RT-2 Horn sub, the result

[jbell]

I'm surprised you didn't go the 1/4 wave pipe route (or TH, however you want to describe it.)

Like this.

It'd definitely go low, be an easy build, and not be any bigger than what you already have.

My opinion, anything over 120db from 30-100hz in house is ridiculous.

[Elbert]

I've sort of gone off the idea of closed systems..

First of all; as you say, the selection of good drivers is not all that great, and secondly, the low end extension you can get from a well tuned BR system seems hard to beat.

There is also the issue of greater cone excursion with closed boxes, and we don't like that.. (that's why we find horns so sexy..*s*)

Speaking about cone excursion, things are starting to get interesting here as I'm running hornresp and WinISD sims in parallel here to check for alternative usefulness of interesting drivers...

bearing in mind that the horn will always need some EQ massage to pull down the frequencies where it is most efficient, when a driver is driven to max excursion both the horn and a BR enclosure of similar volume, there is not that much benefit to be had from the horn.

On the contrary, the BR will win out in bass extension!

oh dear...

[Elbert]

jbell,

I tried a sim with your suggestion..and it didn't really look that good..

And yes, 120 dB is perhaps a bit ridiculous, at least continuous.

But then again, music is dynamic, and being able to reproduce transients with low distortion must be conductive to good reproduction quality?

[AKN]

Elbert,

In your quest for hornbass, why not simply go for a larger horn ?

[Elbert]

Anders,

In response to your suggestion:

1:

I live in a rented apartment, not on a farm.

2:

I have not completely lost it... yet..

But yeah, a larger horn sure is a tempting idea, but it just seems that with the dimensions involved, it's difficult to justify compared to what one can achieve with modern drivers in a conventional enclosure.

The RT-2 horn is after all quite managable as a piece of furniture (if veneered it will actually become a rather nice TV-stand), but anything significantly larger will just be difficult to accommodate in a domestic environment..

[AKN]

Elbert,

I thought the added smiley should clarify my intention with my recent post

I would not write so nicely about the RT-2 horn if I had not built and listen to it myself. I really like the sound it produces, low distortion and a fast stop (essential for me).

I think something is wrong if you cannot get 40Hz out of your horn. A sim that include the whole horn path as well as measurements should clarify the situation.

[Elbert]

No malice intended in my reply to your previous post, quite the contrary!

The reasoning behind not adding the last "external" section to the horn model I have "borrowed" from Bjornos post, was that this was actually calculated in by hornresp due to the quarter space boundary condition.

I must however say I'm not 100% convinced about this, but then again, with low frequencies and room interactions, it is sometimes difficult to draw the line...

Well, I've not given up completely on the horn yet, after all, the swap from the ill chosen Delta pro to the SEAS 13" revealed that this horn may yet have potential to be realized through selecting the right driver..

Having taken a closer look at both the gamma and the visaton, their relatively limited Xmax has given me some second thoughts, as this might not only limit them in the horn at lower frequencies, but also for secondary use in a conventional enclosure... A peerless SLS woofer with 10mm Xmax might be a more interresting option in that respect..

http://www.mamut.net/dynabel/subdet329.htm

[tinitus]

Originally posted by Elbert

A peerless SLS woofer with 10mm Xmax might be a more interresting option in that respect..

And cheap...last time I looked, about 50 EUR

[tinitus]

Just fore the record...about Xmax

As far as I know, every other box principle than closed will unload the driver below system resonance, with the result of excessive and uncontrolled cone movement

Now I remember once in the past when I mounted an ordinary hifi 5" midwoofer in a friends small horn, a Lowther mini acousta, which was one of my own first
This small Focal midwoofer had played wonderfully in a small closed box
But I was really surpriced that in this horn the driver moved excessively, even at low SPL
It had me puzzled, why so when no other fullrange did that, and I never got to understand why

Well, today I know why, at least I think so...the driver simply had too low Fs to work in that horn, and got unloaded too early, at a relative high frequency, where there is stll lots of music energy
I know, probably there could be other reasons as well, and it may not be that simple

A short while ago I mentioned in here that I didnt fully understand the quest fore such huge Xmax, as my double 8" ScSp in closed doesnt move much, even at loud SPL
The answer was that I doesnt play loud enough

But sure, I like Xmax and always consider that when looking at a woofer...only thing is, that it has been stated more than once that a similar woofer with shorter Xmax will always sound better, more or less

Sometimes things could seem a little more tricky than expected

[jbell]

sorry, accidentally had it set for 2 drivers....

This should look better.