Collaborative Tapped horn project

[moray james]

US # 2 871 972 sorry I can not shrink the picture enough to post here you will have to Goolle the patent and have a look.

[rick57]

Hi William

When philpope in the discussion at http://www.speakerplans.com/forum/f...?TID=8329&PN=10
said

“I think when William said 2:1 compression ratio, he meant the ratio of Sd to the end of the horn, NOT the cross section where the tap is.
I assumed that the lowest bass response would be obtained by tapping the driver into the horn where the cross section is the same as Sd so I make the throat of the second section in the model equal to Sd.”

Was that what you meant?

Cheers

[cowanaudio]

G'day Paul

Looking at your sim, I'd guess you'd be about 4dB down at 22Hz. That is a good compromise for reduced size. The tap will smooth out the dip above the low cutoff. How about you sim the different drivers being offered for the comparison?

Rick

The compression ratio is the area ratio between the driver and the throat of the horn. If your driver Sd is 800CM^2 then if the throat is 400CM^2, you have a 2:1 compression ratio.

Cheers

William Cowan

[paulspencer]

I'm collecting driver data so that I can simluate them all.

Drivers:
AE speakers AV12 2nd run
Rythmik DS12TC
Peerless CSX 10 & XLS12
PHL 5230
Eminence Kappa pro 12
Eminence Alpha 15
Lambda 15TDM
JBL 2035

For the last 2 drives, I don't have parameters for CMS, RMS and MMS which are necessary for hornresp. A quick search didn't turn up anything. Does anyone have data on them?

So far the AV12 parameters look very good according to the target range. It meets all criteria except being slightly under recommended SD (not a big deal). I have found it also models very well in a bass horn generally. Not surprising since it is similar to the Lab driver which was designed for bass horn use.

[paulspencer]

Hornresp simulation



AV12 - red
PHL - green

The other 2 drivers are the Alpha 15 and the Kappa Pro 12. The kappa is very similar to the PHL except that it has a peak at the bottom end due to the much stronger magnet. The alpha has the extreme low peak due to the crazy high Qts and very weak magnet, but the dip is the biggest. The XLS not shown as it is fairly similar to the AV12. The Rythmik is similar to the AV12 except that its bottom peak and dip and less. CSX is similar to the Rythmik but less efficient.

Of them all, I suspect the AV12 will work out the best. My gues so far is that if the magnet is too strong, and hence the Qts is too low, the end result will be drooping bottom end.

Simulation is for 1w of input in a corner.

[rick57]

Paul

What I have:

15TDM JBL 2035
Fs 35 48
Re 6.6 3.9
Qms 4.5 5.0
Qes 0.35 0.36
Sd 855 880
Vas 405 140
Xmax 3.3 7.1
(Le) 0.20 0.25
Cms 0.3 ?
Rms 3.0 ?
Mms 70 85

[GM]

Originally posted by rick57
I tried to look up Klayman’s 1962 patent
http://patimg2.uspto.gov/.piw?Docid=...iew+first+page
but it doesn’t allow access or display for me.

Greets!

Go 'fetch': http://free.patentfetcher.com/Patent...h&PN=3+047+090

GM

[cowanaudio]

G'day Paul

Hornresponse will let you back calculate the values you are missing. Enter all the values you have and double click on the empty field where the unkown value should go. It will work it out for you.

It looks like the AV12 will work well in this tapped horn. I hope you have enough power available to explore it's limits. An Aussie Monitor AM1600 could not give an 830500 any grief before going into clipping.

Cheers

William Cowan

[AJinFLA]

William,

What sort of GD are we looking at with the 18hz horns?
Did you reverse mount one of the 830500 motors?

Cheers,

AJ

[paulspencer]

William,

I seem to find the AV12 to be very good for bass horn use. I have an Europower EP2500 to power it, which has 2 x 650w into 4 ohms. To drive just one in a tapped horn, I have 2.4kw bridged into 4 ohms (yes it's stable down to 2 ohms). Do ya think that's enough?!

What REALLY surprised me the other day - I saw it clip when driving them in OPEN BAFFLE!

It was just once for a brief moment. That's only the 2nd time I recall in a few years that I've had it. Before that amp I had tried out two 2x450w pro amps and both of them clipped before the subs ran out of steam for music. Of course I use a rumble filter ... when I upgrade my mains to keep up, then they will have more of a challenge.