TH Criteria ?

[Zero D]

Hi all TH fans

Just wondering what you consider the most important specifications a driver requires for a successful TH design ? Apart from Xmax/SPL@1W/Power/Sd

1 - High or low Qm

2 - High or low Qe

3 - Below or above overall Qts of .3

4 - Vas Below or above 300L

Anything else ?

TIA

[Rademakers]

1 - Most driver seem to be in the ~4 - 8 range, not a necessity afaik.

2/3 - Qes/ Qts are ussually quite close, especially in the lower range. Lower Qes drivers often require differerent segment, compression ratio and driver positioning then higher Qes drivers. Traditional (as in Danley's typical) tapped horns are ussually low Qts drivers (lower then 0.3)

4 - Vas is driver diameter related 300 L is average for an 18" PA driver, 200 L average for a 15" PA driver, etc. Overall low(er) Vas is good.

Vas can also be related to Qes in designing a tapped horn. Traditional tapped horns seem to favor both low Vas and Qes. Up to a point higher Vas could be counteracted by very low Qes and vice versa.

5 - Fs = 1.414 x Fc

Taking 2/3 - 4 - 5 in mind (Fs, Qts, Vas) I personally would discard "stated sensitivty" as an important specification.

Danley also stated Mmd/Mms iirc, which would imply high Xmax and large VC.

Best regards Johan

[Zero D]

@ Rademakers

Hi & thanks for responding

I'm surprised others havn't been able to contribute with their data ? I thought there were quite a number of members on here who are more than just a little bit interested in TH designs etc !

[weltersys]

Originally Posted by Zero D

@ Rademakers

Hi & thanks for responding

I'm surprised others havn't been able to contribute with their data ? I thought there were quite a number of members on here who are more than just a little bit interested in TH designs etc !

High Bl is needed.

A well designed TH can be 6 dB more sensitive than a BR, but the load on the cone is also way more.
A very stiff cone is needed to keep distortion reasonable at high power, Hornresp will show light cones with high Bl to be quite high in sensitivity, but when pushed hard the driver will sound distressed before Xmax is reached.

That said, it seems there are many TH builders that don't mind that sound.

Art Welter

[Zero D]

Hi, thanks for posting

Originally Posted by weltersys

High Bl is needed.

I guess that may be only be a prerequisite for designs with high compression ratios in the throat ?

Hornresp will show light cones with high Bl to be quite high in sensitivity, but when pushed hard the driver will sound distressed before Xmax is reached

.

So no free lunch then

That said, it seems there are many TH builders that don't mind that sound.

Maybe they havn't admitted it, as i don't recall anyone mentioning it

[Spuddy]

Originally Posted by Zero D

Maybe they havn't admitted it, as i don't recall anyone mentioning it

Maybe they can't tell what's happening amid the chaos

I've had my Kraken TH up and running for a week now, and I have no idea how loud it gets or how clean it is, because every time I try upping the volume at 16-18hz my house feels like it's collapsing and I wimp out! Not even kind of exagerating

[weltersys]

Originally Posted by Zero D

Hi, thanks for posting
I guess that may be only be a prerequisite for designs with high compression ratios in the throat ?

Perhaps, I have not played extensively with low Bl and low compression, but putting a whimpy magnet 10" in a 2.5/1 ratio TH resulted in a response curve that looked like an upside down "V", the worst response I'd ever seen, while in a ported box of a similar size, the same speaker had reasonable response.

The driver has to push and pull a long column of air in two directions in a TH, that takes a real motor.

[Spuddy]

Originally Posted by weltersys

Perhaps, I have not played extensively with low Bl and low compression, but putting a whimpy magnet 10" in a 2.5/1 ratio TH resulted in a response curve that looked like an upside down "V", the worst response I'd ever seen, while in a ported box of a similar size, the same speaker had reasonable response.

The driver has to push and pull a long column of air in two directions in a TH, that takes a real motor.

Sorry if I'm somewhat out of my league here, but would this be the reason some larger horns utilize two drivers set up in a push/pull configuration? If yes, then is that something worth taking into consideration for the criteria of this thread?

[Zero D]

Originally Posted by Spuddy

Maybe they can't tell what's happening amid the chaos

I've had my Kraken TH up and running for a week now, and I have no idea how loud it gets or how clean it is, because every time I try upping the volume at 16-18hz my house feels like it's collapsing and I wimp out! Not even kind of exagerating

Sounds good Is that with movies, and/or music ?

Sorry if I'm somewhat out of my league here, but would this be the reason some larger horns utilize two drivers set up in a push/pull configuration? If yes, then is that something worth taking into consideration for the criteria of this thread?

Well that would reduce f2 distortion But as in other designs, f2D is often viewed/heard as a bonus !

Originally Posted by weltersys

Perhaps, I have not played extensively with low Bl and low compression, but putting a whimpy magnet 10" in a 2.5/1 ratio TH resulted in a response curve that looked like an upside down "V", the worst response I'd ever seen, while in a ported box of a similar size, the same speaker had reasonable response.

Ooh err

The driver has to push and pull a long column of air in two directions in a TH, that takes a real motor.

Points taken Thanks

[bjorno]

Originally Posted by Zero D

..I'm surprised others havn't been able to contribute with their data ? I thought there were quite a number of members on here who are more than just a little bit interested in TH designs etc !..

Zero D,

From post#1 I generated a bunch of fictive drivers for you to be ..DIY.. simulated in HR and evaluated for TH suitability .
Besides avoiding the lower row of drivers (Too low cone weights) Which one would be your driver choice?

b