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Old 2nd March 2006, 11:00 PM   #1
Rafal is offline Rafal  Canada
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Default New idea for FR125S box

Hi Folks,

I want to do some more experimenting and have an idea for a BR box. After using WinISD I came up with a BR design of 16.4l tuned to 48.19Hz with 1 vent (47mm dia and 99.8mm length). does that sound right? I'm trying to get the bass to go low and reduce the size of the speaker wrt OB to maximize WAF.

This is what I'm thinking:

Your input would be greatly appreciated.

Cheers, Rafal
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Old 2nd March 2006, 11:20 PM   #2
Dumbass is offline Dumbass  British Antarctic Territory
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That alignment seems reasonable. You'd have baffle-step losses around 1kHz (?) or so.

I'd build a quick 'n' dirty prototype before building boxes that fancy.

Have you checked out these designs:
http://www.planet10-hifi.com/boxes.html
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Old 3rd March 2006, 12:28 AM   #3
Rafal is offline Rafal  Canada
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Thanks for the tips. I looked at the te planet10-hifi designs but I'm not sure that the BR enclosure would give me the bass that I would like. The minionken would likely go lower, but I'm not sure if I'm in love witht he way it looks.

By the way, what is a baffle step loss?

Thanks,


Rafal
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Old 3rd March 2006, 12:37 AM   #4
2litre is offline 2litre  United States
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Rafal,

Nice idea for the BR's.
To bad you have to give up your OB's so fast?
They looked sweet and I thought you were going be the first to try a crossover and bass driver or 2 with them.

I searched 'FR125S' under loudspeakers/full range last night and, in addition to Planet10's plans, found some very nice designs, especially the HEGGs.

Heggs for FR125S

R/

Jim
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Old 3rd March 2006, 12:47 AM   #5
Rafal is offline Rafal  Canada
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Thanks for your suggestions Jim,

I haven't given up on OB just yet. In fact, I'm currently listening to Diana Crall through them. Sounds very very nice. I'm just trying diferent ideas and I like to experiment.

I may still go for a nice, big bass driver, but I know so very little about XO design, that it's little intimidating.

Cheers,

Rafal
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Old 3rd March 2006, 01:37 AM   #6
2litre is offline 2litre  United States
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Tell me about it!
I've broken with convention a bit and just purchased some Dayton Reference Series RS225 8" woofers for mine. I'm studying baffle loss, roll off points, acoustic and electrical roll offs and my head is swimming. The hard part is finding another person doing something very similar to what you're doing. 2 brains are almost alway better than 1.

All that and the fact that I feel the FR125S's need protection on the bottom end,.. from bottoming out to fast. It has me looking at higher order crossovers to preserve as much of their range as possible. The sum of the quality components for a 12db X-O cost almost as much as the drivers! Make a mistake there and wow, that'll hurt.

As for baffle step info, try these:

http://sound.westhost.com/bafflestep.htm

http://www.t-linespeakers.org/tech/b...tep/index.html

I've also downloaded Xbaffle.xls and Edge freeware. A bit daunting but I think I'm making headway. Like my main / front baffle is 15"x36" and when you plug the FR125 values into Xbaffle at 30" up (762mm) it shows it's output plumit at about 200Hz. Somewhere close to there is where I'm going to have to cross my woofer.

I'm also looking at the 7L ported box plans that Planet10 has available. That's partly why I mentioned the HEGGS to you. The drivers sound to nice to let them sit for long and you may just have to use helpers for the bass.

R/

Jim
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Old 3rd March 2006, 04:28 AM   #7
Dumbass is offline Dumbass  British Antarctic Territory
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Baffle step loss refers to the fact that higher frequencies only "see" half-space (i.e. radiate as if mounted on an infinite baffle) while lower frequencies "see" full-space (i.e. radiate like a point source in 3D). Thus, there is an apparent dropoff of signal below a certain frequency. The larger the speaker baffle, the lower the dropoff point.

IMO the best writeup is on quarter-wave.com (under general speaker articles)
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Old 3rd March 2006, 01:07 PM   #8
Rafal is offline Rafal  Canada
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Quote:
Originally posted by 2litre
Tell me about it!
I've broken with convention a bit and just purchased some Dayton Reference Series RS225 8" woofers for mine. I'm studying baffle loss, roll off points, acoustic and electrical roll offs and my head is swimming. The hard part is finding another person doing something very similar to what you're doing. 2 brains are almost alway better than 1.

