Flattest response between 2000hz - 20 000hz

[Niklas Nord]

I need a horn driver and horn that can provide the flattest response possible between 2000hz and 20 000hz.

Where do I look, JBL or TAD or something else?

Maybe the horn could be tractrix -shaped?

["Duke" Spinner]

well ....

why is Flat Response your most important criteria ..???

[Niklas Nord]

offcourse all other tings is of most interest. And offcourse flat response can be achieved with the x-over !

[Cyclotronguy]

Seen here before,

In room response (3-4 meter) of Altec 511B with TAD 2001 second order crossover.

[Robh3606]

Well all compression drivers fall off above their mass break point at 6db per octave so they all need compensation for flat response. You can do it with the horn a crossover or a combination of both. They are only flat over a limited range. There are a couple of roads depending on the horn type used for flatest response. From playing around with the 2307, 2344, 2373 I can get them all flat from say 2K-12K maybe a bit more but the 1" drivers won't get you out to 20K. If the 1" won't the 2" won't either. You are not going to get that flat curve out to 20K without adding a 2405 as an example but then you have ripples in the response above and below the crossover point. Another issue is besides the flat on axis response they all have different DI characteristics you can easilly hear in a normal room as these sum with the on axis response. I would be more concerned about the horn type used than flat response. You can get them all to measure real close but they simply sound different. I would go for the horn/sound charateristics you like best and work to get them as flat as I could. Don't go by flat as the most important characteristic. Tractrix sounds very nice from what I have heard listenning to the Titans. They use a tractrix mid with a Fane tweeter up top to get out above 10K.

4344 on axis 2 meters 1/3 octave 1 second gate averaged with 2416 2307/H94 Second is 2344 with 2416 same conditions. Between 1K and 10K very similar but sound noticeably different. You can see the roll off in the 1" drivers with the 2344 combo.

Rob

[Zilch]

Mr. Widget has published an incredibly flat horn/driver combination here; I recall it was a TAD driver.

BUT, as Robh points out, the desired sound distribution characteristic is by far the more important starting criterion for selection. On-axis response is only a portion of it....

[Mr. Widget]

I don't think you will find a horn driver combo that exhibits a flatter on axis response than this. The red plot is the TAD TD4003 driver mounted to TAD TH4003 horn. The blue plot is the same driver mounted to a cast resin clone of the horn that I have made. They are both about +/- 1.25dB between 600Hz and 12KHzwithout any EQ. They do roll off above 12KHz. I have recently received some newer examples of the TD4003 drivers and they seem to have a slightly more extended top end.

As for the importance of constant directivity, I believe it is a subject that is up for debate. These horns have tightly controlled directivity with a pattern of 30° by 80°. In my room with floor to ceiling drapes on the side walls I find the imaging to be exceptional. Additionally the sound only changes slightly as you move about the room.

Widget

[Niklas Nord]

Hello Friends !!
ok then, but is there no JBL -driver as flat as the TAD then?
The TAD 4003 seems to be great.

It´s only one problem, I would like to have this in a small enclosure.
Would it work with a little tractrix -like horn?

Si there anybody using any TAD´s with tractrix?

[Mr. Widget]

It is the horn and driver together that gives you the response curve. I have a friend that uses the TAD TD4003 on a Tractrix but the response is not the same. He still likes it a lot, but you may find that you prefer a different driver on a tractrix.

There is another catch. The TD4003 is difficult to get, I had to wait months, and they are extremely costly.


Widget

[Niklas Nord]

Hello
Aha, so the 4003 dont work so well on the tractrix then..
And if it´s not easy to get.. hmm..

I would like to squeese a horn in a small box, it´s only 26cm wide..

[Zilch]

10"?

For $38, try the JBL OASR horn:

http://audioheritage.org/vbulletin/s...t=1915&p=16719

[Mr. Widget]

Aha, so the 4003 dont work so well on the tractrix then..

I didn't say that... I said that you won't get the response I posted. Here is a photo of the TD4003 mounted to a small tractrix. It is the small horn near the tweeter. This is an amazing system, but due to the design of tractrix horns, you will need a tweeter.


..or you can take Zilch's recommendation and use the OASR... just be aware that you will need some form of EQ, with all of the gains and losses associated with them.


Widget

[yggdrasil]

I tried these data on a tractrix calculator. Guess what? No usable echo. Horn length < 1 cm. When using Fc = 1000Hz -> Horn length 2-3 cm.


The Tractrix formula gives short horns, especially when the driver size increases. Using a 1" driver gives more sense on a tractrix horn from 2k.


http://melhuish.org/audio/tractrixcalc.html

[whgeiger]

I need a horn driver and horn that can provide the flattest response possible between 2000hz and 20 000hz.

Where do I look, JBL or TAD or something else?

Maybe the horn could be tractrix -shaped?

NN,

Some notes follow:

1) For this spectrum, the TAD 2001 or TAD 2002 would be better choices. At 1000 Hz (octave below high pass filter [f6]) and above, use of a 4" diaphragm (TD-4001,2,3) driver is contraindicated unless a PA venue is anticipated.

2) For any tweeter/horn combination, while flat (approximately) on axis response is possible, power response is not. As frequency increases, power response will decline while the energy that remains becomes more focused into a beam. For best results, power and on axis response should both decline equally. Then when the required equalization is applied, signal beaming will not be emphasized.

3) If a circular section horn is to be used, then an exponential neck with slope angle matching that of the driver throat opening is preferred. Finish this off with a tractrix bell. This may be accomplished by equating formula derivatives. If you match the tractrix flare tangent directly to that at the driver opening then only one tractrix horn is possible.

Regards,

WHG

[Mr. Widget]

For this spectrum, the TAD 2001 or TAD 2002 would be better choices.

I would agree. If you do not need or want a lower crossover point, then the 2001 or 2002 will most likely be the drivers of choice if cost is no object. They are bargains compared to the 4003, but are still on the pricey end. Actually, TAD suggests that the 2002 is good above 400Hz, but I kind of wonder about that.

For best results, power and on axis response should both decline equally. Then when the required equalization is applied, signal beaming will not be emphasized.

This is currently JBL's approach with horns. In theory it certainly makes sense, but in my practical exploration the offense of equalization is far worse than a less than ideal power response. There are many successful speakers on the market that also go against this theoretical ideal. (Most all dome based designs have a narrowing of power response with increase in frequency, and there are many that are quite successful.) As I mentioned above in post #7, I do believe this is and area open for debate.

Widget