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-   -   Tapped or front loaded horn? (http://www.diyaudio.com/forums/subwoofers/225042-tapped-front-loaded-horn.html)

Omholt 5th December 2012 12:58 PM

Tapped or front loaded horn?
 
1 Attachment(s)
What are the advantages and disadvantes with tapped horn vs front loaded horn?

I'm interested in a high quality horn subwoofer. Initially to use in a home theater but also get the chance to try it out in a two channel setup where I also need a subwoofer solution in near future. Horn is tempting due to high output and low distortion.

The ideal bandwidth would be 18-120 Hz (I know, probably too wide) and my minimum requirement would be 23-85 Hz. The Danley DTS 20 would fit the bill, but unfortunately isn't sold as kit.
http://www.diyaudio.com/forums/attac...1&d=1354715715

P.S.
I don't have the skills to do simulate accurately, so I'm open for someone to contact me with designs that can be passed on to a local carpenter. Preferable someone with very good experience and even better if some who can use more advanced math (Leach's math?) then Hornresp. I can afford high quality driver(s).

SemperFi 5th December 2012 01:03 PM

The math used in Hornresp isn't advanced enough?

Omholt 5th December 2012 02:51 PM

Quote:

Originally Posted by SemperFi (Post 3271421)
The math used in Hornresp isn't advanced enough?

I've heard there are more advanced calculations then can yield a better result and I believe that's why the Danley tapped horns are able to cover a wider area, but I could be wrong.

wrager 5th December 2012 07:18 PM

The DTS-10 is roughly 15-100. The bigger ones like the 212 are 30 to 200 ish.

more10 5th December 2012 08:44 PM

Tapped horns will have a significant phase shift at 3 x base frequency, i.e. high group delay. I have built a front loaded "horn", see JBL 2226H 30 hz "horn" i built, which has less problems with group delay, but is still bandwidht limited. If you want more bandwidth you need to make a proper front loaded horn.

Omholt 7th December 2012 05:21 PM

Quote:

Originally Posted by wrager (Post 3271890)
The DTS-10 is roughly 15-100. The bigger ones like the 212 are 30 to 200 ish.

The DTS-10 seems to have peaks and resonances above 55 Hz. See below and and compare with Danley's spec sheet as well. I also don't need response down to 10 Hz.
Data-Bass
Spec Sheets | Danley Sound Labs | Danley Sound Labs, Inc.

Omholt 7th December 2012 05:24 PM

Quote:

Originally Posted by more10 (Post 3272000)
Tapped horns will have a significant phase shift at 3 x base frequency, i.e. high group delay. I have built a front loaded "horn", see JBL 2226H 30 hz "horn" i built, which has less problems with group delay, but is still bandwidht limited. If you want more bandwidth you need to make a proper front loaded horn.

Yes, I've heard about the phase shift. Needs to be crossed over below.

Is it correct that a front loaded horn will not have the same output as the tapped horn at the lowest frequencies?

And it seems likea front loaded horn becomes wider then a tapped horn. Correct? I need to make sure I can pass it through my doors when moving it between rooms.....

weltersys 7th December 2012 06:30 PM

Quote:

Originally Posted by Omholt (Post 3274956)
Yes, I've heard about the phase shift. Needs to be crossed over below.

Is it correct that a front loaded horn will not have the same output as the tapped horn at the lowest frequencies?

And it seems likea front loaded horn becomes wider then a tapped horn. Correct? I need to make sure I can pass it through my doors when moving it between rooms.....

The phase shift exhibited in the pass band of a FLH and a TH are not all that different in the pass band.
Both will require the top cabinets to be delayed by the approximate path length to be time and phase aligned at the acoustic crossover frequency.
Unless the FLH is very large, it will have a falling response to the low cutoff.
A FLH will require a larger mouth and overall volume to go as low as a TH.

A FLH can be designed with the room corner as part of the horn, which can save a lot of area.
That said, the FLH mouth does not have to be square, an average house door sized mouth can go down to 20 Hz.

Hornresp is adequate for either a FLH or a TH design, the room will have far more affect than any differences between the simulation and the actual build.

Josh Ricci's Gjallerhorn comes very close to what you are looking for in terms of FR.

Djim 7th December 2012 09:04 PM

Hi All,

At full wavelength the cone in the 'tap' of a TH moves in opposite direction (out of phase) compared to cone in the throat. This will cause a peak in group delay and a 'ring' in the waterfall plot that is audible. Front loaded horns don’t have such issue because there is only one sound source in the horn.

Omholt 9th December 2012 07:51 AM

Quote:

Originally Posted by weltersys (Post 3275024)
The phase shift exhibited in the pass band of a FLH and a TH are not all that different in the pass band.
Both will require the top cabinets to be delayed by the approximate path length to be time and phase aligned at the acoustic crossover frequency.
Unless the FLH is very large, it will have a falling response to the low cutoff.
A FLH will require a larger mouth and overall volume to go as low as a TH.

A FLH can be designed with the room corner as part of the horn, which can save a lot of area.
That said, the FLH mouth does not have to be square, an average house door sized mouth can go down to 20 Hz.

Hornresp is adequate for either a FLH or a TH design, the room will have far more affect than any differences between the simulation and the actual build.

Josh Ricci's Gjallerhorn comes very close to what you are looking for in terms of FR.

From what I know also the Danley TH has the phase shift above 100 Hz. I don't think this is the case with Bill's FLH (Tuba HT). Are you sure this is correct?

If the FLH can be crosses over higher, it would make it an interesting canditate in my two channel setup. There I need something that can give me the flexilibility of crossing over quite high (200 Hz area). My inital thought there was either build two large bass reflex subs or sealed towers with multiple drivers.

The Gjallarhorn does have som peaks and resonances. Seems to be the case with all TH designs. Does this happen with FLH as well? I haven't seen any anechoic waterfalls of FLH.


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