CSS FR125S ... production units playing now...

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Westend -

I did use the Northcreek sizing guide, so just under 2L in the aperiodic section (and stuffed with polyfill), and the breathing area is VAS (~5.5L). I did not use a ScanVent, I just used a piece or 3/4" plywood with a 2.5 or 3" hole in it, a bit of fiberglass insulation (it's been a while but I think about 2.5 - 3 inches uncompressed), and a thinner (1/8") piece of wood with a matching hole to compress the fiberglass screwed into the thicker plywood on the back. The back of the thicker plywood was also rounded over just in case. This picture should help clear things up...

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


Concerning a planar or ribbon... I personally think the FR125 needs the help of a supertweeter. They sound good on axis but tend to lose a lot of their higher frequency once you get off axis and I listen off-axis pretty often. I used a planar with the WR125 to very good results, but I brought it in around 3.5kHz and rolled off the WR so it was really more of a 2 way than a fullrange with supertweeter. With the FR, I am running the FR full range and am employing the help of a supertweeter brought in around 10kHz to help with dispersion and give the speaker a bit of sparkle. Here's a pic of the WR with the HiVi RT1L planar...

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


With that said - I really don't see the point in spending the money for a ribbon or planar only to use it in a range where my hearing is not top notch. A decent dome with a smooth top end and extension out to 25kHz or so is fine with me. The one I'm playing with right now is the surface mount Dayton Neo (PE #275-030). I like it because it has almost no flange, a fairly smooth top end, and heck, they only cost $4.60 a piece. The small flange allows me to mount it as close as possible to the FR to prevent massive combing effects. And personally, I think it really sounds nice in this range - cymbals sound great. This tweeter definately bellies it's low price. I'm not quite done with this one yet so I don't have any pictures but it's using the MAPD enclosure pictured in the top pic.

Good luck.
 
Interesting post! I'm currently building my second set of FR125S fullrange speakers. I've theorized about using a tweeter crossed over above 10kHz for two reasons: 1. dispersion, 2. better high end response. However, the beauty of a fullrange speaker lies in the phase coherency. Personally, I don't think the FR125S benefits of a tweeter, the tradeoffs outweigh them.
However, i'm considering a fullranger combind with a bass driver crossed over between 200- 400 Hz using a first-order crossover. I'm surprised that this concept doesn't get attention on these forums because I think it could be truly awesome: better power handling, less distortion in bass, still great phase coherency and of course lower bass...Has anyone considered or built such a speaker?
 
It looks like what you're suggesting is a three way speaker using the FR 125, is that right? I really don't know why it wouldn't work, although the use of a WR 125 would give you probably the same results or at least approximately. You probably won't see a whole bunch on this forum as it tends toward fullrange or widerange speakers.
But rather than admonishing you for bringing up a forbidden topic on this forum, I'll give you a URL that should give you some ideas as to the feasibilty of this approach.

http://www.diycable.com/main/product_info.php?cPath=24_92&products_id=571

Everyone that's heard these has been quite taken by them and at the asking price they're quite a bargin. Good company to deal with as well.

In Canada, Al Wooly of Raw Acoustic has some well regarded speaker designs that utize these drivers, but I don't know what's available in kit form. Al's also a good guy to deal with.

Disclaimer: Both of these individuals I regard as friends, but I have no financial ties to their respective companies. If one or the other's product wasn't first class I wouldn't bother mentioning it
Hope this helps, good luck.

Best Regards,
TerryO
 
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madscience said:
However, i'm considering a fullranger combind with a bass driver crossed over between 200- 400 Hz using a first-order crossover.

A FAST system (i still don't know what the acronym stands for). A very valid concept. A bit harder to find examples of, but there are quite a few... the Basszilla being one example. Illusus has a very nice system with a JBL woof & the FE166SER. I've a number of these in the queue... closest is an unobtainum TB 3" plus a pair of push-push coral 8".

These systems would ideally bi-amped, but should also respond to series or parallel 1st order XOs.

dave
 
Personally, I don't think the FR125S benefits of a tweeter, the tradeoffs outweigh them.
I think it depends a lot on the situation..or type of room you listen in. In nearfield listening (small computer room)..a tweeter is IMO useless. In a big room (or at least in my living room...which opens into the dining room...and kitchen...and upwards with a spiralling staircase)somehow the treble is sucked right out of the FR..(or so it sounds).....and a tweeter does the speaker a favour in that situation.
 
TerryO: Actually I'm considering a 2-way system. This requires the use of a small fullranger - a 3" driver looks like a good compromise to me. The speaker kit you mentioned must be a killer system, but still way out of my financial possibilities (I'm a university student).

By the way, linearity in frequency response has a high priority on my list, so I'm looking for a fullranger that is small, linear, but with a low cutoff point (around 200 Hz or lower). Any ideas? I'm currently studying the TB 3", Omnesaudio BB 3.01 (which looks excellent on paper) and other candidates. The HiVi units seem to be of high quality but there doesn't seem to be a distributor in my vicinity (which is Europe). There's seems to be little info on the BB 3.01 of which I'd really like to know more. Anyone?

I'm sorry for being off-topic but let's look at it like we're comparing the FR125S high end response to other drivers.
 
