diyAudio Full Range Reference Project

frugal-phile™
Joined 2001
Paid Member
Re: is it too late to ask ?

Bigun said:
question: still not sure if there is much difference (listening) between the monopole and folded monopole ? The straight monopole looks like a good option for wall mounting.

Mounted on a wall, i'd go with the straight monopole... the folded one is to give an option that is more "normal" cosmeticallt

question: the complexity of the fonken cabinet isn't a worry so the comments about it being better than the monopole caught my interest. It may be better, but is it marginal or more of a 'matter of personal taste' in terms of the sound ?

We asked that question too... Why would we build a Fonken if the diyA ref was even close, so we compared the diyA ref folded monopole we built for Chris' mom to a set of Fonken, We are still building Fonken. Ir has more finese and control... and certainly enuff to warrant the extra effort.

What amp do you have?

dave
 
Re: Re: is it too late to ask ?

planet10 said:


What amp do you have?

dave

My current set up is simple stereo:

Bryston Integrated B60
YBA CD
Dynalab Tuner 101A
PMC FB1s

but the basement set up for HT is yet to materialize. If/when I DIY some speakers I may be enthused enough to DIY a Gainclone to drive them.
 
So I am building this one, could someone please tell me if I can put the port on the back withoug messing it up. I know in normal br cabinets this is no problem, but then on this one, I don't really know what kind of cab it is ;)

also, would it matter much, if the port is something like 36-37mm diameter, instead of 38? should I adjust the length?

Thanks for help!

Rob
 
Here is a folded variation. Things are a bit tight around the driver, so we turn that into an advantage by making the partition the brace,

dave

Writing in with some listening impressions now the drivers have settled down.

The cabinet itself is very easy to build, and having the driver cutout on the fold makes stuffing adjustment very easy.

I use them in a bedroom, backed with a subwoofer. Crossover is ~80Hz, though the Fostexes themselves have output down to more like 60Hz in room. They're driven with an amp6-b from 41Hz, 12v supply at 5A. Plenty. Source is Apple Lossless from my iPod through a dock into a headphone splitter, then into each amplifier.

Built of 15mm MDF, yet vibrations aren't a problem until they're really pushed.

The cabinets were stuffed at the tapered end, with some comming around the driver (so it's level with the bottom of the cutout of the driver). This helped to stop internal reflections comming through the cone. Some bass is lost to adding the stuffing, but the improvements in the midrange were, in my opinion, worth this loss. Stuffing the ported end of the pipe meant some of the lower midrange was also lost, so I'd recommend stuffing the tapered end and around the driver, to avoid them sounding over-thin.

Anyway, the sound. The midrange is... Sublime. I struggle to describe it without using the usual words. Here goes... They're very natural and coherant - the FR magic is definitely there. They're revealing enough to lay bare any problems with recordings. Yet the huge amount of detail on offer doesn't detract from the performance (some speakers can end up over-analytical). The more I listen, the more I hear.
The treble is extended (certainly no need for a tweeter, even off axis). Metal things sound metallic (all the harmonics are present and correct); the sound of a pick hitting a guitar string is clear, and very very close to how it should sound (I play guitar, so it's easy to tell when the sound's right).
With such a small cabinet, of course bass won't be as extended as one might like, but I expected this. Still, as I said, they'll go to around 60Hz in room (more like 80Hz after stuffing). When pushed close to a wall, the bass becomes inflated and boomy. Not the sound I was after, so the combination of a crossover and stuffing has killed this off effectively.
The soundstage they create is truely amazing. During one particular violin solo (recorded at a medium distance through a stereo mic), you can hear the violinist move around (bending down and straightening up as they so often seem to do). With a different, 3-person vocal piece, they somehow manage to place one singer a foot right of the right speaker, another is sat on my desk, 2 feet to the left of the left speaker, and the third is just off-centre. I still find it amazing that they can position these voices so seperately, yet maintain the music as a whole. The entire experience is something to behold.

The only major downside to these is the limited maximum SPL. Despite being fully enabled, they still display stress when really pushed (full power from the little amp). However, for smaller-scale listening, they really are something else.

Chris
 
It -- or the BD-pipes i've been living with -- inspired the port & bass. The 3 points are definitly inspired by your design.

A lite version of GMs pipe attached. He has donated the design to the transmission line speakers site with the intention that plans will be distributed on a "by donation" basis... even without having the page up or the details of distribution worked out i've already had one donation of $25 for the plans.

dave

hi,
i'd like to have more information about this project but i don't find anything on the web.
May i have the dimensions of all wood panels?
thanks a lot
 
I've been living with these speakers for some time now.

I'm still using an amp6-b from 41Hz audio, source is an iPod playing LossLess, or a CD player occasionally.
I've also built a 4th order active crossover for them (80Hz), having recently built some tapped horns to cover the lower octaves.
Now they're crossed over, the maximum SPL issue I mentioned earlier isn't a problem - they go loud enough to annoy my parents, and remain clear when pushed. Treble does become a little forward when you really turn it up (keeping up with a hairdryer sort of levels), but the screamy cone break-up (3-5kHz) generally associated with paper coned drivers just doesn't show itself up.
As a whole, these speakers could be done for much less money than stuff from a typical "hifi" store, but I'm yet to hear a commercial design that comes close in midrange detail.

Top job Dave.

Chris

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