All that and the fact that I feel the FR125S's need protection on the bottom end,.. from bottoming out to fast. It has me looking at higher order crossovers to preserve as much of their range as possible. The sum of the quality components for a 12db X-O cost almost as much as the drivers! Make a mistake there and wow, that'll hurt.

As for baffle step info, try these:

http://sound.westhost.com/bafflestep.htm

http://www.t-linespeakers.org/tech/b...tep/index.html

I've also downloaded Xbaffle.xls and Edge freeware. A bit daunting but I think I'm making headway. Like my main / front baffle is 15"x36" and when you plug the FR125 values into Xbaffle at 30" up (762mm) it shows it's output plumit at about 200Hz. Somewhere close to there is where I'm going to have to cross my woofer.

I'm also looking at the 7L ported box plans that Planet10 has available. That's partly why I mentioned the HEGGS to you. The drivers sound to nice to let them sit for long and you may just have to use helpers for the bass.

R/

Jim
Hi Jim,

I like your thinking. I looked up the Dayton drivers and they are not too spendy. I may follow you down simillar path. I was thinking, however, that maybe we can just make a very simple XO. I think the simpler, the better. BTW, what amp are you using?

The other option is to make/buy an activea sub (maybe like a rythmik). Going with FR125Sin OB + a sub has it's advantages and may be easier to implement. It also affords more flexibilit should you choose to change the satelite drivers or enclosures.

I asked my wife, and she didn't agreee to making a larger baffle so I guess I will have to augment the bass some other way. Also, I think I'd like the FR125S positioned higher. closer to the ear level.
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Old 3rd March 2006, 05:07 PM   #9
2litre is offline 2litre  United States
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Rafal,

Right after I put mine in those 15"x19" baffles I tinkered with them in my living room and den (both fairly small) with my old 15wpc Pioneer SX-450. Played with height, distance from walls, seperation, rugs, etc. I was listening to all types of music, Santana, Steely Dan, George Benson, Andy Williams, Willie Nelson, Deep Purple, Brazil 66, Stanley Jordan and my crooner AM station KIXI-AM. During all that is where I experienced how fast they would bottom out.

Then I remembered my Boston 7" sub. Hooked that up and loved it! Set at about 80Hz and 1/3 gain I had sweet sound to 40Hz and I didn't have to stress the FR's so much. Took it down at the end of that weekend and I've yet to hook it all up again. So, I've done the active sub route and found it very satisfying in my small rooms. I'll try it again after I get the 7L boxes done and more capacitors to try.

I agree with your desire to use simple X-O's. I like them too. Generally they're easier on the brain and wallet. My 3-way NoBox is crossed low to mid at 125Hz, 1st order. I'm going to 'borrow' those components and try them out on the FR / RS set up. If it does well I'll buy some better components of the same values.

Sounds funky doesn't it? I mention that I really liked the sound of them with the active sub yet I'm still screwing around with a straight OB idea. Well I just want to try it all out. If it doesn't cut it, well I can use the RS225 as the bass unit in a sealed or ported system, either with or without plate amp. Heck, the 911 wasn't Ferdinand Porsche's first automotive design, he cut his teeth on the VW Beetle.

R/

Jim
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Old 3rd March 2006, 05:11 PM   #10
westend is offline westend  United States
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I started with the FR125 in OB, as well. I tried a few different baffle designs. At the same time I hooked up a few different drivers to better understand the OB sound. Using the FR125 in OB in an almost nearfield (6-10) alignment with the FR125 mounted low gave me the best results.
I have migrated to an aperiodic design and use the boxes for HT sattelites at present. The thread about the Northcreek aperiodic design and pics of a couple builds are here: CSS FR125S ... production units playing now... A thread on filters and crossovers for the FR125 is here: FR125S Measurements and Filters
I believe the aperiodic enclosure suits the FR125 and my use fairly well. Trying to get a lot of bass and low end dynamics from a 4" driver is like teaching a pig to sing...doesn't sound good and pisses off the pig.
Augmenting the FR125 would probably yield good results. The dipole from Planet 10's site might do it for me with some music. I didn't think the FR125 needed any help on the higher end but some have added a tweeter.
Good luck on the build.
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