Construction help ...

[Gregory Isaacs]

Hi,
I've decided to go for the CSS FR125S speaker for my first serious project, I hope.
Since I've screwed some vintage Isophones in an open baffle for testing I really can't forget that impression they made on me and my T+A loudspeakers appear a bit dull to me no.

Ok,now to the facts:
- I have a small listening room and my listening position is about 1,5 meters
away from the speakers
- I can go for a width of speakers for about 50 cm, more would
take away too much space
- It doesn't matter how high the speakers get, my ceiling is at about 2.5 or
2.6 meters
- There won't be a lot of space to the rear wall

Of course I want to get the best out of this situation without wasting too much wood for half-backed plans and as a beginner my experience in understanding frequency curves with edge is rather shallow.

As mentioned above I would like to go OB, but some kind of horn would be interesting too.

Any tips for a realistic goal to achieve or things consider with this project would be great.

[pinkmouse]

Points 2 and 4 just about rule out OB. I would wander over to the BIB thread and see if they can help

[Gregory Isaacs]

Yes, I've read about that. What gave me a little hope was that I've seen a lot of pics on the net with OB's rather close to the rear wall.

[Scottmoose]

True, but they will probably tend to be somewhat wider, and frequently have a bass helper near the floor.

[Gregory Isaacs]

I can't explain why I dislike woofers, but I thought of having bass drivers in a box and the rest above OB.

[johninCR]

I've built a lot of OB's and none have been 50cm wide or more. The closer you are to your OB's the wider they will be in terms of dipole roll-off, AND the influence of the rear wave is further reduced when the effective baffle width is significant compared to listening distance.

In one desktop OB setup, my desk was facing the wall and I had one edge of each baffle touching the wall with a listening distance similar to your 1.5m. My biggest problem was the impact of my monitor on the soundstage. Without it I had a huge wide soundstage. When I tried to place those same OB's out in the room, I had to add much more bass augmentation.

I've yet to be unable to make an OB work in any placement. That's one of the things I like most... they're so tuneable.

[Gregory Isaacs]

Thanks for the input. I'll try some different setups with the drivers in cardboard baffles for testing to listen at the results. Seems to be the only way.
BTW is there any literature on OB?

[johninCR]

Originally posted by Gregory Isaacs
Thanks for the input. I'll try some different setups with the drivers in cardboard baffles for testing to listen at the results. Seems to be the only way.
BTW is there any literature on OB?

http://linkwitzlab.com/

and

http://musicanddesign.com/tech.html

cover the science.

[Gregory Isaacs]

Thanks, I new the Linkwitz site, but not the other one. I'll dig into some theory now.....

[Gregory Isaacs]

On monday my Fr125's arrived. The first thing I did was to mount them on cardboard about 120cm x 48 and 15cm deep - it was a box.

The sound really impressed me and I listened to music the whole week to get into this sound and verify where there could be weaknesses or improvements could be made.

Then I unfolded the box and only left the top bent and unfolded the sides which was better, as it sounded a bit suppressed.

Today I mounted them on plywood 90cm x 80cm like those JELabs open baffles having a lot more bass and mids than before. It's not completed yet, but I think it's the design I'll choose. But there's still some listening to do