Horn loaded mid/bass cab (BD-Design)

by GC, Friday, March 04, 2005, 14:21 (4703 days ago)

I'm building a large system, last jears i spend on building and testing subwoofers and i build a proto type tractrix horn for the mids. Mid is driven by a ACR fe 103 s in a 300 Hz hoorn. At this moment i have a mono proto type set up wich includes a 200 liter closed subwoofer with 15" TC sounds driver, bandpass horn mid/bass with B&C 15PL40, the mid horn and seas excel 001 tweeter. I use the behringer DCX 2496 for filtering and some correction on the mid horn.

Most recent pic:
[img]http://groups.msn.com/_Secure/0RwDvApsUccgAtPpUmvsVlqkVVIXwqnMtQPZY3PVoL!O0i7EYa6XntYkyZhfwalJaXpZ9baIT6giyZMVgfbDyEPbrNqXVFuQ0xMfkz0VM*OA/DSC04411.JPG[/img]

The closed sub will be replaced bij a double 8" folded 30 Hz horn wich preforms even better then the TC sounds sub.

Preformance of this set up is verry good. I like some verry heavy bass and a nice kick and this set up gives wht i want, but i want to try some other things before i spend a lot of money on a stereo set up.
The bandpass horn is the first mid/bass cab is have used in this set up, i\m planning to build/design a new cab.
First i was thinking about the lascala, its a nice small cab and i have read some good words on it. But when i put the parameters in a simulation a 100 Hz hoorn. I want to go to 65 hz for a good inergration with the sub horn. I extended the horn, enlarged the mouth en reduced the back chamber to get down to 70 Hz.
[img]http://groups.msn.com/_Secure/0YADoAmMdZoqEsN40D0tXrs482s2HABNDmstH3nfZxcXjGWYmuhd3NwjQmOVIZqMu2dsUX!93s7KgPWMWgePHXiqVmNJ4ap!Da4W5xenFiCtjENHq2sTGFmTEjFUFMMXuDdb*smtdLIGCcmACTW96aQ/Sim%2015pl40%20lascala%20verlengt.JPG[/img]
Simulation is 1/4 space)

But i have some questions about the lascala, and midbass horn design. Depends the lascala on the large backcamber to to lift up output below the flare frekwentie?? I think a lager 60/70 Hz horn will preform much better then a small compromised horn like the lascala. How do you guys think about this?

At this moment i am thniking about a bigger cab based on the lascale, or a total new desing with a straigth 70 Hz horn. The straigth horn can get a big large.

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Horn loaded mid/bass cab

by GC, Sunday, March 06, 2005, 09:41 (4701 days ago) @ GC

Hi Michiel,

But i have some questions about the lascala, and midbass horn design.
Depends the lascala on the large backcamber to to lift up output below the
flare frekwentie?? I think a lager 60/70 Hz horn will preform much better
then a small compromised horn like the lascala. How do you guys think
about this?

A larger horn will go a bit deeper but is still limited due to its size.

Think of the wave length which is very long. You'll have to find a balance between sensitivity, the Q and the bandwidth. Less sensitive makes the bandwidth wider. Using a larger back chamber, a higher Q driver and a larger throat changes more than just making the flare different.

Ciao,

Bert

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Horn loaded mid/bass cab

by GC, Sunday, March 06, 2005, 23:40 (4701 days ago) @ GC

Thanks for your reply!

Now i'm thinking about 2 designs. First a straight horn with 80 cm length and a quite large front camber to get the benefits of a bandpasshorn.
Or a horn with 1 meter length folded like the lascala with a large backcamber...

I can design the horn with a relative small mouth wich will give less sensivity and a lower f3. In combination with a large back camber, will this give the lower f3?

How do you think about simulating horns like this?

I will build 1 or 2 proto types to compare them with my bandpass horn. After testing i will work out the cab wich give me the best result in de test. But i want to get as much as posible from the new proto types.
This is the driver i use: http://www.speakerstore.nl/view_new.php?l=nl&p=sp&spkID=116 Parameters look good for horn loading.

Do you have any sugestion for mee? Something i can worked out for a proto type?
The limiting factor is the depth of the cab, i dont want to go over 1 meter total. A straigth horn will be a little problem if the horn has to go down to 65 Hz. I think 75 Hz would be the max for the subhorn.

Also, what do you think about folded horns and a hf respone to 300 Hz?

