I've got the urge to build something as an afternoon project, something I can use with my NAD 3020 as a backup system now that I've got the main rig glowing in the living room 
So I'm thinking about a pair of OB speakers. Where I'm using the NAD, I don't need a ton of efficiency like I would have with the triode amps. Problem is, I can't seem to find plans out there for simple OB speakers that use easily-found drivers. All the ones I see are for rare or very expensive ones
So what are some cheap, easy to find (@ Madisound, PE or elsewhere) speakers that have potential in OB? What size baffle should I start out with?
So I'm thinking about a pair of OB speakers. Where I'm using the NAD, I don't need a ton of efficiency like I would have with the triode amps. Problem is, I can't seem to find plans out there for simple OB speakers that use easily-found drivers. All the ones I see are for rare or very expensive ones
So what are some cheap, easy to find (@ Madisound, PE or elsewhere) speakers that have potential in OB? What size baffle should I start out with?
Either the Silver Iris or for true fullrange but less bass, the Visaton B200.Or any driver with qts of .7 or greater and a reasonably low Fs, say 50hz or less
For cheap find an old console stereo and get the speakers from that,I did it this about a month back with some 8 inch Rola drivers in 3 foot tall x 2 foot wide baffles and it works very well.
If you have the space try these-
http://members.myactv.net/~je2a3/open.htm
Check the Hawthorne Audio site forum, some discussion there regarding baffle building.
You can download a spread sheet here-
http://www.t-linespeakers.org/downloads.html
(baffle xls) and it will show the effect of different size baffles and different drivers on frequency response.
For cheap find an old console stereo and get the speakers from that,I did it this about a month back with some 8 inch Rola drivers in 3 foot tall x 2 foot wide baffles and it works very well.
If you have the space try these-
http://members.myactv.net/~je2a3/open.htm
Check the Hawthorne Audio site forum, some discussion there regarding baffle building.
You can download a spread sheet here-
http://www.t-linespeakers.org/downloads.html
(baffle xls) and it will show the effect of different size baffles and different drivers on frequency response.
"JE Labs" OBs..
I've built em and love em.
Do not alter the dimensions or location of the primary driver. But you can alter the back "shelf", making it full width (about 30" long) instead of 6" or so. Bass is improved.
As Mr. Esmilla suggests, finish (cosmetically) the loudspeakers before you listen to them, or you'll never take em apart to finish them
I've built em and love em.
Do not alter the dimensions or location of the primary driver. But you can alter the back "shelf", making it full width (about 30" long) instead of 6" or so. Bass is improved.
As Mr. Esmilla suggests, finish (cosmetically) the loudspeakers before you listen to them, or you'll never take em apart to finish them
The only thing that bothers me about the 15" Silver Iris's is the fact that people are saying the 10's are "faster"...now, I've been around this sort of thing long enough to know that inductance plays a larger part in transient response than Mms does, so what's going on here?
I just don't want to have sloppy midrange as a tradeoff for deeper bass. I can always add a small sub to take care of the sub-60Hz material.
I'd build the JE Labs version, except my room is a little small for that...not sure how well I could fit the baffles in there. A taller but narrower baffle would fit better.
I just don't want to have sloppy midrange as a tradeoff for deeper bass. I can always add a small sub to take care of the sub-60Hz material.
I'd build the JE Labs version, except my room is a little small for that...not sure how well I could fit the baffles in there. A taller but narrower baffle would fit better.
Have you thought about using one of the Fostex full range drivers, maybe a FE-167E, and a 15" HE woofer crossed over someplace between 100 and 200 Hz? Would not be too expensive and I have to believe very nice sounding. I think a full range driver and a big woofer makes a lot of sense. Baffle could be 20 to 24 inches wide by 40 to 48" tall with a pair of hinged wings.
Which woofers would you suggest?
I read a previous thread on here where Peerless SLS's were recommended: http://www.madisound.com/cgi-bin/index.cgi?cart_id=4932990.29248&pid=1946 but the Q seems a bit low.
I read a previous thread on here where Peerless SLS's were recommended: http://www.madisound.com/cgi-bin/index.cgi?cart_id=4932990.29248&pid=1946 but the Q seems a bit low.
I have not done any design work, but consider this combination as a starting point.
Full range driver = Fostex FE-167E or 166E, each is 94 dB efficient ($63 each)
15" Woofer = Eminence Alpha series 15A, each is 97dB efficient and Qts = 1.26 ($58 each)
or
15" Woofer = Eminence Beta series 15, each is 98dB efficient and Qts = 0.59 ($72 each)
Crossover = Behringer CX2310 ($90)
XLR Cables = six required ($50)
Total Cost = 2 x $63 + 2 x $58 + $90 + $50 = $382 plus wood.
I can say that a 15" woofer with a full range driver is extremely efficient and produces great dynamics. You can see my Project 7 for an example of this type of system. Again, I have done no design work but this looks to be a good starting point at a reasonable cost.
Full range driver = Fostex FE-167E or 166E, each is 94 dB efficient ($63 each)
15" Woofer = Eminence Alpha series 15A, each is 97dB efficient and Qts = 1.26 ($58 each)
or
15" Woofer = Eminence Beta series 15, each is 98dB efficient and Qts = 0.59 ($72 each)
Crossover = Behringer CX2310 ($90)
XLR Cables = six required ($50)
Total Cost = 2 x $63 + 2 x $58 + $90 + $50 = $382 plus wood.
I can say that a 15" woofer with a full range driver is extremely efficient and produces great dynamics. You can see my Project 7 for an example of this type of system. Again, I have done no design work but this looks to be a good starting point at a reasonable cost.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-455
Those look like a good candidate...
