FR125S for surround sound.

[AAK]

Hi all,

I'd like to use a single FR125S in 2.5ltr sealed enclosure to make up my front, and rear speakers, and two FR125S in a 5ltr sealed enclosure for the center channel. I calculated and F3 of about 100Hz, Qtc less than one, and figured with good subwoofer could make out to be a nice system. Hopefully better than a BOSE. Just wanted to here from those that are experienced with the FR125S whether it's worth the effort?

Thanks,

Al

[badman]

Hopefully better than bose?! HOPEFULLY?!!!

Kidding aside, any halfway competent design with the FR125 will have better sound than bose- an octave more response in either direction, much higher output levels and lower distortion, the only advantage bose has is dispersion due to the tiny tiny drivers.

Yes, go for it. Think about your various enclosure options, are you doing the higher-Q alignments for the "response knee" as a sort of baffle step compensator?

Also, do you have a 5ch power amp that can put out a little juice? The FR125 is pretty insensitive.

But by all means, take the trouble. I use the FR125 at work in little bowling ball sized spherical enclosures, where it sounds fantabulous.

[AAK]

Hi badman,

Thanks, that's encouraging. My comment on BOSE should of had several exclamation points. I just don't know what got into me.

My multichannel amp can handle 100watts into 8 ohms with ease. BTW, how much power can the FR125S safely handle? Is the SPL according to specs. of 86db @1w/1m?

Thanks,

Al

[tinitus]

Hi,

I have once thought the same, that FR125 could be ideal as center and backspeaker - but I have realized they are VERY low efficient and limited in SPL - I think some has measured it to be close to 80db
But it does sound nice though

[Bas Horneman]

SPL - I think some has measured it to be close to 80db

It's pretty low indeed. So it comes down to the size of one's room. In a smallish/medium size it is fine. Might not be sufficient in a big room especially if you are an American . I'm told Americans like their sound volume big or so the UK hifi mags have let me to believe... (A lot of us Europeans have to take the neighbours into consideration)

Also in big rooms a super tweeter might be needed because the higher frequencies taper off when listening off axis.

That said I have an above average room (for the Netherlands that is) and I'm planning a 5.1 with the fr's as well.

[badman]

If the unit can do 100WRMS cleanly, you should be able to drive the FRs well beyond Xmax, which means, it's plenty of amp. They ARE 4.5"s after all

So long as your SPL requirements are reasonable (IE, not 110dB), you should get very nice sound.

[Timn8ter]

Similar question posed in another thread.
To do loud with a single FR125S you need to control the excursion. A good start is putting them into a sealed enclosure. In a home theater setup with an A/V receiver or pre-pro it's easy. The louder you want to go the higher the XO frequency. Crossed at 100Hz they will play quite loud.

[Bas Horneman]

To do loud with a single FR125S you need to control the excursion. A good start is putting them into a sealed enclosure.

Sounds better to me as well...at least compared to what a fellow board member had here today. I have a deep sealed box speaker with the FR125..and that sounds waay tighter than his bass reflex version.

[Jim Griffin]

Playing around with my Bass Pro 6 program shows that the FR125S in a sealed box isn't too bad in a 2.5 liters volume. With minimal stuffing the F3 point is 103 Hz with a Qtc of 0.856. In this small sealed box you have inherent protection of the driver. At 70 watts input the rated Xmax of 6 mm is reached and this level is maintained from 100 Hz down to DC. The 1 watt SPL is 86 dB and with 70 watts input the SPL output is 105.5 dB or so. That performance is very respectable. Now if you add baffle step comp, you'll primarily impact the upper frequency end of the band. So this approach might be acceptable to you if a 3 dB lower sensitivity with a 4 ohms resistor in an RL BSC circuit.

Jim

[Timn8ter]

You're on the right track AAK!