ultimate low cost FR system

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I don't think anything can compare to a fostex up to 10x the cost as far as the fostex drivers. This system I propose is not a true single driver system but I believe it makes more sense than TL or horns. The technology is there why not use it?

Start with a panasonic digital reciever SA-XR25,45,50,55,70. These are highly regarded.

Build a pair of fostex 167E's in a sealed enclosure of 8.6L F3 116hz.

Build a pair of small musical 8ohm subs. One sub under each of the fostex's (as stands.)

Set the speakers to small on the reciever with the crossover for the sub and fostex's @150hz.

From the sub out on the reciever connect a MCM 150W plate amp and connect the subs in parrallel.

It is so simple I have to ask why no one has done this?
 
I agree ideally the subs would get a stereo signal but that isn't possible with the panasonic digital recievers. I can't think of any way around it short of a preamp and then you are losing the digital path which makes the panasonic so special.

I think most recordings are mixed with bass in mono.
 
regal said:
It is so simple I have to ask why no one has done this?

ive seen it done, i just dont have any links. it seems to me that the FR is full of a lot more "purists" who dislike subs. they opt for TL's with limited range.

personally, i think building a pair of musical subs would blow the "low cost" budget by themselves. i have yet to hear an inexpensive subwoofer (of the 8", 150W variety) that sounds a whole lot better than a a good full range tower speaker.
 
regal said:
I agree ideally the subs would get a stereo signal but that isn't possible with the panasonic digital recievers. I can't think of any way around it short of a preamp and then you are losing the digital path which makes the panasonic so special.

I think most recordings are mixed with bass in mono.
Prevailing "wisdom" is that bass freqs contribute nothing to the stereo effect, I have heard recordings that disprove this.

Only on a 5.1 format would bass freqs be mixed to mono.

Do the Panasonics have tape-outs? Use those for the subwoofers. Run the FE167E full range.

But I agree, having two good subwoofers will not be economical. Maybe just run one.

Or perhaps a better solution is to put the FE167E in MJK's tapered TL design (originally for FE164). Bob Brines has plans for a folded version on his web site. Then cross over to a single subwoofer at a much lower frequency. IIRC not every commercial subwoofer would allow a 150Hz crossover point.

BTW I think the overall concept (full-rangers in sealed enclosures, plus actively amped stereo bass units) is a great idea, just not necessarily the most economical once you factor in the stereo subs.
 
partsexpress has a buyout of 8" DVC drivers that look "ok" for like $14 each. if you did that, a 150-watt plate amp for each, run them line-level out (not sub out), and cross them over with the fostex's, you might have a decent full range system on the cheap. however, i would opt for just doing a TL for the fostex's and having less bass, but much better bass. i cant imagine a $14 driver with 150-watts will be that great.
 
I have done some testing with my Fostex 127E and they really perform better when you actively cross them over 100hz or higher. These drivers are xmax limited so the higher you cross them over the better they sound.

I don't think the tape pre-outs on the panasonic reciever are fading (same output regardless the volume setting.)
 
instead of using the panny receiver, why not just build a complete 2-way active system? if you are doing powered subs, all you need to do is power the fostex drivers. they are pretty darn efficient, so that should be an issue. and, most of the plate amps out there give a line level output that can be used as your crossover. they have line in and then a line out that cuts the bass frequencies.

so, along your idea, you could use the output from a cd player to a passive volume control (or active) to the subwoofers, then out to the monitors, which would be powered with a gainclone or even a sonic impact T-amp or whatever.

IMO, some cheap powered monitors with powered subs hooked right up to a cd player could be the ultimate cheap FR system.
 
I'm just intend to do the same thing!!...with FE167E..but I'm still looking for good+sheep woofers..

I'm intend to build the FE167E-boxes in BR boxes....than they "can" work alone...even if the low frequence response are limited.

Edit: but configed as a complete 2-way active system.
 
Thanks for this thread. It's given me some ideas.

I believe the Panny XR55 has a bi-amp feature for two-channel playback. Why couldn't you use that to drive the subs? The only issue I see is that you would have to build your own low-pass filter for the subs, but at least you wouldn't have to buy plate amps.

