Horn vs Open baffle bass

[Magnetar]

I find properly designed front loaded bass horns are superior to open baffles in all performance areas except bandwith.

[rick57]

Hi Paul

Yes I’m your fellow MACer. You must be professional poster! I’ve been having a debate with another MAC DIYer on the same issue.

The general consensus sound wise appears to be a trade off:
detail & fidelity vs dynamics and volume; or
hard/ heavy/ rock/ disco/ elecronica and vs HT most other music.

Any agree/ modify?


Cheers Richard

[paulspencer]

Originally posted by Magnetar
I find properly designed front loaded bass horns are superior to open baffles in all performance areas except bandwith.

Magnetar,

Could you elaborate a little more?

It is one thing to say that A sounds better than B, but another thing to explain WHY.

As has been discussed, horns are sealed boxes on one end with an acoustic transformer on the other. The result is more efficiency and output for the amount of distortion that would normally come from a sub with much less output. This is achieved by making the bass more directional. This means that the interaction with the room is reduced as the relative proportion of direct to reflected sound is increased.

I am probably mistaken in saying their polar response is cardiod, it is more likely to be like the front half of a dipole.

Dipoles aren't pressure loaded by a sealed box and this eliminates box coloration and I suspect that this makes them a little more "accurate."

I can't see how dipoles would actually be any better with room modes than horns. If I'm mistaken, then could someone expand on why?

What if an attempt was made to get the best of both. A dipole where both the front and rear wave was horn loaded. Or, perhaps more practical, an Infinite baffle where the front wave is horn loaded.

[johninCR]

I believe they excite less room nodes due to cancellation in the directions parallel with the front baffle. eg, you stand on the side of a dipole and you hear very little bass. The front and back waves meet as they disperse to the top and sides and cancel each other out leaving only those propagating in the front and rear directions.

The same is not true for a horn. The waves exit the mouth and disperse with nothing to cancel them out on the top and sides.

That's why a dipole sub must move a lot more air to create high SPL's, because a significant portion of the energy is lost due to cancellation of the waves at the perimeters.

You can horn load both a front and rear wave of a driver, but that's much more difficult to get right than either a typical front loaded or rear loaded sub. In doing so you wouldn't get the dipole benefit of exciting less room nodes anyway because your effective baffle width would be so wide due the long lengths needed for bass horns that there would be little, if any cancellation at the sides.

[HeatMiser]

Originally posted by paulspencer
What if an attempt was made to get the best of both. A dipole where both the front and rear wave was horn loaded...

Wow. That idea put a grin on my face, just thinking about it. The sheer wanton impracticality makes me want to run out and try it, if only I had the space.

Please don't take offense, it's really a very interesting idea - I just thought immediately about the unwieldy size of many bass horn designs, then doubling the depth to horn-load the back, then needing to place the whole thing a couple meters out into the room in order to take advantage of the dipole aspects. If sound quality is inversely proportional to WAF, this monster would be world-class.

[Coolin]

There are horn designs that load the front and back. The front is not loaded all the way to the bass.
In the tests i have done there was definately less slam with the dipoles than my horns. This was on 1/2 inch chipboard though. It colored the sound alot ofcourse. Im sure it would improve alot with a very heavy baffle but doubt that it could slam like horns.

Collin

[paulspencer]

Many talk about "slam" in relation to horns, but I wonder what they mean in more precise terms. Are dipoles being compared at the same SPL level?

Lower distortion means that speakers don't sound as loud for a given SPL. So consider this: play dipoles and horns in a comparison at what appears to be the same volume. Due to the lower distortion, the horns may not sound louder, but if measured, the SPL may in fact be greater. Yet, the impact of the bass on your body will be felt as greater as it is in fact playing at a higher level. Perhaps this has a part to play in the "slam" factor that is often talked about.

Or perhaps it is something else ...

[phase_accurate]

You can horn load both a front and rear wave of a driver, but that's much more difficult to get right than either a typical front loaded or rear loaded sub. In doing so you wouldn't get the dipole benefit of exciting less room nodes anyway because your effective baffle width would be so wide due the long lengths needed for bass horns that there would be little, if any cancellation at the sides.

A P.A. guy that I know, once swore by some reletively small open-backed horns that he used for the reinforcement of acoustical instruments.

Regards

Charles

[paulspencer]

Regarding my idea ... horn loading front and rear is probably a bad idea, but infinite baffle to the rear or an open back seems like quite a feasible idea. I expect the result would be less coloration.

[mikee12345]

re:colourations
i really dont think this is a factor in basshorns

because: colourations in the midrange horns(and HF) are due to
parallel walls,bell mouth modes, etc etc

the waves are so long on the basshorns it doesnt matter :-)

aslong as the approximations of the 'expo' horn then no worrys
my 40hz horn went fine first time sounded great

Im building 30hz next time with jbl 2226

It comes down to what you want
a 40hz horn will be easier and smaller(ofcourse most music is here or higher)

Try both and tell us what you think. :-P

spend more on amps + lots of cheap speakers
or lots of wood and 1 speaker and 1 amp :P
my 40hz horn caused my US $ 9 woofer sound okay! cant pick it out from my jbl 2226 until the 33hz starts then the horn has no output and the low tuned jbl shines ;-)