The Fix

[Grainger49]

And I was thinking Doc invented the decade box.  But wait!  It has a real audio purpose!

I'm in too! 

BTW, I didn't put you in the group with Dyson who re-invented the air horn, has a fan with no blades (there are 2 million fleas in the base farting to create the air), and advertises it as something new.

 

[Chris]

Ok Thank you PB, I will leave those particular speaker models well enough alone as they are..

 

[jrebman]

It's probably obvious from the pics, but can I assume that this is a line level device -- between pre and power amps, as opposed to a speaker level device?

Cut-only filters are the way to go, IMO.

I'd love to try this with a buddy's pair of zigmahornets as well as my Nagas.

Cool idea!

-- Jim

 

[Paul Joppa]

Yes indeed - passive, cut only, RC (no inductors).

The impetus for getting involved several years ago was the observation that many home-brew single driver systems needed some baffle step correction, which was (and still is) usually done at speaker level with a choke/resistor parallel combination. This combination reduced the effective midband efficiency to less than half of what it had been, meaning you needed more than twice as much amplifier power. This was a big problem when used with flea-power SET amps, and caused a lot of 45-powered speakers to suddenly need 300Bs. In particular, we were working on the SEXy Speaker at the time, which was being developed specifically to be something affordable that could play loud with a SEX amp. You can still find a very early, non-adjustable version of what became the Fix on that page:

http://www.bottlehead.com/loosep/S.E.Xy%20speakers.html

 

[jrebman]

So working under the principlle of "there's no free lunch", what are the impedance matching and cabling length considerations with this box between say pre and power amps?

-- Jim

 

[Paul Joppa]

My preliminary spec is the source impedance should no greater than than 4K (the output impedance of Eros, Reduction, and Quickie with PJCCS) and the load should be no less than 100K (the input impedance of most of our amps). Cables on the output are preferably 0.5 meter (1 meter if low capacitance). These impedance restrictions are the price you pay for a passive device.

Final specs will appear with the listing on the product page.

 

[HF9]

Very cool, looking forward to trying this with a pair of Frugal Horns

 

[Evan]

HF9-
Once you do try it with the Frugal Horns please post your impressions. I am going to be building a pair using Fostex FE126en drivers in the near future and I also thought this might be a worthwhile experiment. Shoot, for the price I could just experiment for myself.

 

[Wanderer]

.... They are immaculate pairs of Acoustat 2+2s (3 pair) and Infinity RS IIIs...

I may be out of my depth but my understanding is dipole speakers do not exhibit a baffle step loss and would not need correction. As I recall Acoustats ae dipoles. 

 

[Paul Joppa]

...
I may be out of my depth but my understanding is dipole speakers do not exhibit a baffle step loss and would not need correction. As I recall Acoustats are dipoles.

True - dipoles lose bass for a different reason, and with a different frequency response.

 

[Alonzo]

Paul,
I've purchased one for my Frugal Horns,  I also have a pair of SeXy Speakers, will the settings overlap the BSC previously put out for the SeXy speakers so I can remove my inline one?
Alonzo

 

[Clark B.]

I've gotta chime in here one more time to say that I've tried out alot of caps for high frequency tasks like single component tweeter crossovers with some super high end Fostex drivers (FE208ES-R and T90A-EX).  I eventually abandoned the tweeters, BSC, or, really, any treble adjustment because I couldn't find a cap, resistor, l-pad, etc. that sounded "right" for the tweeter. 

That is, until I heard The Fix with the Orcas.  The sound of those polystyrene caps doing their job at the line level was so effortless and transparent that I just don't see a way of getting a tweeter to work out as well unless it was way higher end than even the T90A-EX or something.  Paper cone highs can sound really natural and smooth, but are always locked in exactly the same proportion with the rest of the fullrange driver and/or often become directional the larger you go in cone diameter.  Metal tweeters just tend to sound, well, metallic to me no matter what, and ribbons are nice, clean and sound really "deep" to me in a good way, but seem to outpace most of the direct radiator woofers that they are mated to.  Overall, there are so many compromises out there.  I could go on and on, but suffice it to say that I think it is really tough to "tweet." 

The Fix is a really compelling tweak for me as an FR guy because I can just get more highs from my favorite driver if I needed to.  For that matter, its great for anyone who needs a different frequency response from any old speaker, Orcas or otherwise.  For instance, for speakers with the "bad sounding" kind of speaker level HF and LF boosts, you could zero those out, and use The Fix instead...  Lots of possibilities.  I really wish I had The Fix back when I was listening to Fostex 6" ers - Fantastic drivers in many respects but rolled off in the highs to my ears.

Cheers!

-Clark

 

[Alonzo]

Will this be out (delivered) in December?  I anticipate another government shutdown come January so I'm lining up my projects...

 

[Paul Joppa]

..., will the settings overlap the BSC previously put out for the SeXy speakers so I can remove my inline one?
Alonzo

Yes indeed, it is the same circuit except for having more control. Even for the SEXy, I strongly recommend trying all the settings to find what works best in your room. (Also the Fix has some pretty nice caps, chosen by PB.)

 

[Doc B]

We are waiting for some parts to arrive and then the guys will shoot the manual. Once that is ready we will begin shipping, probably in a week or two.

 

[Natural Sound]

I'm looking forward to the comments from the community when this is released. I'm especially interested in how they work with Orca's. I personally don't think that the Orca's need Baffle Step Correction like my former speakers (SEXy). However I'm currently set up in a "sonically challenged" room. I'm thinking that "The Fix" might be able to correct some of my room anomalies that I'm unable to solve with room treatments. It certainly is a very affordable way to find out.

 

[pendergast]

Hi,


This seems quite interesting. Somehow, it reminds me a bit of this design used on old Quad preamps. I may be wrong on this though.

So my actual set-up is a SEX purchased and built in 2006 (I suppose that is a 2.0?) which had an iron upgrade (aka "enhanced SEX"). The amp is connected to a pair of Fostex 206 ES-R (http://www.einklang-audio.com/treiber/fostex/fe206esr.pdf).

Now, the lower frequencies of the Fostex are decreasing 'seriously' at 200 Hz (see attached tech document). I have connected a subwoofer driver (an Augie Silver Iris) to compensate for the lack of bass.

So if I understand correctly, using The Fix, I could go as far as changing the cut-off frequency of the Augie to a lower level because I might raise the lower frequencies db on the Fostex'?

 

[Paul Birkeland]

I'd set the Fix on the widest baffle setting and +4dB of BSC.  This should certainly help with your setup.

 

[Paul Joppa]

The linked specifications are probably with an IEC standard baffle, which is a largish open baffle, and driven by an amp with a very high damping factor. If you have an enclosure, it will significantly alter the response below 200Hz; the usual design goal is to make it flat to as low a frequency as possible.

 

[Hank Murrow]

I'm thinking that "The Fix" might be able to correct some of my room anomalies that I'm unable to solve with room treatments. It certainly is a very affordable way to find out.

Dear Natural Sound; If you got a "FIX" could you report on how your Orcas responded to the corrections available?

Cheers, Hank