CSS FR125S Cabinet

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Sims of 7, 13 & 28 liter sealed FR125S enclosures all look pretty much the same but the 7 & 9 liter BR look quite different. The 7L has that pronounced 100Hz hump while the 9L is flatter. One thing I noticed is the difference between lightly stuffed BR vs heavily stuffed. The heavily stuffed BR box flattens that lower impedance hump more like the AV boxes do.
 
I've almost finished building my 13 litre box. I plan on leaving it sealed first to see how it sounds. Preliminary (non sealed - small gaps due to my poor woodworking skills :bawling:) tests sound very good. Just need to seal and paint the box then I'll get some pics up.

One thing that amazes me about these speakers is there excursion. They move so much with their light little cones, I find it quite interesting to watch.
 
For nearfield imaging I thought the FR125 was great. Yes, they have excursion. They also can't take a whole lot under 60hz or so. Since they do play so low and had a pretty full sound I was always trying to turn them up to fill a big room and that wasn't successful. I use them now in an aperiodic box for HT surrounds and they excel at that.
 
As promised I have some pics of my FR125S' in a sealed 13 liter box. I still havent got around to sealing or painting these and for the time being theyre being run without any foam lining the insides or braces.

I also added a pic of my 1st Yr EE Project amplifier and my 12-0-12 power supply I made from a battery charger and an old valve heater transformer. The bridge rectifiers and the capacitors (about 5500uf per rail) I stole from some old CRT's. I know its not exactly audiophile, but with my current source (AC97 soundcard) and poor amp I really couldnt hear the difference.

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
Yeah the speakers are excellent! after reading all of the sealed vs ported box threads I really was expecting lacky bass in the sealed setup. I always thought I was quite a bass person, but these sound great to me. They seem to do classical music VERY well too, which is good for me. The amplifier sounds fine to me, but I designed it so I know it can be improved 😉

My next step forward will be to finish off the speakers and then probably build a chipamp, LM1875 perhaps?
 
had a play with the drivers in an old pair of speakers that they just happen to fit, there roughly around 4L (were ported but i stuffed them with a sock) and even then they sound good with only 6 hours of playing! sound very clear and disapear especially with vocals.

listend to a song by kris kristofferson, (beat the devil) and without a BSC he sounded big and very clear!
 
Bonce said:
Yeah the speakers are excellent! after reading all of the sealed vs ported box threads I really was expecting lacky bass in the sealed setup. I always thought I was quite a bass person, but these sound great to me. They seem to do classical music VERY well too, which is good for me. The amplifier sounds fine to me, but I designed it so I know it can be improved 😉

My next step forward will be to finish off the speakers and then probably build a chipamp, LM1875 perhaps?
I used the SI T-amp with the FR125 for ahile. Worked real good for me. How many watts does the LM1875 put out?
 
Im not exactly sure but I've been thinking and I'll probably just go for the 3886 in case I ever need to drive different speakers. I'll alos use my current amplifier as a preamp (It has a bit of gain, tone controls and level meter) and simply feed the output of that straight into the chip.

Im hoping that the +-18v of my current PSU will be enough to drive the lm3886 up to decent levels.

Those speakers are looking good by the way. I think its maybe time I invested in some better woodworking equipment 😉
 
Bonce said:
Im not exactly sure but I've been thinking and I'll probably just go for the 3886 in case I ever need to drive different speakers. I'll alos use my current amplifier as a preamp (It has a bit of gain, tone controls and level meter) and simply feed the output of that straight into the chip.

Im hoping that the +-18v of my current PSU will be enough to drive the lm3886 up to decent levels.

Those speakers are looking good by the way. I think its maybe time I invested in some better woodworking equipment 😉
You could lamiate the outside of the box with plywood or other. I was really liking the T-amp. Must be the battery power and the accuracy combined, I'm thinking. I've been looking at the other chip amps, particulary, the Charlize: http://diyparadise.com/charlize.html. I'll be using it for a pair of single driver FE126 horns so a lot of watts isn't necesary.
I drive the FR125 with the Panasonic XR-55 class "D" amp and that isn't a bad mate, either.
 
Sorry about the late reply but I decided I would get my chip amp finished before posting pics of it all:

http://www.freemyimage.com/ims/pic.php?u=7CRGFR&i=618

http://www.freemyimage.com/ims/pic.php?u=7CRGFR&i=619

The Amp is very badly made (rushed in about an hour last night) with a standard bridge rectifier, an old pentium 1 heatsink and my two old transformer wired to give +-18v after the rectifier. The sound is VERY good. This amp is a lot more punchy than my old one, and surprisingly there is less hum in that I can only hear it with my head pressed against the cone.

It can also go surprisingly loud with only +-18v, and my Fr125S' bottom out with the pot only aboyt half way. It also remains absolutely cool to the touch, even with my speakers going all of the way.

All in all, a very good project, I think its now time to tidy it up a bit 😉
 
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