FR125 How connect it to get more SPL

[samsagaz]

Hi i purchased 5 FR125 drivers some years ago for HT. Now i want a little more power and more SPL so was thinking abt make some new cabinet with 2 drivers on each one and use a bigger amp. is that possible ? how recommend me to connect the fr125s? wich enclosure?

Thanks

 

[chrisb]

Of course - there are a number of bi-pole designs to be found below, of which I've built several.
Frugal-phile | Box Library / CSS

One caution to note is that under certain circumstances, the FR and WR125s could exhibit some unfortunate sonic behaviour - we at first attributed it to low damping factor SET amps with which we were flirting at the time, but also noticed the same with chip amps, and narrowed it down to that when driven very hard in under-damped vented enclosures the suspension's compliance didn't quite control the voice coil former from hitting the back plate on the return stroke.

I can never remember this being a problem in any of the sealed or aperiodic enclosures, such as the original mini-onken, or the little 4 litre wedge

 

[planet10]

Consider adding helper woofers.

dave

 

[samsagaz]

Thanks. Will check the designs! Some todo recommendme?

[/LIST]7]Of course - there are a number of bi-pole designs to be found below, of which I've built several.
http://frugal-phile.com/boxes-CSS.html

One caution to note is that under certain circumstances, the FR and WR125s could exhibit some unfortunate sonic behaviour. We at first attributed it to low damping factor SET amps with which we were flirting at the time, but also noticed the same with chip amps, and narrowed it down to that when driven very hard in under-damped vented enclosures the suspension's compliance didn't quite control the voice coil former from hitting the back plate on the return stroke.

I can never remember this being a problem in any of the sealed or aperiodic enclosures, such as the original mini-onken, or the little 4 litre wedge

 

[samsagaz]

Consider adding helper woofers.

dave

Problemas is the money. No money todo purchase woofers. Justo hace some tweeters At home.

 

[samsagaz]

Problemas is the money. No money todo purchase woofers. Justo hace some tweeters At home.

as "try" to say before... problem is that i dont have money to purchase woofers. just have a few small tweeters and a few ribbon tweeters

 

[samsagaz]

Thanks. Will check the designs! Some todo recommendme?

room are small. and looks like for bipole i need to place the speakers away from walls. 🙁

 

[chrisb]

You might want to take a look a the Castle Microtower configuration - page 2 and 4 of this plan set, I think.
http://frugal-phile.com/boxlib/P10free/microTower-maps-020615.pdf

I've built 3 pairs of this format so far - 2 with the top panel angled forward at 10dg, and quite like them.

If the room is small enough that the system wouldn't be driven to the extremes likely to cause the issues I described above, they might work very well with appropriately revised vent tuning / damping.

Dave - any thoughts?

 

[chrisb]

Well, short answer from Dave to my own question posed above: 7 liters per driver, heavily damped to near aperiodic characteristics, and if need for mounting height, fake the volume with an internal bottom. I'll sketch something up later today.

 

[planet10]

7 liters per driver, heavily damped to near aperiodic characteristics

I'd base it on the box attached: the slot vent can be left as is or damped (i typically use "stiff" open cel foam) up to the point where it transitions to fully aperiodic.

dave

 

[chrisb]

Did we ever build a pair of those? I can certainly remember a little wedgie monopole with a series of small holes in the slanted backside, of which the the location photo escapes me.


I also got to thinking about a derivation on this one as well - as I recall they worked quite well:

http://p10hifi.net/tlinespeakers/FAL/box-plans/Bipolar-bipoles.gif


25 litre sealed - it probably wouldn't take much to tilt the top to a 10dg forward slant - I know I sound like a broken record on that, but I've lived with a couple of pairs of them now, and really like both the aesthetic and sonic performance vs the standard front to back bipole.

Quickie sketch attached - the CSA has been been modified for a square footprint - also just a personal fetish with this type of design. Not shown is internal lateral bracing, the scheme for which can be as simple as a few thick dowels, or as elaborate as you like - guess which I tend to use.

 

[samsagaz]

I'd base it on the box attached: the slot vent can be left as is or damped (i typically use "stiff" open cel foam) up to the point where it transitions to fully aperiodic.

dave

Its the same design that im using now.

So will use 14L for two drivers then...

 

[samsagaz]

ok will build some of these design maybe 25 degree (coz will be easy to use an router bit for that) what abt tweeter, i have small ones, that purchased with the FR125 i remember that was cheap ones plastic ones. and have 5 x AurumCantus G2Si.

is possible to add any of these additional tweeters without made an expensive xover?

this URL http://www.audiocircle.com/index.php?topic=83025.msg801347#msg801347 show some similar design. and some guy say about add an small cap to the 2nd driver, what think abt that? Best Sounding Single Drivers

 

[samsagaz]

well, will start the box this weekend, i will use two of FR125s + one tweeter.
Abt tweeter think that will use the cheapest ApexJr ones (have AurumaCantus G2Si but think that are too much for the FR125S, right?)

will place both drivers in front of the box, external dimensions will be something like 310mm x 138mm x 950mm, this will be something like 26l are of for a sealed box, right?

 

[chrisb]

The FR125s are quite a competent driver - while we were happy enough with the results with the cheapie tweeter shown, I wouldn't say the G2Si is "too much" for them.

 

[planet10]

The AC tweeter was Al Wooley's goto unit for use with the FR125, and Bob had some kits that mated the 2. Not overkill.

dave

 

[samsagaz]

well, looks like is time to use the G2Si then! like 7 years in his shipping box 🙂

What about the crossover? some tip? some cheap way to build it?

As i say before will use two FR125s and 1 G2Si 🙂

like all the old websites down now :/

 

[chrisb]

As Dave said above, Bob at CSS used to have a kit for these, and most likely would still have specs for his XO handy.

Creative Sound Solutions - feedback form


While others may opine differently, I'd avoid going too cheap on XO components - Bob certainly never did, and I doubt the AC tweeter would overlook the sound of EL caps

 

[samsagaz]

well next week will be in USA, hope i can purchase some additional FR125S, and xover parts for the 2way design (or 3 way) im very lost now 😀

was thinking about purchase full finished speakers like polk monitor 70 that are in very good price, but very hard to ship it via airline to Argentina :/

was thinking purchase another drivers and build a new center, front channels using my G2Si but looks waste of money too.

so mayebe will purchase xover parts (i think that bob dont answer my email and i write it two months ago) + more FR125 so can use pair in fronts and center and others in my surrounds

Think that will be a nice choice, right?

 

[samsagaz]

Maybe purchase 6 wr125 to use in fronts and center and use my fr125 as surround and atmos ?

will be great if can combine FR and WR in the same center box!