Here's a link to the most comprehensive thread on the panny 55 that I have found. There is some discussion of bi-amping.

http://www.avsforum.com/avs-vb/showthread.php?t=530504

Doug
 
I think you'll have a hard time producing good, inexpensive bass. Good bass is inherrently expensive. A 'good deal' is a 12" sub for around $100. Fostex drivers are dirt cheap in comparison to the cost of what a good bass driver is. Really, they're a bargain unmatched by any subwoofer. Maybe someone knows of a subwoofer that would do justice to a pair of Fostex's for around $100 or less. I don't know of any. I know you can get subwoofers for cheap, but they generally aren't good at all.
 
True to a point, but I think the original poster said "musical sub." I'm guessing the inference is that they would be listening to music only, in which case 30-35hz should be perfectly acceptable. The big thing with subwoofers in the HT crowd is sub-20hz and loudness, which is not that important with music (unless you're really into organ music).

You would be surprised at how cheap old used woofers are. Some of them quite good, only needing refoaming. These would work great for music-only systems.

Doug
 
I think the idea is good, as I adopted very similar idea. Only diffrence is that I use Behringer digital crossover between the Pana and the Fostex FR (same as http://www.newformresearch.com/digital-amplifier-packages.htm)
I would still consider my system as low cost, except for the F200A)

In my case:
(1) Fostex F200A XO at 90Hz, sealed
(2) ScanSpeak woofers as stereo bass modules.
(3) Panasonic XR-45
(4) Behringer DCX2496

I just completed above project and I will try post pictures when I find the time.

LageB
 
LageB said:
I think the idea is good, as I adopted very similar idea. Only diffrence is that I use Behringer digital crossover between the Pana and the Fostex FR (same as http://www.newformresearch.com/digital-amplifier-packages.htm)
I would still consider my system as low cost, except for the F200A)

In my case:
(1) Fostex F200A XO at 90Hz, sealed
(2) ScanSpeak woofers as stereo bass modules.
(3) Panasonic XR-45
(4) Behringer DCX2496

I just completed above project and I will try post pictures when I find the time.

LageB
I think the Behringer XO is a great idea. My idea is to send a full-range signal to the full-range driver, let the Behringer unit feed the bass unit. You still get the time-alignment, and EQ in the bass freqs, but keep the full-range signal "pure".

On a separate note, I've read a lot of good things about the Yamaha servo-powered subs. One or two of those might represent a pretty low-cost bass solution.
 
I picked up a pair of 8" subwoofers from madisound for $20 each. F3 in a ported box is around 35hz which will be fine for music. I just need to find a good deal on a sub plate amp. The $50 MCM amp is sold out.

As far as using the biamp from the XR55 you wouldn't be able to use the highpass. Highpassing the fostex's anywhere from 100hz-200hz really makes them sing.

The only downside to this system is the bass below 150 is mono, I don't think that is a problem because the stereo effects from bass notes are usually at higher frequencies (overtones.)

If 150hz is too high the panasonic can also do a 100hz crossover. But that would require a BR enclosure for the Fostex instead of sealed. My understanding is subs integrate better to sealed mains.
 
Hi Regal,

I heartily agree with your premise. It would seem a very sensible budget solution. I have used a pair of XR25's downstream of a DCX2496 and a DEQ2496 to triamp a widerange (FE 168 Sigma or Stephens FR80) with sub-bass and high treble assist on big OBs. I can vouch both for the amplifiers and for the benefits of highpassing a Fostex.

Here's an idea for an even more frugal front end--the Koss KS5192. For about a hundred bucks, you get a receiver with --I believe-- the same TI amplification chipset as the XR series, plus a built-in multi-format CD/DVD transport.
 
regal said:
As far as using the biamp from the XR55 you wouldn't be able to use the highpass. Highpassing the fostex's anywhere from 100hz-200hz really makes them sing.

I've asked just such a question on AVS. If the Panny won't do it, why can't you put an external high pass on the Fostex's and a low pass on the subs? Sort of like a roll your own cheap Behringer, but perhaps the Behringer is the better solution.

Doug
 
Taperwood said:


I've asked just such a question on AVS. If the Panny won't do it, why can't you put an external high pass on the Fostex's and a low pass on the subs? Sort of like a roll your own cheap Behringer, but perhaps the Behringer is the better solution.

Doug


Do you mean with passives? It would require very large expensive capacitors and inductors.

If you mean active, this would mean using a DAC from the DVD/CDP which you don't want to do with the panny. With the panny in order to get the "special" sound you have to use the digital in which means no active xovers between it and the CDP.
 
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