass. I also didn't want it to be really expensive so that's why I'm not thinking about 500W subs. I'm thinking about this speaker here:
http://daytonaudio.com/files/specs/SD270-88_specsheet.pdf
It's only 51$ on Parts express and it's the one that seemed the best when I used on WinISD. It will be powered by a 70W sub amp:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-784
With this amp I thought of also powering my frst diy project which are 2 8ohm MTM speakers.
The enclosure will be vented with two 1,75'' ports of 3,75'' long:
http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=260-407
Enclosure will be about 70 L or 2.4 cu ft (24'' tall x 16'' wide x 14,75'' deep) which seems massive size to me but I guess that's what happens with a 12'' driver.
Can anybody give me any feedback on this project? Is it ok or is it awful idea? any ameliorations? Also, how do I fill it? Do I simply use foam on the walls or I also need to fill with polyfill? If I make braces, do I just make a cross in the middle of the enclosure?
http://daytonaudio.com/files/specs/SD270-88_specsheet.pdf
It's only 51$ on Parts express and it's the one that seemed the best when I used on WinISD. It will be powered by a 70W sub amp:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-784
With this amp I thought of also powering my frst diy project which are 2 8ohm MTM speakers.
The enclosure will be vented with two 1,75'' ports of 3,75'' long:
http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=260-407
Enclosure will be about 70 L or 2.4 cu ft (24'' tall x 16'' wide x 14,75'' deep) which seems massive size to me but I guess that's what happens with a 12'' driver.
Can anybody give me any feedback on this project? Is it ok or is it awful idea? any ameliorations? Also, how do I fill it? Do I simply use foam on the walls or I also need to fill with polyfill? If I make braces, do I just make a cross in the middle of the enclosure?
How big of a room do you have?
It'll be a good start, but I have a single 12" with 250W and believe me, sometimes I wish I had a second for very bottom-heavy stuff.
If your budget can accommodate it, the Dayton Reference HF is a very nice driver
Yes, you want to brace the middle of the perpendicular sides.
It'll be a good start, but I have a single 12" with 250W and believe me, sometimes I wish I had a second for very bottom-heavy stuff.
If your budget can accommodate it, the Dayton Reference HF is a very nice driver
Yes, you want to brace the middle of the perpendicular sides.
don't know the exact size of the room but it's like a medium sized room. I was looking at The HF series from Dayton but then I would need a better amp and everything. Although they are pretty impressive and I would like one. Only thing is that I am the only bass amateur in this house so if I ever turn it up I'll get yelled at. That's why thought low power sub would be good and cheap. And also, what width would be the brace?
Good driver choice. I used the 8" version with good effect (2 of, sealed @42L, LT to 28Hz).
Brace as much as you can (within reason), as I still get some colouration at high volumes on the 2 unbraced panels of my subs (the panel measures 15" by9", and it visibly vibrates -before- the speakers bottom out.
It might be an idea to make the box smaller (and sealed) and add a Linkwitz circuit, but that has severe limitations on maximum volumes at really low frequencies (I can get a pair of DVC speakers (60Wrms per coil) to bottom out with a 50W amp, around 30Hz, but it is still loud enough to cover the house, so it might be worth a look for you.
Chris
Brace as much as you can (within reason), as I still get some colouration at high volumes on the 2 unbraced panels of my subs (the panel measures 15" by9", and it visibly vibrates -before- the speakers bottom out.
It might be an idea to make the box smaller (and sealed) and add a Linkwitz circuit, but that has severe limitations on maximum volumes at really low frequencies (I can get a pair of DVC speakers (60Wrms per coil) to bottom out with a 50W amp, around 30Hz, but it is still loud enough to cover the house, so it might be worth a look for you.
Chris
I'm not too much into making my own crossover since my first attempt wasn't too brilliant. Thanks for the advice Chris. Maybe I should take a look at the same speaker but in 10'' version. I don't know why I started out with the idea of 12'' but perhaps 10'' will allow me to go smaller and have about the same sound. 12'' Fs= 26Hz and Fs 10'' = 30Hz... Anyway, anyone have advice on the filling?
