What kind of speakers do I have?

[robber222]

I have a pair of Odeon Rigolettos aka Einstein Rigolettos. They are categorized as TQWT, but I've not been able to find any others online that have the same characteristics. They have Audax tweeters and modified Fostex FE164. But... the bottoms are open, so the entire bottom of the speaker acts as a port I suppose. They stand on wood plinths. Any idea what specific sub-category of TQWT they are? Thanks for any help.

[planet10]

Sounds like a TQWT. You can typically get better/smoother bass by mass loading a TQWT.

dave

[robber222]

I know that it's a TQWT.... but I thought there were different "species" of TQWT. I don't think I could mass load these since they have no bottoms. The bottoms are open/hollow.

[planet10]

By TQWT i mean Classic TQWT, a taperd pipe with the driver mounted ~1/3 distance along from the (smaller) closed end. These typically have significant ripple in the bass, althou corner loading can help (as in the BIB)

To mass load them you could add a bottom, or you could just shorten the height of the bottom off its plinth. The original MJK ML-TQWT design was for FE164 so that is a reference you should read.

dave

[Svein_B]

I believe the open ended TQWT is often referred to as a Voigt-pipe.

It also appears to be similar to the iBiB (Inverted BIB) discussed on this forum.

Depending on the internal geometry it could also be a kind of horn (or really horn mouthed BVR), as in the British Impulse series of speakers.

SveinB

[robber222]

OK... please forgive my ignorance.... I guess I just don't understand the definition of "mass loading". I thought you meant loading with sand or gravel. As far as the internal structure, it's typical TQWT. There's an MDF board that starts at the front bottom and is slanted backward all the up to just below the Fostex driver. If I was to add a bottom to the cabinet, I would still have to port it, correct? And a front port would be in the way of the internal "slanted board".... so it would have to be in the back of the cabinet.

[chrisb]

Originally Posted by robber222

OK... please forgive my ignorance.... I guess I just don't understand the definition of "mass loading". I thought you meant loading with sand or gravel. As far as the internal structure, it's typical TQWT. There's an MDF board that starts at the front bottom and is slanted backward all the up to just below the Fostex driver. If I was to add a bottom to the cabinet, I would still have to port it, correct? And a front port would be in the way of the internal "slanted board".... so it would have to be in the back of the cabinet.

From what I can make of the Manufacturer's site and your description, this would more likely be classified in today's jargon as a chamberless folded tapped back loaded horn - so Svein is probably close with his guess at inverted BIB

Provided you don't mind a bit of fiddling about with reversible mods, it couldn't hurt to reduce the height to the floor, play with levels of stuffing, and/or fill the opening with a wood plate including port. The trick of course to the latter is determining the port dimensions and damping by methods other than iterative trial and error - which is where the math that Dave referred to as described on MJK's site is invaluable.

[rjbond3rd]

It is definitely not a TQWT!

It is a traditional BLH with a chamber. There is a chamber, and then two conical expansions approximating an exponential expansion. I have a set in the garage.

Take off the FE164, reach your hand inside. You'll see a divider that slants -toward- the front of the cab. That forms the chamber. At the bottom of that divider, there is a little "shelf" and that forms the throat. The back of the divider forms the first expansion, which goes up. Then it turns 180 degrees and comes down to the terminus (which fires at the floor).

So three "sections" -- the first is the chamber, the second and third conicals approximate an exponential.

[planet10]

The port adds a restricton/mass to the pipe. It could fire out the bottom.

dave

[robber222]

Originally Posted by rjbond3rd

It is definitely not a TQWT!

It is a traditional BLH with a chamber. There is a chamber, and then two conical expansions approximating an exponential expansion. I have a set in the garage.

Take off the FE164, reach your hand inside. You'll see a divider that slants -toward- the front of the cab. That forms the chamber. At the bottom of that divider, there is a little "shelf" and that forms the throat. The back of the divider forms the first expansion, which goes up. Then it turns 180 degrees and comes down to the terminus (which fires at the floor).

So three "sections" -- the first is the chamber, the second and third conicals approximate an exponential.

I have also read posts that categorize them as BLH speakers. The only thing I can see when I turn the speakers on-end is a board which starts at the bottom front of the cabinet and slants backward. The board/divider ends rite around the magnet of the Fostex. I don't see a "shelf". The divider board just stops... no other turns or bends. The chamber created between the divider and the front of the speaker is stuffed... and the area behind the drivers is fully stuffed with damping material as well.