Big coaxial box

However the mid range is muffled/bumpy

Yeah, its specs dictates a high average power be used combined with a 'tight' rear chamber to properly damp it as shown in their recommended high tuned cab alignments, so for the home it ideally needs at least a BP4 with BP6 [Karlson slot TL] a step up; otherwise a well stuffed sealed or ~aperiodic alignment, though of course they opted for simpler cab alignments for the home.

These are also good choices for the [relatively few] driver tweakers among us. ;)
 
Care to share the the speaker dimension/volume/ports etc?
The box I build turned out a bit small, 60x40x30cm outer, double baffle etc resulting in about 45l box. I just took a port I had. Works decent but I’ll probably build a larger box soon (same dimensions but inner = 74l). The same new box is where I wanted to try the Celestion but I’m having second thoughts and I still have a long way to with sim, measuring, crossovers and finish so I’m not sure I want to go with a set of new drivers yet before I learned to get max out the Betas.
Anyway here is my amateur box thread for the beta:
Eminence Beta 12CX/ASD1001 coaxial upgrade modification options?
 
fabricadetabaco said:
The box I build turned out a bit small, 60x40x30cm outer, double baffle etc resulting in about 45l box. I just took a port I had. Works decent but I’ll probably build a larger box soon (same dimensions but inner = 74l). The same new box is where I wanted to try the Celestion but I’m having second thoughts and I still have a long way to with sim, measuring, crossovers and finish so I’m not sure I want to go with a set of new drivers yet before I learned to get max out the Betas.
Anyway here is my amateur box thread for the beta:
Eminence Beta 12CX/ASD1001 coaxial upgrade modification options?
Nice. Thanks.

Especially the #16 post by GM is interesting. The Adire HE12.1. I know its an old design and I would have to come up with my own crossover but it still interesting nonetheless.
GM said:
Yes, this is one way, though IME it still needs damping, though if the carpet pad/carpet is dense enough, but then it can roll the bass off too much and why I switched to TLs.
Damping where? Inside the speaker or under the port?
 
Hi,
why can’t I seem to be able find any info or plans or even many photographs of boxes running single big (12”, 15” and beyond) coaxial drivers?
There was a thread a few months back listing several very nice 12” coaxial drivers but what do people use these for?

Also when calculating for a new box how should I go about it? Use only the woofer side of the data sheet for input info?
why suffer the issues of a large coax all it will do is play louder and go lower than a small one will. I am running the best of the current Tannoy range of Dual Concentric XT series. They are astounding in terms of integration and presentation of stage image and height of image, the bass is surprising. Include multiple small subs to control bass pressure in the listening room. I have the two smallest models which are a stand mount six inch DC and the Mini XT which has a cone only 3.25 inches across. All are paper cone true dual concentric. The Mini XT has the smallest tweeter diaphragm about 20 mm and it has the best stage and image. These are amazing for near field listening. My local dealer has a wide range of new Tannoy up to the Canterbury and I find the XT series to be the best of the best.
 
I do understand. The take away should have read make your coax as small as what will meet your volume level requirements as this will lessen the issues associated with larger coax's to a minimum. Then bring out the big boy woofers and use them for what they do best, making bass in large quantities. You still get lots of big cabinets you also get superb stage image and spatial qualities. Carry on and design some big rigs because they do stuff small ones just can't.
 
why suffer the issues of a large coax

Indeed! While the pioneers started with huge 500 Hz fully horn loaded speakers, finally settling on 800 Hz XO horn/15" woofer, 1500 Hz horn/12" woofer with ultimately the most sought after, a co-ax 1500-1600 Hz horn/15" woofer [all woofers extremely wide BW], they concluded that an 8" proper tri-ax [W.E./Lansing/Altec 755 series] was the ideal for highest speech intelligibility.

Fast forward to the '50s and history was made again by taking advantage of new amp technology that made it practical to add a true woofer to it in a then very compact size for a 'full-range' speaker [AR-1].

Wasn't long before a super tweeter was added and quickly this type speaker was redone as a true three way that cost < just the 755!

In short, an 8" co-ax XO'd at < ~250 Hz [beginning of the analog telephone BW] to a reasonably wide BW woofer makes the most sense to me in a typical HIFI/HT app.
 
Could someone please refresh my memory and tell me what are the adverse side effects of big coaxial speakers and why "small = good"?
I mean the Great Plains Audio one is 16"...

Also I've began drawing a translam speaker for a 12" Celestion FTX1225 (I've found a par for an unbeatable price so...) and since I can CNC the whole thing I will be doing a rounded front baffle akin to the KEF LS50 but the question is how flush should I flush mount the speaker? Should I just make the rim of it flush or should I do something more advanced like pic related?
 

Attachments

  • DSC05145.jpg
    DSC05145.jpg
    332.6 KB · Views: 245
frugal-phile™
Joined 2001
Paid Member
Big drivers have trouble doing higher frequencies. And typically poor dispersion.

When i wa sdoing PA, i didn’t want to use the 15s above 350 Hz.

Large tends to bring higher efficieny, but a big coax has trouble reaching high enuff to meet the horn and one ends up with a hole in the crtiical midrange.

Now if you could get the horn tweeter down to 500 Hz, you might have a chance.

For instance of the classic 10, 12, 15” Tannoy coaxes the 10 is the one i like bass. But peopel tend towards the big ones to get “more” bass (most Tannoy boxes i have seen try too hard to get bass extntion the drivers really can’t do) so that is just anothe compromise. More bass (at a quality sacrifice) and a bigger hole in the upper midrange.anslam is

And i will comment that i thing translam is hugely wasteful, its only asset a brute force method to get a box with an unusual shape.

dave

dave
 
frugal-phile™
Joined 2001
Paid Member
To use translam to get as stiff as walls using the material in the direction it was engineered to be used means that typically a translam requires something like 2x the wall thickness. Another waste.

It is a brute force technique that does what it does but it is not elegant. But every loudspeaker design has to make many compromises.

dave
 
To me a large coax diy project is the perfect compromise.
It’s just very musical and the way to get there is very effective.

It doesn’t get easier to make it work; simple two way, high power, direct large sound, efficient easy load, easy to replace/upgrade, easy place, a lot for the money assuming you find a way with the crossover, usually the coax vendor have suggestions.

A large coax has bass, body, presence, and it has highs. It may not have deep powerful bass, crystal clear flat midrange or the highest highs so I totally understand why audiophiles avoid it, but for the low end diy it’s really something that gives a lot of value especially if you listen to music that usually works best in a club environment.

I’ve had so many small bookshelf’s+sub and 2,5 way slim towers that never really gave me any musical enjoyment like live do, but recent projects with coax gave that live feel into my home and I couldn’t be happier. I guess any PA would do the same though but why struggle with big horns when you can avoid it.
Of course 3-way have a much higher potential but the complexity and price I’m not sure it’s worth it at home. In a club yes.

Let me know how that Celestion works out for you.
Where did you find in stock and how much did you pay?
 
Last edited: