Blending compression drivers?

[weltersys]

I have seen people claim the same and people that claim a properly designed manifold doesn't negatively impact performance.

There are many unsubstantiated claims.

Does anyone have experience with manifolds or information that is not pure heresay?

I have used and heard a variety of manifolds, the best being those developed by David Gunness for the Electro-Voice MT (Manifold Technology) series of cabinets.
I returned eight of those EV MTA-22 adapters to the factory after evaluation.

Using MT, SPL (sound pressure level) can be increased, but fidelity is reduced, as can clearly be seen in Pat Brown's response measurements using the EV MTA-22"

https://www.prosoundtraining.com/2010/05/26/manifold-drivers/

An ideal dual manifold would result in a +6dB response identical to the driver's response, in actuality, the response is more like +3dB (at best..), and less smooth.
At high SPL, air becomes non-linear, manifolding drivers through a single throat increase distortion considerably.

Note that Dave Gunness does not use any similar high frequency combining manifolds in his current Fulcrum Acoustic products.

My idea is to try it with two different titanium drivers combined with 2 different phenolic ones.........if it is not an obviously flawed idea. P audio pc-70 4x1" to 2"

The P Audio PC-70 is little more than a plumbing fixture.
It's summed response is worse than the EV MT parabolic reflector type manifolds.

Combining different driver types on the same manifold make defects that could individually be addressed impossible in the aggregate.

To put it simply, rather than getting the "best of two worlds" you get the worst of both, poor frequency response, increased ringing time, additional harmonic distortion and less output.

That said, those attributes may be desirable for sound production (as in guitar amps) but not for sound reproduction.

Art

 

[ErikNils]

That said, those attributes may be desirable for sound production (as in guitar amps) but not for sound reproduction.

I get the picture. I did experiment with 10 inch guitar drivers once and my feeling was they are closer to instruments than transducers....

I think I will leave horns to the pro's. I have too little experience with them. They seem great for filling stadiums. I know they can sound great in a home but there you need very careful horn flair choices and giant round overs (negative flair) to avoid hearing the horn.

I will probably go for open baffle 250cm tall line arrays with 120 x Chinese clone of the Dayton pt6mini planar tweeter (back to back out of phase, 30 per face)

 

[ErikNils]

An ideal dual manifold would result in a +6dB response identical to the driver's response, in actuality, the response is more like +3dB (at best..), and less smooth.
At high SPL, air becomes non-linear, manifolding drivers through a single throat increase distortion considerably.

I like KISS (keep it simple stupid). Getting into manifolds seems counter productive. Thanks for your help!

 

[GM]

......giant round overs (negative flair) to avoid hearing the horn.

Not if you damp the terminus with something as simple as wrapping a soft towel around it or adding a foam baffle.

 

[BHTX]

What about this?...
https://josephcrowe.com/blogs/news/2094

"Dual SB Audience 65CDN-T with Y-adapter and custom rear chambers"

 

[Zoran]

That Is OK
BUT it it is not like in the photo with guitar, double big horn and one bass driver...
.
Main problem with compression drivers is attenuation. Transformer-choke type of att only working.
The SPL is huge even with one HF comp driver in horn. It looks nice but it is simply not realistic...
.
And ususaly one comp drv is 10-15 db higher SPL level than one bass driver. L-pad and other Resistor attenuation ruining the sound quality a lot. L-pad is the worse. Bridged T net is the best from R types.
Best sounding is transformer core choke with taps for att.
(Preferably Walter Hahneman balanced crossover concept.)
.
It is not the final solution for adding the bass drivers because we will have aprox +6db for 4 x bass drivers.
But that is also significant step forward to matchinf the very high SPL og comp horn segment...
And that is upper level of multiply bass drivers because for adding 4 more for 8 pieces, the gain is just 9db...
So optimum is 4 bas drivers.
.
Active way to match the levels with different power amplifiers is OK but for 10db dif. power shuld be 1:10 also...
So for 10W compresion horn driver amp, 100W of output energy is needed... 🙁 And -db is ususaly more.
With 2 x horn drivers is +3db more than with single
.
To conclude: from my experience the level match is crucial. That is the first step. So 4 bass drivers and then Choke with transformer core attenuation.
Then crossover...
.
cheers

 

[Speedysteve7]

I have a hard time believing combined Comp Driver HF will sound as good as a single one on the right horn for near field Hifi use unless very cleverly designed and executed.

I've not head the Danley HF combiner horn solutions.. In their intended use (massive arena and fields) I'm sure they work just fine. Done for SPL gains.

Combining lower frequencies certainly works. I have 4 MF drivers (~325Hz to ~1000Hz) combined in a MEH no problem.

Having tried a BMS comp driver and had to EQ it more than an expensive driver I prefer to use, for Hifi I'm in the invest in a best drivers you can camp.

It came up earlier here about nearfield MEH listening - I listen to my SH50 style MEH horns for Hifi near field, ~4m distance and they are amazing!
So much so I dismantled my individual 3 horns + Tweeter rig + TH bass (I had evolved over 10 years), and run the SH50s with the THs now - couldn't be happier.

 

[Zoran]

This is a good concept network for compression horns. I found in listening terms, better than others.
Ofcourse not this high order filter nets...
It is enough 2 to 3 order types.
cheers.
https://patentimages.storage.googleapis.com/19/22/e9/70aec31cee08ee/US1674683.pdf
I know that sounds crazy, but the concept is from 1926, decades away from linkwitz transfprm...