TAD TM-1201 horn loading

[virious]

Hi

I am thinking of horn loading my set of TAD TM-1201s in a front horn. Probably in a 150 Hz horn and then cross at about 250-300Hz.

Has anyone tried this or would it be better just to use it as a direct radiator?

Are there any commercial horns in that size that suits the TM-1201?

Many thanks,
Jeppe

[whgeiger]

Originally Posted by virious

Hi

I am thinking of horn loading my set of TAD TM-1201s in a front horn. Probably in a 150 Hz horn and then cross at about 250-300Hz.

Has anyone tried this or would it be better just to use it as a direct radiator?

Are there any commercial horns in that size that suits the TM-1201?

Many thanks,
Jeppe

A properly designed horn will provide a decade of usable bandwidth.

You will need a horn of comparable dimensions to provide loading down to a 2 meter wave length.

The primary purpose of such a horn, is to cover the speech range (200-2000 Hz) without bifurcation

There are very few manufacturers that provide, medium format, speech-range horns. Of these the following are notable:

Funktion One (Tony Andrews)
FUNKTION-ONE : OFFICIAL WEBSITE

Community Light & Sound (Bruce Howze)
Community Professional Loudspeakers

This JBL technical tech note may be of some help.
http://www.jblpro.com/catalog/suppor...pe=3&docid=201

Only in a listening space, a magnitude larger, will use of such a horn be beneficial.

Regards,

WHG

[limono]

You will find opinions here based on horn resp sims ,that TM 1201 is not really suitable for horn loading. Do a search on forums.

[virious]

Sorry for the late reply!

whgeiger: Could you post a direct link to the horn you think you be suitable as i'm not able to find it

limono: Could you also provide a link? I think i have read just about anything about the 1201, but not that its best used as a direct radiator.

Many thanks for your replys,
Jeppe

[whgeiger]

If you want a speech range horn, to match the TD-1201 you will have to design it yourself.
This would be a non-trivial, although a possible exercise. I have already given you guidelines for doing that.
Parameters for this driver follow:
Nominal Impedance 8 Ohm.
Lowest Resonance Frequency (Fo)52 Hz.
Frequency Range 150-4500 Hz.
Rated Input Power 150 W.
Maximum Input Power 300 W.
Sound Pressure Level 100 dB/W (1m).
Total Magnetic Flux 324.000 Mx.
Magnetic Flux Density 14.500 G.
Recommended Bandpass Filter 200 - 3.000 Hz.
Recommended EnclosureOver 11 liter.
Effective Piston Diameter 260,0 mm.
Baffle Opening 276,0 mm.
Mounting Dimensions 293,0 mm.
Weight 11 kg.
Dimensions (diameter x depth) 318 x 110 mm.
Theile-Small Parameters
sd - Piston Area 0,0531 Sq M.
Revc - DV Voice Coil Resistance 5 Ohm.
Levc - Voice Coil Inductance 1kHz (mH) 0,68.
BL - Flux Density (TM) 26,0.
Vas - Equivalent Acoustic Volume (Liter) 63 liter.
Cms - Mechanical Suspension Compliance (x 10-4 m/N) 1561.
Mms - Mechanical Mass of Cone and Free Air Load6 g.
Mmd5 g.
Fs - Free Air Resonance Frequency 52 Hz.
Qms - Mechanical Q Factor1,43.
Qes - Electrical Q Factor0,15.
Qts - Total Q factor0,14.
Xmax - Max Linear Peak Excursion (O-P)2,5 mm.
Pmax - RMS Thermal power Limit300 W.
no - Relative Efficiency5,54 %.
Vd (cm²)1,33.
Max. Excursion Before Damage (P-P)22,
Run some simulations using Horn-Response to see where it takes you.
Horn throat Sd/2, length > c/(4*Fc), Mouth perimeter, = approx. c/Fc
Otherwise a simple sealed enclosure, with low-end equalization will do, unless your listening space is huge. Sensitivity of this driver is high.
As this is a low-Q driver, with limited xmax, c/o at >200 Hz.
Regards,
WHG

P.S.

Here's the SPL plot from Horn-Response (McBean) with the TAD TM-1201 on a cosh horn.

[CLS]

Originally Posted by whgeiger

If you want a speech range horn, to match the TD-1201 you will have to design it yourself.
....

Mms - Mechanical Mass of Cone and Free Air Load 6 g.
Mmd 5 g.

The above, 5 or 6g, is wrong. It's from published datasheet I know, but it's wrong.

Times ten is more like it. And you'll have a much more declined FR.

[whgeiger]

Originally Posted by CLS

The above, 5 or 6g, is wrong. It's from published datasheet I know, but it's wrong.

Times ten is more like it. And you'll have a much more declined FR.

Qts and Fs are correct so the the typo has no effect!

Regards,

WHG

[CLS]

Have you built (of found) such a horn for this driver and given the combo a listen (or measure)?

Guess what? I have

[CLS]

And that's a big beautiful failure. The biggest and most beautiful I have had.

[revintage]

You will find opinions here based on horn resp sims ,that TM 1201 is not really suitable for horn loading. Do a search on forums

Limono, you are so right. It wasn´t so long ago we discussed the subject here. This driver is not suited for horn use.