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

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Hi everyone!

I'm new to this thread and would therefore like to introduce myself: I'm a university student from Switzerland with a great interest in audio electronics, etc. I've built a preamplifier with integrated variable subwoofer crossover, a subwoofer amp and the (sealed) subwoofer itself so far. My Intention was to make up for the lack of low bass of my Tannoy Reveal studio monitors (I'm a music producer, too) and go for a sealed monitoring system. Now I got really interested in fullrange drivers. I've already ordered the FR125S from Germany and probably will put them into the standard bass reflex enclosure. This way I could seal them if desired and cross them over at 80 Hz to my sealed subwoofer. Now my question is: How linear are the drivers? My Tannoys are very linear and come close to the Mackie HR824 except for bass reponse. Has anyone made measurements of the frequency response of the bass reflex design?
 
I just ordered a pair of FR125's from Creative Sound. Has anyone tried them on an open baffle?

I was thinking of using the FR15S on an OB above 250 Hz, crossed over to a pair of WR125ST's, with dual subs below. The WR125ST's would be used in a sealed box, with either both firing forward, or one forward and one back (push-pull). So I guess you could say it would be semi-dipole or full dipole.

OTOH I don't know if I will like dipoles, so the backup plan is a totally enclosed, forward firing system.
 
Landroval said:
What actually is the point of dipole in a box with two drivers (push-pull)?

I don't really know Landroval, I'm making this up as I go along. Comments are more than welcome. :)

I thought it might give a more coherent blend with the OB FR125S, if the frequencies covered by the WR125ST's (70 to 250 Hz) were also dipole. I'd need a huge baffle and bigger drivers if I wanted to go OB from 70-250, neither of which I want, so I need a box. Maybe it would be better just to stay with front-firing from 70-250?
 
audiobomber said:
I thought it might give a more coherent blend with the OB FR125S, if the frequencies covered by the WR125ST's (70 to 250 Hz) were also dipole. I'd need a huge baffle and bigger drivers if I wanted to go OB from 70-250, neither of which I want, so I need a box.
Dipole is a dipole whether it's OB or push-pull-box. You'll still need the 5 foot wide baffle to go to 70Hz.

A bipole box would be totally different.
 
planet10 said:


I hope to have a set of FR125s on my plexi open baffles by the WE.

dave

Terrific. If you wouldn't mind, I'd love to hear the details and results.

planet10 said:


Depends... we did a fostex push-push bipole XOed to a dipole Heil ribbon. They are decent.

dave

Geez Dave, I'm going for KILLER, not just decent! :D

I know you're at least as sensitive to coherence as me, if not more so. What do you think of mixing radiation patterns like this (semi-dipole, semi-bipole etc)? Does it work, i.e. is it still coherent?
 
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audiobomber said:
If you wouldn't mind, I'd love to hear the details and results.

I'm going for KILLER, not just decent! :D

We really liked them when we made them... but after living with the midrange coherency of the likes of the FR125 & FE108ES ....

Some pictures of the Heils can be seen in my Audio Vendor's Bazaar thread

http://www.diyaudio.com/forums/showthread.php?postid=453238#post453238

the original AMTs were (sorta) bipole (with a PR on the back). Below baffle step all boxes tend towards omnipoles.

dave
 
planet10 said:
We really liked them when we made them... but after living with the midrange coherency of the likes of the FR125 & FE108ES ....

I have pure full-range coherence in the upstairs system (RAW-1F's fronted by some pretty nice electronics). What I'm trying for in my main room is nearly full-range coherence, but with the power of a multi-way active system.

planet10 said:
Below baffle step all boxes tend towards omnipoles

Good point!
 
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LilMik said:
i have a quick questione regarding the fr125s in the mini-onken: what do you do to compensate the baffelstep that begins at 600 hz?

Martin has some good tools for figuring out a BSC compensation circuit. I haven't played with one for the miniOs yet -- my general experience so far being that most of the time i don't like what happens with the circuit in place (and a predilication to bipoles). I still keep hauling out the Ls & Cs & Rs thou and play ...

dave
 
planet10 said:


Martin has some good tools for figuring out a BSC compensation circuit. I haven't played with one for the miniOs yet -- my general experience so far being that most of the time i don't like what happens with the circuit in place (and a predilication to bipoles). I still keep hauling out the Ls & Cs & Rs thou and play ...

dave

It's really not as simple as just BSC. :D
 
I got to hear the Raw Acoustic CSS Speakers at CES in the Adire Audio room, they were wonderful. They were in a small ported box.

I was just wondering what your thoughts would be in putting the FR125S in an enclosure like this: http://home.indy.net/~gregdunn/dynaco/components/speakers/aperiodic.jpg

The first chamber where the speaker is mounted is separated by an aperiodic vent that vents into the second larger chamber. This way, the bass output from the aperiodic vent will not cancel the bass output of the driver as occurs in a single chamber aperiodic enclosure.
 
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