Tannoy Drivers in a JBL C34 Folded horn?

[seanrr]

I noticed that somebody is selling two JBL C34 Folded horn cabinets on my local CL. Has anybody tried putting Tannoy drivers in this particular cabinet? I think traditionally, this cabinet used a 15" JBL woofer and a horn, but I was thinking it might approximate the Tannoy GRF if the hole for the horn was covered. I only have 12" and 10" Tannoy dual concentric drivers. Might these work in the C34 if I used a baffle converter? Or would a 15" Tannoy driver work in these? Or are these really crafted for their original purpose and shouldn't be used with dual concentric drivers? I only ask because I have always wanted to hear a Tannoy using a folded horn cabinet since some say this sounds very nice.

 

[seanrr]

No thoughts?

 

[Tom Brennan]

Tannoy used their drivers in rear loaded horns so the notion isn’t an unreasonable one. I think rear loaded horns are more forgiving by their nature and more likely to work well with drivers others than they were designed for than front loaded horns and vented boxes are. Be aware that rear loaded horns sometimes give a response with the horn loaded lower bass elevated in level compared to the direct radiating upper bass and midrange. which might be subjectively agreeable. Yeah, I’d give it a shot, especially if the cabinets are reasonably priced.

You know, there are zillions of utility rear loaded horn cabinets out there that were used in sound reinforcement; JBLs as well as others, many of which are clones of the JBLs. They are often cheap and available.

 

[seanrr]

Be aware that rear loaded horns sometimes give a response with the horn loaded lower bass elevated in level compared to the direct radiating upper bass and midrange. which might be subjectively agreeable

I have read that. Some people say that this amounts to sucking out the midrange, which would be a pity with Tannoys. Yet, as you say, Tannoy itself created the GRF for their speakers, and some people suggest it is one of their best. Maybe the person selling them would let me try it....

 

[seanrr]

Would using a cabinet like this increase the sensitivity of the speaker markedly? I heard that it could raise as much as 5 db, which might allow me to use a 2A3 amp quite comfortably with my Tannoy 15" drivers.

 

[Tom Brennan]

The overall sensitivity of the driver will be the unaffected. The cabinet will increase the sensitivity only in the frequency range which is loaded by the horn—below 150 hz or so.

 

[jsg1974]

i would try the 12" in these , not sure these are big enough for the Tannoy 15".
there is an interesting article about all this in tnt-audio you might want to read.
but then again you can always try 15.

 

[Pio1980]

I noticed that somebody is selling two JBL C34 Folded horn cabinets on my local CL. Has anybody tried putting Tannoy drivers in this particular cabinet? I think traditionally, this cabinet used a 15" JBL woofer and a horn, but I was thinking it might approximate the Tannoy GRF if the hole for the horn was covered. I only have 12" and 10" Tannoy dual concentric drivers. Might these work in the C34 if I used a baffle converter? Or would a 15" Tannoy driver work in these? Or are these really crafted for their original purpose and shouldn't be used with dual concentric drivers? I only ask because I have always wanted to hear a Tannoy using a folded horn cabinet since some say this sounds very nice.

It just seem a misapplication and a waste of two good drivers to me, meant to be two-way wide-range direct radiators.

 

[pete1729]

The overall sensitivity of the driver will be the unaffected. The cabinet will increase the sensitivity only in the frequency range which is loaded by the horn—below 150 hz or so.

In my feverish research on back loaded horns the last words I read cautioned about wave cancelation at roughly 100hz.

 

[GordonW]

It just seem a misapplication and a waste of two good drivers to me, meant to be two-way wide-range direct radiators.

That would have been my thought, years ago- until a friend of mine DID it with some Tannoy Red 10s in a pair of JBL C34 cabinets I gave to him.

Holy crap, that sounded GREAT. The bass reinforcement of the C34 cabinet EXACTLY made up for the normal lack of low-end on the Red 10s.

He's still got them, over 10 years later. He's had other gear come and go, but NOT these.

Regards,
Gordon.

 

[Pio1980]

That would have been my thought, years ago- until a friend of mine DID it with some Tannoy Red 10s in a pair of JBL C34 cabinets I gave to him.

Holy crap, that sounded GREAT. The bass reinforcement of the C34 cabinet EXACTLY made up for the normal lack of low-end on the Red 10s.

He's still got them, over 10 years later. He's had other gear come and go, but NOT these.

Regards,
Gordon.

What about mids and top?

 

[GordonW]

What about mids and top?

The Tannoy Reds are dual concentric full-range drivers, with their own crossovers. He just installed the whole works into the C34s.

The overall balance was very good.

Regards,
Gordon.

 

[VintTannoy]

I have the Tannoy Gold 15 GRFs and before acquiring the GRFs I was planning to build the Tannoy GRF's with Gold 12". I had the plans and was looking for a woodworker locally to commission the build. What I learned from researching on the build is that the Tannoy GRF or back loaded design has to be precise and dialed in. There was this guy from Europe who documented his GRF build on his blog and I closely followed his build.. he completed his build except it looks like even though he tried to stay true to the original GRF design, his special build speakers did not end up sounding right.. so he had to convert his GRF build into a port/reflex build. So, I gave up the idea of the build and when a pair of GRFs came up, I bought them. I can attest that the bass on the back loaded GRF's is the best I have heard and I have heard many Tannoys.
So I would advice to pay heed to t/s measurements and be prepared to make adjustments if you go the Tannoys in the JBL cabs. Good luck!

MY GRF's: