FR125s in open baffles

Fuling · 20th July 2007, 03:24 PM

Hello,

No matter how many times I´ve failed in building open baffle speakers that I can live with I still can´t get them out of my mind.
It seems to be true that once you have tasted OB you´ll never go back to regular boxes...

My latest attempt was a hybrid system with FE167E in 120x66cm oak baffles and SS8545 woofers in closed cabs integrated in the baffles. Sounded fairly good, but the big difference in driver efficiency called for biamping which took all the fun out of the hobby (Building amps is what I like best and I want my speakers to be compatible with every amp I build, not just my lousy four channel tube amp).
FE167E isn´t the best choice for open baffles either.

I had a little break from hifi and DIY a while ago and when I got back it wasn´t as fun as it used to be and I realised that the speakers was the problem, I couldn´t just change things in the signal chain anymore since I was stuck with my active crossover/preamp and my 4 channel amp.
The solution was to put the Fostex drivers back into their 24L BR boxes. Now I could experiment as much as I wanted with the rest of the system, but suddenly I began to miss the OB sound...

For one reason or another I ordered a pair of CSS FR125s a couple of days ago, the idea is to build another hybrid system with them fullrangers in open baffles and a pair of Peerless 5,25" drivers in closed cabs for bass support. The sensitivity matches much better between these two drivers so hopefully I can get away with first order passive XO in the 200-300Hz range.

BHTX · 20th July 2007, 03:36 PM

I've heard that the FR125 and WR125 make great OB's, which didn't surprise me the least bit, with their highish qts. Might need a simple notch filter tho, and beaming might be an issue. But, if you're used to full range drivers, maybe it won't bug you like it would me. But yeah, good choice with the FR125's! And I think they should work pretty well with the SS8545's too. Your xo sounds about right. Despite what others have said about the FR125's performance in the lower octaves, tests will show that it'll perform it's best roughly around 400Hz and up. I can't seem to find my reference atm for that tho. Maybe I'll stumble across it later. Goodluck with your project.

BHTX · 20th July 2007, 03:56 PM

Just came across this one. Just another recommendation from an FR125 OB'er..
http://fullrangedriver.com/forum/viewtopic.php?id=239

And this, lol..
http://www.youtube.com/watch?v=CvmyHG5mmQA

Fuling · 20th July 2007, 04:22 PM

I guess the XO freq. will be determined by what caps and inductors I can find i my junkbox, at least initially

The baffles in the first link looks pretty much like my previous ones, I used oak panels and piano hinges. I still have them around so what I will do is to move the wings over to new middle pieces. The wings are 160 and 200mm wide, and 300mm panels are also available.
I think I´ll try with just the FR125´s alone before I cut holes for the bass drivers.

BHTX · 20th July 2007, 04:30 PM

Yeah, I absolutely LOVE the over all look of the CSS FR drivers, with their copper phase plugs, against real wood panels/veneers of that color. If and when I ever give in and buy a pair to play around with (which I probably will), that's definitely the look I'll go with. And yeah, I'd wait on bass drivers too. Only possible downside is that you might end up with a little procrastination with those Peerless woofers?

Fuling · 20th July 2007, 05:18 PM

Quote:

might end up with a little procrastination with those Peerless woofers?

I secretly hope so

I had some regrets about cutting holes for the Scanspeak woofers in my latest baffles, so I´ll be careful not to do the same mistake again. Separate "sub"woofer enclosures would be an option, but the distance between the drivers versus the high XO frequency might be a problem.
The best way to know will is of course to find it out myself, so no woofers in the baffles to begin with!

planet10 · 20th July 2007, 07:04 PM

FR125S should work really well if XOed above at least 150 Hz... we tried them in OB 2 diyFests ago and they run out of steam far too early in the bottom.

And keep in mind that it is pretty simple to dramatically improve the FRs performance -- so much so that i don't think i'll bother selling them without that tweak.

dave

Fuling · 20th July 2007, 08:31 PM

Well, I´m getting more and more excited about these drivers without having heard them yet!
I´ve found a fairly big sheet of plywood that will be cut in two and used as test baffles the same minute the drivers arrive, oak is too expensive to use in prototypes

Quote:

it is pretty simple to dramatically improve the FRs performance

May I ask how?

planet10 · 20th July 2007, 09:43 PM

Quote:

Originally posted by Fuling
May I ask how?

