Creative Sound FR125

londondan

Member
2010-08-05 3:20 pm
Hi All,

wanted to start this thread to see if any one has had any build experience with the CCS FR125 full range drive unit. (you can download the data sheet from madaboutsound.com).

I use a set of KT88 monoblocks, and I am now convinced that passive cross overs, degrade sound, and dissipate power overwise used in moving speaker mass.

Has any one used these in a transmission line or open baffle arrangement in particular?


PEACE
London Dan
 
I use four of the WR 125's in this configuration along with a helper tweeter. They are quite good. The center woofer is optional with those boxes.
 

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Digeridoo

Member
2004-10-26 8:44 pm
CSS FR125: I like it; needs careful design...

Hi -- I've used the FR125 in a number of applications. Upshot is that it's one of the driver's I'd recommend to someone looking to explore full-range. When they're in the right cab and set-up right, the full-range magic is definately there. Enough bass to not neccessarily require a sub, great midrange, and to many ears doesn't require a tweeter. Downside in my experience is that it's difficult to extract the full bass potential of the driver -- without sufficient damping it can hit it's excursion limits in ways that aren't pretty. Because of the bass potential of the driver it's tempting to push it to the limits... but in my experience I've found that aiming for best driver "control" yields the best results. In short, go for controlled, as opposed to lowest, bass. I've had best results with some sort of resistive loading, such as a foam-stuffed vent. Dave Dlugos et al/Planet 10's onken designs are good; here's my take on one of Planet 10's designs using a resistive vent; in next generation I would put the resistive vent in the base of the cab, which would facilitate optimizing the vent damping/tuning:
Best, John
 

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Cal, what frequency have you tuned your boxs to?
I don't really know, they are on planet10's site if you want to have a look at the plans and plots. They are called the Calhoun.

Hey Cal, how far back from those things do you sit?
I didn't seem to find that I had to be back from them but as always you have to place the speakers in the right part of the room and then sit in the right part to achieve the bass if there was no helper woofer. I am wondering if you were sitting in just the right spot to catch all the bass reflections gathered at one spot. That was kind of spooky when you are hearing that much bass from such small drivers.
 
Downside in my experience is that it's difficult to extract the full bass potential of the driver -- without sufficient damping it can hit it's excursion limits in ways that aren't pretty.

Yeah, I bounced mine off the back plate more than a few times on certain passages even at modest apartment levels in RS 40-1354 MLTLs, so while they didn't seem damaged, into the closet they went.

Another thread got me thinking about a tall skinny cab to maybe provide enough acoustic loading, so 'stretched' a sim of the MLTL to 58" and except for an unavoidable deep notch in the lower mids it looks viable. Only one way to know for sure though.

GM
 
FR125 as midrange

FR125: not without a tweeter and SDX7 as a midbass thank you very much....and a sub. FR125 is now relegated to midrange (running fullrange all it does is midrange as far as I am concerned) in a 4.5 litre aperiodic box and finally am NOT disappointed with these drivers after 5 years or so. But they are the sweetest most open mids ever.
 

londondan

Member
2010-08-05 3:20 pm
Dear All, thanks yet again to your replies.

Gringo Audio, you may have mis read the beginning of my thread.
I am looking to produce a design, that is free of cross-overs, minimising distortion and raising efficiency, such that the cross over does not reduce the out-of box-sensitivity. So the addition of a tweeter does not meet my objective.:mad:

I am intending to use my REL Quake Subwoofer (google REL acoustics) picking up the duty from around 110hz. DOES ANY ONE HAVE ANY THOUGHTS IN THIS?:confused:

Digereedo, amazing litte cabs you have produced there.:cool: very impressed.

I am plugging away now on sketch up. Hopefully I will get a post up for my design by the weekend.

I am considering an quarter wave tower.

All the best Guys

Dan
 
OK, a wide BW sub seems to make this a 'no-brainer' then. Increase the driver's effective Qts due to the amp's high output impedance, then design as flat a sealed alignment as practical since a SET amp will have enough output impedance to raise it to at least 0.7, then choose the XO point that yields the flattest in-room response.

Note that if you do choose sealed, a tower design will have 1/2 WL action with a broadband notch down around tuning if end loaded, so driver position works best around 2/5 (0.4) internal line length. For example, a 40" internal driver height will have a ~(40"/0.6) = ~66.67" line length.

GM