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Joined 2001
Paid Member
madscience said:
By the way, linearity in frequency response has a high priority on my list, so I'm looking for a fullranger that is small, linear, but with a low cutoff point (around 200 Hz or lower). Any ideas? I'm currently studying the TB 3", Omnesaudio BB 3.01 (which looks excellent on paper) and other candidates. The HiVi units seem to be of high quality but there doesn't seem to be a distributor in my vicinity (which is Europe). There's seems to be little info on the BB 3.01 of which I'd really like to know more. Anyone?

BB3.01?

My fave 3" so far is the Aura NS3. In a small sealed box it can get close to 100 Hz. Not very efficient thou.

dave
 
Chris,
Thanks for posting back with your results. I'm going to build a pair of the aperiodic boxes and see what they bring. If tweeters are needed I'll visit that solution after I've had a bit of listening time. My experiments with the FR125 in OB showed enough top end to keep me happy but we'll see. I plan to use the speakers for HT so the added sizzle on top might not be needed.
For the other poster looking for a 3"; as recommended by Dave, the Aurasounds are on sale here at Madisound:http://www.madisound.com/cgi-bin/index.cgi?cart_id=7566365.23176&pid=1757. You can contact them as to shipping prices. I read someone frpm Sweden was purchasing from Madisound because the price of all combined fees and taxes were cheaper than purchasing from a Euro distributor, YMMV.
 
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westend said:
For the other poster looking for a 3"; as recommended by Dave, the Aurasounds are on sale here at Madisound:http://www.madisound.com/cgi-bin/index.cgi?cart_id=7566365.23176&pid=1757. You can contact them as to shipping prices. I read someone frpm Sweden was purchasing from Madisound because the price of all combined fees and taxes were cheaper than purchasing from a Euro distributor, YMMV.

That one would probably work if you only need to reach 200 Hz and is more efficient... the one i was referring to was this one http://www.madisound.com/cgi-bin/index.cgi?cart_id=7566365.23176&pid=100 -- also available with black cone.

NS3-193-8A.jpg


dave
 
Sorry about any confusion regarding the Aurasound drivers. I thought to apply Madscience's needs (price, 3", >200hz) to the products. I realize the "extended range" Aura is the better driver. It does cost a little more, however.
I should have Chris's Northcreek MAPD design for the FR125's up and running tomorrow. Many thanks to Chris, Dave, and all here for your information and ideas on this driver. I'll try to post some pics and a cutlist up here, as well. Some folks might like this box because I've used the CSS baffles and I think it will deal nicely with the low end.
Northcreek and others referencing the aperiodic enclosures suggest to stuff the compression chamber full. Is that a must? Is it for back wave reflections or is it for dampening frequencies?
 
I have the FR125 in the Northcreek based MAPD up and running. Again, many thanks to Chris, Planet 10, and others for sharing their knowledge and experience with enclosures and this driver.
Cabinet exterior dimensions are H=11" W=6.5" D=12"Compression chamber volume=.066^' Larger chamber is .199^'. Total volume=.265^'.Chamber through hole is 2"Dia.These dimensions allow the use of the CNC baffles that are available. I'm using my laptop and the Sonic Impact original T amp at present. Tomorrow I'll give them a run with larger gear and can post back then. First impressions: The MAPD deals with the bass in an adequate manner. The bass is only limited by the driver's rolloff. It's tight and not boomy at all. The imaging with these boxes is great, especially nearfield. The mids and highs are clear and detailed. For my listening habits, a tweeter wouldn't be necesary. The bass is not up to a full two channel set,IMO, but is more than adequate for nearfield or HT use. A subwoofer would get it all together, especially crossed high to 100 +hz. I had the compression chamber stuffed with dacron but removed it as I don't think it afforded any effect. I used dacron as the aperiodic vent, as well. One layer of 1/2" behind the hole and hole stuffed with 1".
Overall, a great driver with an enclosure that mates well.
I tried to attach a pic but my resolutions are too big. I'll have my little photo editor tackle that in the AM.:angel:
 
sorry for being such a newbie, but can someone tell me the advantage in these kind of drivers. Currently i'm a dyanudio MC15 owner and i like my active speakers ... cutting out the middle man as such, but if i were interested in having a go with building my own speakers, what's the advantage/disadvantage in buying such drivers?

Why choose these over something i could buy from Maplins for example?

Also I see these kind of drivers with reference to tube amps, why tube amps? Again sorry for being a total newbie, i'm a headphone person myself, but i do like my speakers.
 
If you want 20Hz, you're in the wrong league. Wide-band drivers do many things well, but sub-bass is not one of them. That's not what they're designed for, and why there are such devices as dedicated sub-bass drivers, 18in woofers etc. Technically, you can get it with horn loading, but they'll be enormous, and dynamic bandwidth will be poor.

Where the advantage lies is in maintaining a point source & no crossover with all its attendent issues slap-bang in the middle of our critical hearing bandwidth (nee midband -200Hz - 4KHz). Good way forward is big bass drivers with a wide-band unit, making a classic 2-way with the crossover frequency much lower than most modern multiways, affecting less of the midrange.
 
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