Half Chang build

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~140Hour's burn in finished... :D

Dave & Scott, it's some amasing speaker's you have put together here... But for my setup, they really needed a lot of burn in time to achive theyre best!
I must say, that when i put them away, in my workshop last Sunday, i really didn't belive, that the Bass would increase when burn in ~100hour's... but it sure did, that's a fact....
When they reached ~75Hour's i had to turn volume down, otherwise it was too loud.. So something around soundpressure also happens to them when burning in.
well, i don't have them best ear's into hifi, but as time/experiance goe's they improve dramatically through. Them HalfChang Fostex FE207E really need burn in time in theese chassis i now know.

Jesper.
 
Hi
with reference to post #235, I found origionaly some modern music to be lacking in depth, some was due to driver break in, they do get better, but also some was due to compressed recordings. As the drivers settle down the sound fills out and even what are obviously compressed recordings start to sparkle.
Also an important fact that Scott pointed out to me is your ears take time to adjust to the different presentation, after weeks of not being able to listen to my speakers I found the presentation of some Tannoy monitors initialy more apealing (due to mayhem they were our only system for a while) and going back to the FE207eN's seemed a backward step, but as I got more chance for extened listening, the Fostex and the cabinet again worked thier magic on my listening pleasue, ie no listening fatigue and becoming involved with the music. I have found with Fostexs and a Valve set up that letting them settle down for a few teracks before you realy listen helps, I now give everything chance to warm up before I sit down and listen as the initial tracks always sound thin, so a warm up for both amps and drivers helps (IMO).
 
Has anyone referenced the half changs with full curvey changs? using the same driver? ie the fe207e...

I am going to built the HalfChangs as my next project.

Does anyone know where I can get descent price for 2 x fe207e's in australia?

I have 3 options:

aussie company sells the 207e's for $150ea + maybe $20 postage for 2, total $320.00au for 2.

usa company $89.98 ea + unkown postage (maybe $50) total $230us for 2

worth getting in from usa, would they normally be packaged well enough for international shipping?

specifically 2 I found on the web: oregondv & madisound.

cheers, stevo.
 
I had a most revealing experience this weekend when I delivered the (finally) completed Half Chang speakers (w/ Fostex FE206e drivers) to our daughter and son-in-law, and thought I’d share it here.

While tuning the stuffing and baffle step circuit, I ran the HCs on two of my systems: one a Yamaha CR-1000 (vintage 1976) with Dennon DCP, the other a Sansui 4000 (vintage 1974) with a Toshiba DVD/CDP. The HCs sound truly spectacular on both systems. I wouldn’t be ashamed to match them up against anything in the $2,500 to $3,000 range.

I had loaned the kids a pair of BB Insignias to tide them over until the HCs were done, and given them a modded Radio Shack Accurian amp to drive them. The Accurian is maybe a little rough in the highs, but at $15, it is wildly over-achieving.

So I connect the HCs to the Accurian, which is connected to their Sony TV and through that to a Sony PS2 (to play DVDs and CDs as well as games.) I put my test CD in the PS2 and fire it up. Loud enough to hear what’s going on, but no where near clipping. Things are sounding OK, but not great. Then I get to my test tract for sibilance: Lara Fabian singing Urgent Desire. And it’s not just bad, it’s unlistenable! What happened? Were the speakers damaged in transit? Quick, pull the receiver I gave them two years ago (a RS AVR we picked up for free from the estate of my wife’s late uncle) from their living room and substitute that for the Accurian. Dramatic improvement! Not as good as my systems, but definitely listenable.

I have heard differences between amps before, but NEVER anything like this. With the HCs, the Accurian produced this horrid, distorted sound; the RS AVR produced a mildly sibilant sound; and my systems produced only a trace of sibilance.

This makes me think that many 2 and 3 way speakers unintentionally alleviate such problems by losing information in their cross-overs. Others may use a notch filter to intentionally block such signals. With single fullrange drivers, large panel drivers, and other highly resolving speakers, one must be careful to preserve the original signal throughout the whole chain! Now I have to think about getting the kids another amp.

Cheers, Jim
 
I doubt it, to be honest. The Pioneer will still be covering the telephone band, and for all it's undoubted merits (astonishing value if you live in the US, almost bomb-proof, sins of omission rather than addition) it does not have the reputation of matching Fostex units WRT detail.

I still keep meaning to import a pair though -it's cheaper to get them from the US (despite international postage, Customs charges, VAT & import duty, plus the UK end of the postage's own handling fee, which they slap on everything) than it is to buy them in Europe. I've always had a liking for cheap products that offer great sound for the money & the B20 is a classic.
 
Jim,

I had a very similar experience. i built a pair of HCs for my son and daughter-in-law. When I delivered them I took along a Marantz 1060 70s vintage integrated amp. The combination sounded wonderful and a joy to listen to. I left the amp with them for them to use. My son has since told be that he switched out the 1060 for a remote controlled HT receiver because he didn't like having to get up all the time to change the volume; even though, according to my son, the HT receiver doesn't hold a candle to the 1060.

What can you do? You can lead them to water but you can't make them drink.

Bill
 
twitchie said:
I would suspect the TV (your pre-amp in this case). I've done that before with a pair of rotel power amps and it sounded awful and compressed for music


If that were the case, then the other amp should have had the same issue. And it wasn't compressed, it was sibilant hash (truly distorted,) while the other mids & highs were merely a bit harsher than might be hoped.

Cheers, Jim
 
Not sure if this was covered in here or in the general frugal threads, but will there be much difference between using a straight 1 piece wood for deflector rather than the stepped strips... (Other than not having to backfill the area behind the ramp deflector.

will it sound better or 'fuller' or woulf the 'ramp' sound 'thiner' or something...

I'm just working out the cut plans to send to the cabinet maker thats all.
 
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stevodude said:
Not sure if this was covered in here or in the general frugal threads, but will there be much difference between using a straight 1 piece wood for deflector rather than the stepped strips... (Other than not having to backfill the area behind the ramp deflector.

will it sound better or 'fuller' or woulf the 'ramp' sound 'thiner' or something...

I'm just working out the cut plans to send to the cabinet maker thats all.

Ignoring any issues of mass loading or lack of panel resonance (the steps deal with these inherently) there should be no sonic differences.

dave
 
so why would I waste wood on steps rather than a ramp and backfill the space?

so I made a cut list using L&R side full length, top/bottom inside and back inside full length. also a cut list of stepped deflector.

2 sets of below in 18mm mdf

1 x 1185 x 240
2 x 1185 x 328
1 x 768 x 240
2 x 310 x 240
1 x 273 x 240
1 x 82 x 240

all cuts below are (x,y) (X,240mm)
301
283
265
247
229
211
193
175
157
139
121
103
85
67
49
31
13
 
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