The only problem with going active is that I don't have the amp channels for it right now, and I'd like to stick with the integrated amp I do have for now.
Those look like a good candidate...
The only problem with going active is that I don't have the amp channels for it right now, and I'd like to stick with the integrated amp I do have for now.
So far, i'd classify most of the suggestions so far as medium expensive...
I'm reserving judgement on the Silver Iris 15 until i hear it with the new HGD XO. With the original XO i couldn't live with them. They do produce a wonderful, larger than life soundstage with a lot of bloom in the bass. The 10" will be interesting. The Visaton B200 i could live with (but can't afford).
If you want a truly cheap OB, you need to look at vintage recycled drivers. I have drawers of candidates (and could point to some of the more interesting ones that get onto eBay). With any open baffle the depth of the bass is largerly determined by the size of the baffle (althou JohninCR has done some interesting work with baffle shape). A high Q driver will have a more or less ideal baffle size which has OB cancellation in just the right place to lower the Q of the system. A higher Q driver will need a smaller baffle. To get real low bass you need to move a lot of air, and even for the 15" SI there is an auxilary woofer -- which gets us back to Martin's big/woofer, FR as midtweeter approach. To do this passively you need to get drivers with similar efficiency (not always easy) and XO above 200 Hz.
As a side note, when i was selling 3020s new, i sold quite a few with Quad 303s, PS Audios, Haflers, even NAIMs for use in bi-amped systems. A 3020 + a gainclone would be today's equivalent.
dave
I'm reserving judgement on the Silver Iris 15 until i hear it with the new HGD XO. With the original XO i couldn't live with them. They do produce a wonderful, larger than life soundstage with a lot of bloom in the bass. The 10" will be interesting. The Visaton B200 i could live with (but can't afford).
If you want a truly cheap OB, you need to look at vintage recycled drivers. I have drawers of candidates (and could point to some of the more interesting ones that get onto eBay). With any open baffle the depth of the bass is largerly determined by the size of the baffle (althou JohninCR has done some interesting work with baffle shape). A high Q driver will have a more or less ideal baffle size which has OB cancellation in just the right place to lower the Q of the system. A higher Q driver will need a smaller baffle. To get real low bass you need to move a lot of air, and even for the 15" SI there is an auxilary woofer -- which gets us back to Martin's big/woofer, FR as midtweeter approach. To do this passively you need to get drivers with similar efficiency (not always easy) and XO above 200 Hz.
As a side note, when i was selling 3020s new, i sold quite a few with Quad 303s, PS Audios, Haflers, even NAIMs for use in bi-amped systems. A 3020 + a gainclone would be today's equivalent.
dave
So one of these...http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-455
with one of these: http://www.madisound.com/pdf/fostexdrivers/FE167E.pdf
If I were to go passive, what frequency and slope should I be shooting for? I have no problem building my own Xovers, but figuring out where the drivers should be crossed at and how steep really isn't my thing
Thank you all for your help so far...immensely helpful
with one of these: http://www.madisound.com/pdf/fostexdrivers/FE167E.pdf
If I were to go passive, what frequency and slope should I be shooting for? I have no problem building my own Xovers, but figuring out where the drivers should be crossed at and how steep really isn't my thing
Thank you all for your help so far...immensely helpful
Glowbug said:So one of these...http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-455
with one of these: http://www.madisound.com/pdf/fostexdrivers/FE167E.pdf
If I were to go passive, what frequency and slope should I be shooting for? I have no problem building my own Xovers, but figuring out where the drivers should be crossed at and how steep really isn't my thing
For something like that i always consider a 1st order series XO 1st (check Andy Graddon's site).
And with an XO over 200 Hz, you could consider the FE166e as well, but considering the differences in the efficiency, and not wanting to burn as much power in a series R as in the FR itself, you would do well to consider FE127e instead (despite 92 dB claimed it is probably closer to the 90 specced for the woofer). It is also about half the price, and it gets way better once modded. Even stock it has an edge on the 167 thru the mids & top where it would be used.
dave
Glowbug said:So one of these...http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-455
with one of these: http://www.madisound.com/pdf/fostexdrivers/FE167E.pdf
If I were to go passive, what frequency and slope should I be shooting for? I have no problem building my own Xovers, but figuring out where the drivers should be crossed at and how steep really isn't my thing
Thank you all for your help so far...immensely helpful
You can't go passive with these drivers - the PE woofer is to low in eff. and fs..
Think of the PE woofer as an open baffle *powered* sub driver when used in pairs per channel.
Dave has the best idea at low cost.
Martin's suggestions are somewhat problematic for the lower and mid - midrange for a passive implementation unless the baffle is huge.. and I think thats what he is suggesting with the "wings".
There is one 15 inch driver that seems to be about right for the upper bass lower midrange in a passive implementation..
MJK... sorry If I mis-understood too...
I was just suggesting something that may be smaller than the "JE Labs" OB, that reportedly fit the bill for the thread author in terms of size (as in smaller baffle than the "JE Labs" dimmensioned OBs).
Here's perhaps something closer to what MJK and others have suggested as far as a taller, narrower baffle
I was just suggesting something that may be smaller than the "JE Labs" OB, that reportedly fit the bill for the thread author in terms of size (as in smaller baffle than the "JE Labs" dimmensioned OBs).
Here's perhaps something closer to what MJK and others have suggested as far as a taller, narrower baffle
OK, after playing with my MathCad OB worksheet for a few minutes, here is what I get for a response.
http://www.quarter-wave.com/OB_2_Drivers_5_09_06.pdf
This is a 40" tall and 24" wide baffle, looks pretty good to me.
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