Help! With a rear horn loaded scoop bass bin

[planet10]

Originally posted by bob4
To get a low cutoff frequency and a flat response down to it, you have to go for a looooong horn with a big mouth, right?

You can make the horn shorter by making the throat larger, decreasing efficiency and distortion -- it has an effect on bandwidth as well IIRC.

According to the tables in the Dinsdale paper, the scoop design has a low cutoff frequiency of about 80- 100 Hz.

That is about right

I remember hearing, that a couple of horns stacked properly act like one big horn (like in the picture you posted).

To do it properly, you design the big horn and then slice it into pieces -- you need a driver for each slice.

Would that mean I would always have to drag around all the four Bins??

Yes

And last but not least: The paper doesn't say anything about how to match your speaker to the horn. Can I just make an ideal scoop design according to it, and then mount the drivers in?

The Dinsdale article was written a long time ago and should be considered as a background. There is a Marshall Leach AES paper that goes into great detail wrt mating a driver to the horn. It is the next text in the puzzle.

dave

[bob4]

Originally posted by planet10

The Dinsdale article was written a long time ago and should be considered as a background. There is a Marshall Leach AES paper
that goes into great detail wrt mating a driver to the horn. It is the next text in the puzzle.
dave

This horn construction thing gets more and more exciting.

The AES paper by Leach has already been mentioned a few times.
Does anybody in here have a copy of it? I know I can order it from the AES directly for about 4-5$, but the shipping would probably take a long time????

Please post a link or something, or E-Mail it to me (if possible)

planet10,

what does IIRC mean?

[planet10]

Originally posted by bob4
what does IIRC mean?

If I Recall Correctly

dave

[bob4]

HEy Folks,

Some nice person mailed me the AES paper by Leach.

As soon as I have read through all the material I've got with the help of you all (special thanx goes out to planet10 & mgoedeke), I will make up a design.

regards,

bob

[Brett]

Originally posted by bob4
I know I can order it from the AES directly for about 4-5$, but the shipping would probably take a long time????

For future reference, AES email you a PDF of the paper you purchase, usually within a couple of hours (if you pay by credit card). Each PDF is at least a meg in size, so if you order a few, make sure you have a large enough mailbox!
Cheers

[mgoedeke]

Now what one needs is a program that would by means of an iterative process give one the possible horns suitable to a certain driver. An analogy to an alignment as in the case of ported boxes would be in order. I myself don’t have that paper so I am guessing but perhaps it gives one that as well. As I see it, it gives one the means of getting the T/S parameters ideal for a given horn (with two knee points, a given efficiency and bandwidth) T. Danley supposedly has such a beast (amongst others) and so does AJ Horn, but that is currently out of my reach. Any ideas?

Martin

And credit where credit is due to other forum members and the contributers to the LAB Horn project. Read through that for lots of quality info, especially the earlier posts in the design phase.

[planet10]

Originally posted by mgoedeke
T. Danley supposedly has such a beast (amongst others)

Tom has said that his software is a MathCad worksheet based on Leach's paper that was written by a student intern (IIRC).

dave

[mgoedeke]

Then perhaps I have some math students to speak to (or my dad even, just he doesn’t have the time for such things) My math skills are rather scary and the only modeling I could do is the odd population model and only by hand. That is something for after the exams though. I don’t suppose somebody has such a thing, or? Perhaps we should open another thread on bass-horn design (or did my search miss something)

[bob4]

Originally posted by mgoedeke
Perhaps we should open another thread on bass-horn design (or did my search miss something)

Why not? I guess discussing different horn designs and mathematical approaches could get quite interesting.