My first Tuba

[BassAwdyO]

oops... forgot to attach the pic

[BassAwdyO]

After hooking it up and listening I'd say the in room usable response ends at ~40hz. However comparing to a sealed box its got to be at least 10db more efficient. I havent done any measurements yet, but its more than twice as loud. Amazing....

Now I REALLY want to horn load my Tumult.... a 30hz horn would be insanely loud.

[simon5]

You could use the plans from Adire Audio for a Tempest Horn...

[mwmkravchenko]

Muhhhaaahhhhaaaa

Mark

[BassAwdyO]

Indeed... I could use the tempest horn plans, but bill informs me that the tuba 36 will work well...

decisions decisions.... one free, one $10....

I think i'll buy bill's design and see what differences there are between that and the tempest horn. Mostly I'm looking for high efficiency(well it doesnt have to be insanely high, just better than the 88db that the tumult has in a normal enclosure) and a low cutoff.

Bill suggested the 20" slim horizontal baffle slim version (which has less extension but a higher cutoff

I figure though, if you're gonna go, why not go all out... Couldnt I just do the 36^3 version? I guess that would mess with the compression ratio possibly since the 36^3 version is recomended for 2 15's..... the Vertical baffle configuration is also supposed to give extension to 15hz which I personally would love. I guess that wouldnt work so well with the low FS of the tumult, but I dont see why just using a smaller rear chamber to raise the effective resonance up to where it would work well. HMMMMMM

I'm no horn expert... looks like I'll have some learning to do

[paulspencer]

Horn loaded tumult? Is that going to be put in a bomb shelter or do you have bullet proof glass?

I'd be very interested to hear what you think of the AutoTuba and how it compares with a cheap 8" to your Tumult in terms of SQ. Probably difficult to compare since the response would be so different.

One possibility with horns would be to use some "compact" midbass horns like the AutoTuba to get down to 40 Hz, then cover the bottom end with a pair of vented Tumults. If you have the best quality of driver you can get for the midbass horns, you could have very accurate low distortion bass where the ear is more sensitive. I suspect the extremis would not have the chance to use all of its excursion and from that point of view it might not have any significant advantage over a typical midbass except for the linearity of the motor design combining an XBL2 motor with shorting rings.

[mwmkravchenko]

I figure though, if you're gonna go, why not go all out... Couldnt I just do the 36^3 version? I guess that would mess with the compression ratio possibly since the 36^3 version is recomended for 2 15's..... the Vertical baffle configuration is also supposed to give extension to 15hz which I personally would love. I guess that wouldnt work so well with the low FS of the tumult, but I dont see why just using a smaller rear chamber to raise the effective resonance up to where it would work well. HMMMMMM

If you have the plans you find that there is indeed good low end response with the tuba 36. THat is at the expense of efficiency. With a good low end eq you could indeed have some truly thundering bass.

I downloaded the plans a couple weeks back. Going to put some 15" to work in a different configuration. THe boxes will be setup with dual 15's.

Just a note on timber between driver loading. You may have already noticed that there is a difference between the bass that comes out of the autotuba and what would come out of a normally loaded 8". It's basically a much cleaner sound. If you go with a different driver loading at to high a frequency you will definitely notice the difference. That will have have to be determined by you and some carefull listening.

I'd love to build them and listen along with you. But unfortunately I'm moving in two months and have enough stuff stuff do move as is. In the new place!

MArk

[GM]

Greets!

Drivers like the Tumult are best suited for BHL to take advantage of the super low Fs/high Xmax, so a conical expansion cornerhorn should yield the best 'bang'/floorspace. Obviously, the longer you can make it the lower it will go with gain, but with a conical flare and sufficient length it should have >100 dB sens. to Fs if the corner construction is rigid enough.

That said, I ~agree with Paul, use midbass horns down to ~40 Hz and a Tumult BP (or two) for sub duty.

GM

[paulspencer]

GM, I'm not exactly sure what you are suggesting ... bandpass, horn for the Tumult?

What do you mean by BHL?

Horns seem a curious thing to design for using typical sub drivers. I've tried out my AV12s in hornresp, and it seems that they don't get quite as much output as I'd expect considering their power handling and excursion. I get very little cone movement, then suddenly the excursion shoots up at the tuning point.

[GM]

Greets!

I said I agreed with you, with the caveat of putting the Tumult(s) in a bandpass cab(s) and if a Tumult or similar sub driver is horn loaded, that it be a back horn, preferably corner loaded.

WRT the horns unloading too soon, I assume it's because you're making the length a 1/4WL long rather than an acoustic 1/4 WL, which will be somewhat longer based on its 'M' factor. Of course, just like any other vented or sealed design, it unloads/compresses based on the alignment below Fc.

GM