How To Build a FRFR Cab?

Q

quark

Experienced
There's lots of discussion about FRFR and the various choices available. But I was always under the impression that building a FRFR speaker (the holy grail of high-end stereo systems) involved more than just building a box and throwing a driver into it. I never hear any discussion about what the newer FRFR offerings have done to achieve FRFR status. Seems like all the drivers are off the shelf and similar to the drivers that you find in standard cabs, the boxes look similar in size and shape to standard cabs and wedges, so where is the engineering "magic" that somehow integrates box, driver, and cross-over into a system that gives you a flat frequency response over a wide range.

I suppose that one answer might be that typical guitar cabs are the ones that intentionally deviate from FRFR to achieve their particular qualities and that if you don't do those things, FRFR is what you get by default. But somehow, I doubt it.

Anyone have any thoughts about what it takes to make a FRFR speaker and what the newer FRFR offerings out there have actually done to achieve it?
 
Following this thread! I'm also curious how the enclosure effects the speaker in a FRFR-environment.
 
There used to be a member on this board that could or wait... maybe might tell you how that is done but it would take way to much time :lol.
 
that is one giant can of worms too open!:)

as far as guitar cabs go,when Jim Marshall and company started making the 4x12 cabs,i doubt there was anymore research than making a square box with handles big enough to fit the speakers in.as guitar players. i think we all have just gotten used to the sound they produce and it has become the standard.

best suggestion is to take some courses in sound engineering.there are also a few decent programs you can use to design a box,Eminence designer,Winisd pro,Leap,and many others.do a search for DIY speaker box and you will find many more.

some use the expression "jumping down the rabbit hole",this is more like jumping into the Grand Canyon.;)

easiest way out,if you must build your own,find an FRFR box you like the sound of and reverse engineer it.many companies give there dimensions and measurements on a pdf spec sheet.the box construction in of itself,is just basic woodworking.the bracing,inner volume,port tuning,damping material etc,,is were the attention to detail matters.
 
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I guess my question was not really how to do it myself but does anyone know what some of the newer companies offering FRFR are doing to achieve it. Some of these companies don't seem to have much of an engineering staff, technical expertise in the area, measurement equipment or labs to pull this off ( all my assumptions of course and I could be dead wrong ).

I thought maybe some forum members who bought these FRFR speakers might have gotten some info they could share or some members with a background in acoustics/engineering could chime in whether it was an easy or difficult goal to achieve. The ex-forum member referred to said on another forum that its just not a question of throwing drivers into a box. Otherwise you'd just be paying ~$600 to build a box to hold a ~$200 driver.

I'd like to get some confidence that the recent new offerings in this area are not just doing that. Maybe its a question I should just ask them directly before I lay down some cash.

Thanks
 
quark said:
I'd like to get some confidence that the recent new offerings in this area are not just doing that. Maybe its a question I should just ask them directly before I lay down some cash.

Thanks
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and each one of them would tell you "of course,we have done extensive research and development,plus thousands of hours of lab testing."

you get what you pay for with FRFR.just like with guitars,you pay 100% more for 10% better.and if that 10% is flat response from 50hz to 16000hz,guess what?
 
You could always try the plans they have on the B & C website. They have suggested plans for all their speakers, and in monitor and mains formats.
 
quark said:
The ex-forum member referred to said on another forum that its just not a question of throwing drivers into a box. Otherwise you'd just be paying ~$600 to build a box to hold a ~$200 driver.
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That has been said here as well and he would be correct! All joking aside it is far easer and better to leave it to the people / companies that have the tools to do the job correctly. Building a true FRFR cab is so much more then a box, speakers and a crossover DSP being some of it as well. By the time you factor all your labor and hard costs you may as well go buy something that is already done and done the right way.
 
I didnt build one but I did a test (mod) with one of my Hermida ported 1x12 and it works great. I installed a Eminence coax in it, did a rta test and it was almost flat from the beginning...there is nothing wrong with trying modding or having fun building a cab, you never know what can come out of it...as a matter of fact NO ONE MAKES A PERFECT CAB or a cab that is good for all, someone that tells you different is a salesman...it all comes down to personal taste.

 
Galo said:
I didnt build one but I did a test (mod) with one of my Hermida ported 1x12 and it works great. I installed a Eminence coax in it, did a rta test and it was almost flat from the beginning...there is nothing wrong with trying modding or having fun building a cab, you never know what can come out of it...as a matter of fact NO ONE MAKES A PERFECT CAB or a cab that is good for all, someone that tells you different is a salesman...it all comes down to personal taste.

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HI!
Which eminence coax did you use? Beta 12CX?
Thanks!
 
Galo said:
I didnt build one but I did a test (mod) with one of my Hermida ported 1x12 and it works great. I installed a Eminence coax in it, did a rta test and it was almost flat from the beginning...there is nothing wrong with trying modding or having fun building a cab, you never know what can come out of it...as a matter of fact NO ONE MAKES A PERFECT CAB or a cab that is good for all, someone that tells you different is a salesman...it all comes down to personal taste.

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Really cool! But to be fair, hardly looks like a good room to measure speaker response, no?
 
It actually is pretty much putting an off the shelf speaker and crossover into a box with some nice amp and DSP to help correct the frequency response. The only thing is that that box has to be very carefully designed in order to sound good and be flat. FRFR are just PA speakers, we are still using the same box designs we were a long time ago. The only reason newer FRFRs are better is because amplifier power is much cheaper and DSP makes corrections that used to be impossible.
Also, the FRFR speakers marketed for use with guitar modelers aren’t really that different than normal PA speakers. They are just PA speakers that are marketed diffferently. Even the XiTone and CLR speakers aren’t really a new idea they are using the same concepts as other coaxial speakers such as the RCF NX12. They come at a cheaper price point but it’s not like they are any more FRFR than the PA speakers that are already out there.
 
One that is treated to control resonance and reflections. Anechoic chambers are often used for precise measurements of cab and driver performance to eliminate the room's influence on the sound.
 
To make a long story short, most of the products on the market aren't all that flat. Some of the better ones incorporate DSP amplifiers with equalizer curves dialed in to level things out, and with the passive boxes you get what you get.

In terms of designing one, you can get in the general ballpark with well chosen woofer and tweeter, and a suitably designed crossover. Enclosure design isn't rocket science, not in live sound. Just get the overall volume right (use a speaker modeling tool) and figure out how much damping to put inside. From there if you have a DSP amplifier then you can just measure and EQ until things are close enough. Going beyond that gets into serious speaker design.
 
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