2 vanishingly thin coats of C37. At some point (i have to find bottles etc) i will probably sell little kits because the minimum amount of C37 you can buy will do many, many drivers (and costs as much as a pair)

Puzzlecoat works a bit less effectively (and if you aren't really careful can end up having you glue the voice coial to the phase plug)

dave

Fuling · 20th July 2007, 10:04 PM

Sounds interesting! I´ve read alot about coating drivers but never tried it myself.

20th July 2007, 03:24 PM	#1
Fuling diyAudio Member Join Date: Aug 2001 Location: Sweden (Mora)	FR125s in open baffles Hello, No matter how many times I´ve failed in building open baffle speakers that I can live with I still can´t get them out of my mind. It seems to be true that once you have tasted OB you´ll never go back to regular boxes... My latest attempt was a hybrid system with FE167E in 120x66cm oak baffles and SS8545 woofers in closed cabs integrated in the baffles. Sounded fairly good, but the big difference in driver efficiency called for biamping which took all the fun out of the hobby (Building amps is what I like best and I want my speakers to be compatible with every amp I build, not just my lousy four channel tube amp). FE167E isn´t the best choice for open baffles either. I had a little break from hifi and DIY a while ago and when I got back it wasn´t as fun as it used to be and I realised that the speakers was the problem, I couldn´t just change things in the signal chain anymore since I was stuck with my active crossover/preamp and my 4 channel amp. The solution was to put the Fostex drivers back into their 24L BR boxes. Now I could experiment as much as I wanted with the rest of the system, but suddenly I began to miss the OB sound... For one reason or another I ordered a pair of CSS FR125s a couple of days ago, the idea is to build another hybrid system with them fullrangers in open baffles and a pair of Peerless 5,25" drivers in closed cabs for bass support. The sensitivity matches much better between these two drivers so hopefully I can get away with first order passive XO in the 200-300Hz range.

20th July 2007, 07:04 PM	#7
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	FR125S should work really well if XOed above at least 150 Hz... we tried them in OB 2 diyFests ago and they run out of steam far too early in the bottom. And keep in mind that it is pretty simple to dramatically improve the FRs performance -- so much so that i don't think i'll bother selling them without that tweak. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

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20th July 2007, 03:36 PM	#2
BHTX diyAudio Member Join Date: Feb 2006	I've heard that the FR125 and WR125 make great OB's, which didn't surprise me the least bit, with their highish qts. Might need a simple notch filter tho, and beaming might be an issue. But, if you're used to full range drivers, maybe it won't bug you like it would me. But yeah, good choice with the FR125's! And I think they should work pretty well with the SS8545's too. Your xo sounds about right. Despite what others have said about the FR125's performance in the lower octaves, tests will show that it'll perform it's best roughly around 400Hz and up. I can't seem to find my reference atm for that tho. Maybe I'll stumble across it later. Goodluck with your project.

20th July 2007, 03:56 PM	#3
BHTX diyAudio Member Join Date: Feb 2006	Just came across this one. Just another recommendation from an FR125 OB'er.. http://fullrangedriver.com/forum/viewtopic.php?id=239 And this, lol.. http://www.youtube.com/watch?v=CvmyHG5mmQA

20th July 2007, 04:22 PM	#4
Fuling diyAudio Member Join Date: Aug 2001 Location: Sweden (Mora)	I guess the XO freq. will be determined by what caps and inductors I can find i my junkbox, at least initially The baffles in the first link looks pretty much like my previous ones, I used oak panels and piano hinges. I still have them around so what I will do is to move the wings over to new middle pieces. The wings are 160 and 200mm wide, and 300mm panels are also available. I think I´ll try with just the FR125´s alone before I cut holes for the bass drivers.

20th July 2007, 04:30 PM	#5
BHTX diyAudio Member Join Date: Feb 2006	Yeah, I absolutely LOVE the over all look of the CSS FR drivers, with their copper phase plugs, against real wood panels/veneers of that color. If and when I ever give in and buy a pair to play around with (which I probably will), that's definitely the look I'll go with. And yeah, I'd wait on bass drivers too. Only possible downside is that you might end up with a little procrastination with those Peerless woofers?

20th July 2007, 10:04 PM	#10
Fuling diyAudio Member Join Date: Aug 2001 Location: Sweden (Mora)	Sounds interesting! I´ve read alot about coating drivers but never tried it myself.

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