Designed by Rabbitz

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Hi folks,

Just want to share my experience with the FR125S driver. It's long by necessity...

Rabbitz and I are good mates and as such he decided to visit me recently - we'd never met but it felt like we'd known each other for years when we finally did.

I'd wanted to hear some full range's to hear what all the fuss was about, that and I had a hunch that it was the sound I was after - smooth. Rabbitz sent a pair of FR125S drivers down so I could knock up some boxes before he arrived, to listen to together. Needless to say that things happened and I didn't make them in time. In actual fact they were made while he was here!

It was a standard narrow baffle bass reflex of about 13L. A bit of stuffing on the rear and bottom panels and that was about it. They were plugged into the system and the music was turned on. I can't be entirely sure but I'm fairly certain Rabbitz was watching my expression which was, sad to say, not terribly good. Drums were recessed, vocals a bit muted and the mid-range was awol.

Trying to think of a polite way to say they sucked rather-a-lot it dawned on me that the valves in the pre were the wrong ones (long story) - they were swapped out and the system powered back up for another try. Well stuff me if it didn't make me feel all giddy inside. Several notes were all it took to be converted, and here I am! I wont get into all the details of sound, many of you already know. They were smooth though and slotted in beautifully and a pair of FR125S drivers were on the ever growing shopping list.

<insert a small sub-plot>When Rabbitz' trip was over he told me before he left to hang on to the drivers for a couple of weeks to be sure they were doing what I thought they were doing - enjoy 'em basically. That and the airline wouldn't let him take magnets on the flight. Cool I thought :D A week or so later we were having a chat on the phone and I asked if he'd like me to get the pair I was soon to order sent to him, so I wasn't sending back the now used drivers. "Hang on to them for another week or so" he says. "Oh hell" I reply, thinking he is going to get me to try out a TL or similar concept, before sending them back.

Several days later I get an email with a password protected word doc and a clue as to the password. I didn't have time to 'crack' it before leaving for tech. Rabbitz rings that afternoon, probably expecting a grand reaction as a result of the document - he didn't get one as it hadn't been opened... so it was opened while we were on the phone. "Five shown but only two are yours... in the boxes you built"... Happy ******* birthday indeed! Talk about overwhelmed!!! I felt like a mini-king for days.
</insert a small sub-plot>

Thinking a retro-ish (slim-line, wide baffle) shaped box would suit them Rabbitz came up with dimensions based on golden ratios and various other voodoo art stuff. They were completed yesterday and stuff me if they don't sound even better than the narrow baffled box. More open all round, a fuller bottom end and the mids are a little more forward which brings the overall balance up nicely. There's a few things I'd like to try but can't drag myself away from the things they sound so damn good! WOOHOO!

A heartfelt thanks to Peter :D

An externally hosted image should be here but it was not working when we last tested it.
 
Awwwww.... you've got me blushing and turning red. That's what mates do and if you can help someone enjoy their tunes more, so be it.
 

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Here's the drawing of the box. Port not shown but can be located on the sides or bottom. The driver cutout on the baffle needs to have a radius or bevel on the inside to assist with airflow.

Lazyfly has reported that 40mm damping works well and any more is detrimental. He still has to do the stand for these and think about port location with that in mind when constructing.

The difference in sound between the slim wide box vs the deep narrow box is interesting.... almost same volume and Fb. Maybe someone has an explanation as all I can come up with is lower baffle step and difference in back wave handling and reflections.

Hey... If I want to be a pink fuffy bunny, then I can. :D
 

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Hi kristleifur, the rings were something Rabbitz hooked onto that he'd seen in some old Mission or B&W or both. Something about breaking up the resonances immediately behind the driver, though he also noted that the basket design kind of has the backwaves shooting 'sideways' I'll let Rabbitz elaborate on it all as my knowledge is a spit in the ocean compared to his :D

I had a couple of lovely sheets of iron-on blackwood veneer (baffles) which wasn't quite enough to do the sides, top and bottom too. Tassie oak/vic ash was used to achieve the contrast. The b'wood leaves were consecutive which is great, sadly having hot melt glue applied to one side means you can't flip the leaf over to mirror the grain, live and learn. A cabinet scraper and 5 coats of Danish Oil (urethane based) applied with steel wool finished them off.

Thanks for noticing the "70's feel" as that was what we were trying to achieve :D

Cheers!
 
Hi maxxdd,

I like the port at the bottom too though Rabbitz will testify I've been mildly complaining ever since as it limits the stand options. With regards to stands, I haven't done them yet :whazzat:

A short listen showed that with the cabinets sitting on some 400mm high metal stands the plate covers the port. Quite a bit of the bottom end disappears and the mids lost out a bit by sounding a little recessed. I'll plug the ports properly and have a proper go later on this evening, I'm guessing covering vs plugging will make a fair difference as there'd be air leaks the way I did it.
 
Maxdd & onespeed, I've had a good listen to this speaker sealed, and obviously not sealed :)

Initial impressions were that there wasn't a great deal of difference aside from what you'd expect, tighter bottom end though less of it and the driver working harder. There was one thing however that was improved by a margin and that was imaging. It was noticeably more precise which suits the speaker remarkably well! The music was a shade or two tighter.

That's the biggest plus but the loss of bass weight and extension makes it a tough choice as I personally love the tonal quality of these down low. I have a M22 8" Vifa 'sub' that goes down to the low 30's and I much prefer that to be off when these are playing.

So it's a bummer as that imaging makes the choice a little bit harder, bass-reflex or sealed? These will likely live happily without a sock in the port but that imaging does have appeal and it's nice to have it both ways :)
 
one1speed, it's great to have the choice and tried it again last night just to be sure I wasn't making things up. I wasn't though do prefer the port opened.

A tip: Put the port on the side or rear (with an elbow)!

fergs, if Rabbitz were to perform a true random act of kindness - well said by the way - he'd have put me out of my misery while he was visiting! *mumble* *port placement* *mumble*

:D
 
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