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Horn loaded mid/bass cab

by GC, Monday, March 07, 2005, 22:32 (4700 days ago) @ GC

Hi Michiel,

I can design the horn with a relative small mouth wich will give less
sensivity and a lower f3. In combination with a large back camber, will
this give the lower f3?

A larger throat will widen the band width and a larger back chamber will give more sensitivity in the deeper bass. Leave the mouth at maximim and play with the throat and back chamber in your simulations.

How do you think about simulating horns like this?

Its a big help but it won't tell you how to build it which is responsible for the quality of the sound.

Do you have any sugestion for mee? Something i can worked out for a proto
type?

Peter van VennHel had a good design that played down from 50Hz up to 250Hz pretty well. You could ask him for the drawing (he's in the showroom).

Also, what do you think about folded horns and a hf respone to 300 Hz?

If build well then its okay with me, the only problem remaining is the timing...

Ciao,

Bert

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Horn loaded mid/bass cab

by GC, Tuesday, March 08, 2005, 00:01 (4700 days ago) @ GC

A larger throat will widen the band width and a larger back chamber will
give more sensitivity in the deeper bass. Leave the mouth at maximim and
play with the throat and back chamber in your simulations.

Thats is what i was thinking. The mouth can be someting like 50 * 70 cm, wich i think is a nice size for the front of a mid/bass horn. But enlarging the throat is limited with one 15" driver. A way to get a bigger throat is to use 2 15" drivers per side. With larger SD you dont have to make the horn longer for proper loading on the driver.

Its a big help but it won't tell you how to build it which is responsible
for the quality of the sound.

Correct. Thats way I build and test the proto types before i decide what to do for the final set up. But this time i want to come as close as posible to the best result. so i will take some more time for this project.

Peter van VennHel had a good design that played down from 50Hz up to 250Hz
pretty well. You could ask him for the drawing (he's in the showroom).

Thanks for the tip, i will contact him.

If build well then its okay with me, the only problem remaining is the
timing...

Do you mean a delay with timing?! Is use a DCX 2496 so i can set the delays on the difrent drivers.
Personaly i think a straigth horn will work better than a folded one, but i never did research on this.

My most recent idea was to build a double 15" horn per side. Double to make the throat larger and horn length shorter. A single 15" needs a quite long horn for good connection and loading tot 65/70 Hz. With a double 15" i can go down to 65 Hz -3/4 db with just 75 cm horn length.
The would look like the Fukntion one RES 9 low section. (http://www.funktion-one.nl/res9.htm)

I simulated the Emminence Gamma 15. This is a cheap driver, it almost dos'nt make any difference in cost for a single 15PL40 or double gamma 15 per side. The double gamma will go deeper in a shorter horn. The overal size will be a bit larger but that is not a big problem. Depth of 1 meter is the MAX.

Simulation double gamma on 75 cm horn with mouth 50 * 70 cm:
[img]images/uploaded/image26.jpg[/img]
(full space, 1/2 space and 1/4 space)

If a folded horn is an option, i can put the 15PL40 in a 1.2 meter horn with 65 Hz -1 dB.

[img]images/uploaded/image27.jpg[/img]
(full space, 1/2 space and 1/4 space)


The more expensive 15PL40 maybe have a stronger cone, has a stronger motor, tigther dispension, and i think a better overall construction.
I have never seen the gamma 15, but i know the 15PL40 is a well constructed driver. Would it be worth it to put this driver in a folded hoorn and still play up to 300 Hz with no distortion?

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Horn loaded mid/bass cab

by GC, Tuesday, March 08, 2005, 23:11 (4699 days ago) @ GC

Hi Michiel,

Do you mean a delay with timing?! Is use a DCX 2496 so i can set the
delays on the difrent drivers.

Yes, a digital delay corrects this well but I don't like the disadvantages of such an approach...

Personaly i think a straigth horn will work better than a folded one, but
i never did research on this.

A straight horn has less resonances in the upper range where the wave lenght becomes small, each part of the fold has its own resonance structure.

constructed driver. Would it be worth it to put this driver in a folded
hoorn and still play up to 300 Hz with no distortion?

300Hz should be possible but don't forget that the driver will also play higher frequencies (600Hz at -12dB is still very audible!)

ciao,

Bert

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Horn loaded mid/bass cab

by GC @, Amsterdam, Monday, July 25, 2005, 08:52 (4560 days ago) @ GC

Michiel,

I would like to know if you ever measured the frequency response of the mid horn loaded with the FE 103. Also i would like to know the mouth and throat
surface and the length of the mid horn.

Marc.

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