Hooray for modest sub builds! Many people go so big, I think there's a lot of quality that can be had from less titanic efforts.
I don't know if you have looked at MCM's sub amps, but I kinda like them over the PE choices for budget setups.
http://www.mcmelectronics.com/browse/Amplifier Modules/3831187
Also, I just got a F-1 from CSS and I'm loving it. Great for taking the low-end load off the mains, with higher fidelity than your average plate amp XO.
http://www.creativesound.ca/details.php?model=F-1
My understanding is that you don't need to sweat the stuffing too much, as the sub will only be reproducing sounds that wouldn't be absorbed much by stuffing anyway. I threw a package of fluff from my local hobby shop into mine just for the heck of it.
Did you say in your first post that you intend to power your main speakers off the sub amp? I don't think the plate amp works that way...
I don't know if you have looked at MCM's sub amps, but I kinda like them over the PE choices for budget setups.
http://www.mcmelectronics.com/browse/Amplifier Modules/3831187
Also, I just got a F-1 from CSS and I'm loving it. Great for taking the low-end load off the mains, with higher fidelity than your average plate amp XO.
http://www.creativesound.ca/details.php?model=F-1
My understanding is that you don't need to sweat the stuffing too much, as the sub will only be reproducing sounds that wouldn't be absorbed much by stuffing anyway. I threw a package of fluff from my local hobby shop into mine just for the heck of it.
Did you say in your first post that you intend to power your main speakers off the sub amp? I don't think the plate amp works that way...
AdamThorne said:
Well if you look at the amps image there's a 'TO Speakers' output... What does that do? and thanks a lot for the post!the only problem is : since I live in Canada And that in Canada there aren't many places that sell stuff I need that's why I'm ordering from the states. Ordering everything from one spot and sending it to the P.O. Box costs less since I only pay shipping once. But still that amp is really interesting for 70$!
How do you guys think this sub will sound?
I believe that the "To Speakers" section is for the speaker level input.
If you don't have an RCA out that you can feed into the "low level" input, you have to run your speaker wire into the "From Amplifier" input. Then you need to get the speaker level feed back out so that you can run it to your actual speakers.
The plate amp looks like a high impedence in the bass frequencies to your amplifier, so the plate amp is really doing the work there. At higher frequencies the cross over in the plate amp just sends the signal along to the main speakers.
If you don't have an RCA out that you can feed into the "low level" input, you have to run your speaker wire into the "From Amplifier" input. Then you need to get the speaker level feed back out so that you can run it to your actual speakers.
The plate amp looks like a high impedence in the bass frequencies to your amplifier, so the plate amp is really doing the work there. At higher frequencies the cross over in the plate amp just sends the signal along to the main speakers.
Glowbug said:I've been thinking about getting one of those. Really don't want the Fostexes stressed too much, they don't have a lot of "give" before Xmech, that's for sure
Yeah, I've got a pair of Fostex mains, and I didn't want them reproducing the low bass. I listen to a bunch of electronic music, so I wanted to filter that off of the fostex and send it to something capable of providing more impact. And I've got one of those little t-amp amplifiers, so I wanted to save it some work as well.
I was using the active cross section of the plate amp I'm running. The result was better dynamics and volume, more bass punch -- an improvement but also more grain and fatigue from the main channels. The Reckhorn fixes that nicely. It provides smoother main channel output, and does a better job of matching / integrating through the crossover region.
And at a pretty reasonable price, IMO. I'm very happy with mine, totally recommend it.
NOTE: it will decrease your total system gain. It's tweakable though. All through-hole stuff. I haven't messed with the insides yet.
Stuffing
I have messed around with stuffing (briefly) and I've found it can help in music with sweeps (you get strange internal cab reflections), and certain frequencies get highlighted and coloured. Bracing is better to fix this than stuffing, but stuffing can help, as it can spread the force of the speaker's vibrations and stop the cab signing along as much.
