Need suggestions and advice for stereo/HT setup

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Hello,

I'm planning a HT setup with 4ch DIY amp which will also double as primary stereo. I was thinking of Sachiko's as fronts and something much smaller (and as cheap as possible) as rears, bookshelf size, maybe something like Fonkens. Rears will be wall mounted, is there a horn design that small to resemble a bookshelf size (or close to it)?
The sub (and center) will have to wait few more months.

Amp is 41Hz Audio AMP9 rated at 4x50w rms, room is 36 m2 (118 square feet)

I was thinking Fostex FE207E for fronts (with pair of tweeters) and as cheap as I can go for rears. Will 4" suffice? Do I have to be worried about using same brand drivers for fronts and rears? Can voice matching problems occur?
Many questions...

Is my reasoning for the setup in general OK? Please do suggest anything you feel appropriate to change, what enclosure and what drivers to use in rear speakers, etc, anything.


Warning: I'm almost total noob in DIY and audio in general. But I've learned a lot reading much for the last few weeks, in places like this. Building will not be a problem, I have a hoby carpenter friend that will help with most of the constructon.
 
Couple of points,

The FE207E was discontinued by Fostex some months ago, so is unavailable unless you can find a dealer with some stock left over.

Sachiko (now obsolesecent) was designed with the FE206E in mind; the 207 will not work as well as the driver it was designed for.

'Small' and 'horn' is generally a bit of an oxymoron; you'd be better off with something rather less complicated if small size is desired.

36m^2 is not 118ft^2: it's 387.5ft^2 (1m^2 = 10.764ft^2) -which is the more accurate dimension; the m^2 or the ft^2 value? That's important because if your room only has an area of 118ft^2, then Sachiko will be too large to function properly. I'm guessing that your room does indeed have a floor area of 36m^2 & you accidentally used a length rather than an area conversion (as 36m is indeed = 118.1ft)

Whatever you build, avoid MDF if at all possible.

In an ideal world, the rear channels would really need to have more dynamic BW than a 4in driver can typically provide. However, as we don't all live in an ideal world, compromise generally creeps in; luckily as rear channels do not generally have as demanding a job as the fronts, you can downsize these to an extent. You don't necessarily need to employ drive units from the same brand front & rear, although it can help.
 
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Tnx Scott, you're as helpful as always and believe me I've red a ton of your posts and not just in this forum. Talking to you feels like talking to a celebrity! (joking) :D

Yes, room is 36m^2, it seems that my conversion to feet was messed up.
So, MDF is no go (not to even mention the chipboard than)... kinda what I concluded after researching the subject of cabinet materials yesterday.
3/4" plywood all the way than? Even braces inside the cabinets?
Does furnishing the cabinet with something change anything in the sound?

FE206E and FE207E shouldn't share enclosures? I thought only difference was that 206 is a bit more sensitive and not shielded?
I wanted to use FE207E because ppl say it's a bit warmer sounding than the FE206E and it's a bit stronger on the low end. Also the 207 is shielded and front cabinets may be somewhat close to a 50" plasma display... Plasmas use fluorescent cells, can those be affected by the driver magnets? I know that's gas in those cells but still doesn't hurt to be careful... :) (was searching the net on this but with no conclusion)
Anyway, nothing is set on stone and any suggestions on drivers and enclosures are very welcome.
Cabinet size is (almost) of no concern as WOF is no problem (she even bigger movie aficionado than me) and space is abundant. Cost is somewhat important but I might indulge myself to overspend (the budget) on fronts.

About rears, is the voice matching that much of a problem?
I was thinking to go 4" because of the cost primarily and also because of the box size. But the latter is more flexible, only other requirement is that the box have to be wall mounted.
So should I go 6 ~ 6.5"? Suggestions on drivers and enclosures for rears, Fostex all the way or some cheaper drivers could do? (Pioneer B20, even though they're 8", comes in mind)
 
Depends on the ply. MDF is better than nothing at all, but isn't ideal for wide BW applications unless you can go to ludicrous thicknesses so is best employed for HF & midrange enclosures. Chipboard (particleboard) is somewhat more benign than MDF in terms of taming resonance, although unless you get a very high quality type it does crumble easily, so you need to be quite careful, especially when running the old hoover or Dyson around.

The 206 & 207 are not necessarily interchangable; note the different specs. for each. The 207, having a somewhat higher Qt than the 206, works better in typical vented alignments cabinets where the 206 may be overdamped.

A plasma or LCD TV shouldn't be affected by unshielded speakers -I suspect the proliferation of these devices over the past few years & the decline of the CRT was the reason Fostex killed off the shielded FExx7E range. CRT screens employ an internal magnetic force to focus an electron beam; the aforementioned flat-screen types don't work like that, so no problems, unless you've got such a ludicrously powerful magnet nearby that it either screws up the internal ICs or possibly squeezes the plasma.

Depends how much you have to spend, and also what your amplifer is; the 206 isn't overly fond of most SS amps sans Eq, so this is something you might wish to consider before making any firm decisions. Better to do this now than later, right?
 
About my amp, it's Amp9 from 41Hz Audio, small company that sells kits. It's D class (also called T-class), DIY four channel Tripath TAA4100A based amp... Rated at 50W per channel.

BTW, I think there are still FE207E still available at few retailers... and I really like the fact that they are shielded. But if I don't have to worry that the 206 will mess with my plasma display (and the other consumer electronics...) , than I can go with that option also. Is the 206 noticeably better than 207?

I was thinking G Chang (or even Curvy Chang) for the 207 but you said that Sachiko (for the 206) is obsolescent... I guess I've missed something in my research.
What is by your opinion, the best sounding enclosure for the 207 and if you don't mind answering, please suggest one for the 206 too.
Or even better please suggest few of them so I have something more to research... :)
 
About my amp, it's Amp9 from 41Hz Audio, small company that sells kits. It's D class (also called T-class), DIY four channel Tripath TAA4100A based amp... Rated at 50W per channel.

BTW, I think there are still FE207E still available at few retailers... and I really like the fact that they are shielded. But if I don't have to worry that the 206 will mess with my plasma display (and the other consumer electronics...) , than I can go with that option also. Is the 206 noticeably better than 207?

I was thinking G Chang (or even Curvy Chang) for the 207 but you said that Sachiko (for the 206) is obsolescent... I guess I've missed something in my research.
What is by your opinion, the best sounding enclosure for the 207 and if you don't mind answering, please suggest one for the 206 too.
Or even better please suggest few of them so I have something more to research... :)


Vann, having heard the evolution of Scott's designs for Fostex and Mark Audio drivers over the past couple of years, "obsolete" is perhaps not entirely accurate - FE206E in Sachiko would certainly work, but "superceded" definitely.

FWIW my own personal experience with a limited sample of DIY chip and commercial digital amps is that the higher sensitivity FR Fostex drivers ( FE126/FE166, even FF165K) in any the continuum of "horn" designs in which they are generally employed can be very revealing of noise/distortion spectra or other sonic characteristics that might not display on any measurement, but can certainly be heard and result in long term listening fatigue. OTOH, I found the now discontinued "7" series to be generally more "forgiving" in this regard, without losing their ability to resolve the performance of more refined source / amplifier designs, be they solid or hollow state.
 
Tnx, crisb. All this coupled with the fact that 207 seem to be on slight discount (clearing supplies, prolly)... It seems that stars are aligning around 207 as a choice.

I chose to get involved with that Tripath based amp after reading how good it performed for the money and the fact that the kit is very cheep. With the (as little as) knowledge that I have now I would choose to build a tube amp. But things are as they are I intend to finish this though and use it for a given time.

Anyway, back to the 207... what enclosures to look into?
Those Changs look fine and some ppl here claim nice experience with them. From what I learned until now the horns are the way to go and the spawn family looked as not that hard to do... (I have a friend handy at woodworking).

Is there any consensus about best enclosure designs for this driver and about their strengths and weaknesses?
Any personal preference is also welcome... :)
 
frugal-phile™
Joined 2001
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As of Monday, Madisound has 41 FE207e. Get em while they last.

You'll likely want FE103En (or FE127 or FE103) for rears to maintain sonic signature.

Your amplifier is sufficiently powerful to open up a wider range of drivers, and as Chris is alluding, perhaps have greater synergy with your amps.

The Changs are not really horns, but BVRs (Big Vent Reflex)

dave
 
Yes I'm keeping an eye on 207 at Madisound for quite some time.... tnx for the low count warning.

Quick question, will Tang Band W4-930SF do anything close to a passing job for a rear speaker driver? Need to know this so I can order a pair together with the FE207E.
I'm not expecting wonders just I hope it won't be sonically too awfully different from the fronts...
 
frugal-phile™
Joined 2001
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I ordered the drivers, 2xFE207E and 2xTB W4-930SF. Man that overseas shipping is expensive... I ended dealing with a company specialized in cargo shipping by sea (I'm getting other stuff too, like pair of BOFU's, 15"subwoffer driver, amp, etc) In the end it was cheaper than any vendor from the old continent.

Depends on the ply. MDF is better than nothing at all, but isn't ideal for wide BW applications unless you can go to ludicrous thicknesses so is best employed for HF & midrange enclosures. Chipboard (particleboard) is somewhat more benign than MDF in terms of taming resonance, although unless you get a very high quality type it does crumble easily, so you need to be quite careful, especially when running the old hoover or Dyson around.
Well now I have time until parts arrive so I was thinking to start the cabinets but I can't find suitable ply around here even though I've been trying in many places.
I haven't given up on ply but I'm thinking to use particleboard (chipboard) for this first project...
I really liked the concept of horns but it seems to me that BVR is better suited for the FE207E. So, the most probable candidate is the straight G Chang. Since I'm getting a pair of Pioneer B30 also, the plan is to us them in Chang cabinets when I maybe decide on some other enclosure... maybe the Vulcan when Scott finish it. :)

About the particleboard and G Chang. Just looking at the design I see only 4 inside walls to straighten the box... will the particleboard be particularly bad choice for this enclosure? Will it be to hard to successfully stuff it and tame resonances?
 
Just as a reminder, Vulcan is designed specifically for the new FE206En. Nothing else. The defunct FE207E will not work in it.

Box material won't affect how difficult it is to stuff it, since the access to the enclosure is the same whatever you use, but taming panel resonances is another matter. You might want to put some cross-braces in, esp. if you're just using regular generic chipboard (particleboard).
 
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Shame I won't be able to use the 207's in Vulcan...

I haven't decided on chipboard vs ply yet. I prefer ply ofc, but it's damn hard to find quality ply here, not to even mention baltic birch variety. I've been to or phoned to most of the places that sell that kind of stuff... the thickest kind available is 1/2" or 12mm. I've heard that construction ply might be the answer (though somebody said that, it's not void of air bubbles/gaps) I'm really not looking forward to import ply, I'd rather go with particleboard in that case. (and suffer trying to tame resonances and I guess, not as good as sound)

In case of particleboard, should bigger thickness be used and is it better for the inner sides to be veneered/furnished/painted or bare?
You might want to put some cross-braces in, esp. if you're just using regular generic chipboard (particleboard).
About braces, should they be in the inner box, like it's shown bellow? (it won't interfere with the sound?)

5012032056_233ef801c4_b.jpg
 
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