For the crossover, most plate amps have them, however, I got a cheap 50W/channel, added huge caps for the PSU, and butchered the tone controls for an active 2nd order LP filter. Going to bridge it some time.
All I can say is good luck, and make sure you brace it properly (no half measures).
Chris
I have messed around with stuffing (briefly) and I've found it can help in music with sweeps (you get strange internal cab reflections), and certain frequencies get highlighted and coloured. Bracing is better to fix this than stuffing, but stuffing can help, as it can spread the force of the speaker's vibrations and stop the cab signing along as much.
For the crossover, most plate amps have them, however, I got a cheap 50W/channel, added huge caps for the PSU, and butchered the tone controls for an active 2nd order LP filter. Going to bridge it some time.
All I can say is good luck, and make sure you brace it properly (no half measures).
Chris
Drawn up a quick diagram for you.
Feel free to ask about it.
Chris
Edit - note, this is fairly elaborate bracing, but it is very good at what it does (I used it for only one bit of my sub, which is why the other panels vibrate), and the panels braced are rock solid no matter what the volume.
Feel free to ask about it.
Chris
Edit - note, this is fairly elaborate bracing, but it is very good at what it does (I used it for only one bit of my sub, which is why the other panels vibrate), and the panels braced are rock solid no matter what the volume.
Attachments
If I understand this right... I need to make rectangle with a quarter of a circle (so it won't be in the way of the driver) And put it on each side of the enclosure to form a kind of half sphere behind the driver? this image is only 2D it would be the same the other way around ( vertically) is this about what it's supposed to be?
Attachments
Nearly. The part at the bottom of the brace would reach the bottom of the box, so all panels are braced together. But yes, the half sphere behind the driver is correct.
Chris
PS - sorry for the diagram before. This one is better.
PS (again) - I've gotta go now, so I'll have to reply in the morning (well, morning here anyway).
Chris
PS - sorry for the diagram before. This one is better.
PS (again) - I've gotta go now, so I'll have to reply in the morning (well, morning here anyway).
Attachments
fouchagalaga said:
http://web.archive.org/web/20021007....cyberglobe.net/caraudio/resources/fiberfill/
GM
Enclosure designs
Not to rain on any ones parade...but you guys are barking up the wrong tree.
Panel resonances in a cube shaped enclosure is all wrong...as the panels are all equidistant(sp?) the pressure waves are summing up.
Equal distances within an enclosure all conspire to sum up internal waves.
The so-called enclosure Acoustic ratio 0.7937:1:1.2599 is designed to cancel out pressure waves mathematically.(Or so I've heard)
Braces should be of an odd arrangement....say 7/11 ths...
The idea is to not have any duplicates of braceings.....keep it random.
Locating the driver on the front panel needs to be off-center..on both axises
A sealed system sounds best on paper as a ported designs falls off 24 Db below F3....as opposed to 12 Db for a sealed system.
-Advanced Speaker Systems-Master Publishing Inc.-Ray Alden with Joseph A. D'Appolito, PhD, Contributing Technical Editor---P.6 & 8.
________________________________________________Rick....
Not to rain on any ones parade...but you guys are barking up the wrong tree.
Panel resonances in a cube shaped enclosure is all wrong...as the panels are all equidistant(sp?) the pressure waves are summing up.
Equal distances within an enclosure all conspire to sum up internal waves.
The so-called enclosure Acoustic ratio 0.7937:1:1.2599 is designed to cancel out pressure waves mathematically.(Or so I've heard)
Braces should be of an odd arrangement....say 7/11 ths...
The idea is to not have any duplicates of braceings.....keep it random.
Locating the driver on the front panel needs to be off-center..on both axises
A sealed system sounds best on paper as a ported designs falls off 24 Db below F3....as opposed to 12 Db for a sealed system.
-Advanced Speaker Systems-Master Publishing Inc.-Ray Alden with Joseph A. D'Appolito, PhD, Contributing Technical Editor---P.6 & 8.
________________________________________________Rick....
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