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what do those compromised small bass horns actually sound like?
what do those compromised small bass horns actually sound like?
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Old 26th October 2005, 11:44 AM   #1
paulspencer is offline paulspencer  Australia
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Default what do those compromised small bass horns actually sound like?

I'm hunting info on small bass horns to handle 40 - 120 Hz

Bill Fitzmaurice Autotuba and Table Tuba look interesting but most of the comments I hear about them are "wow, impressive for an 8inch driver" but what I want to know is are they accurate when they are equalised flat?

I've heard one person build an Autotuba who is now selling because he didn't find it "suitable for audiphile use" ... but I did note he didn't use eq.

The lab horn looks great but just too big

I could handle something that is more like 1000 x 600 x 450mm

So the big question is: what are your experiences with compact bass horns? Can a cheap 8" subwoofer like the Tangband W8 740C match a good low distortion direct radiator up to 80 or 120 Hz?
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Old 26th October 2005, 01:14 PM   #2
paulspencer is offline paulspencer  Australia
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Another question: is it feasible to use stuffing in a bass horn like in a TL? The purpose would be to reduce those peaks ...
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Old 27th October 2005, 12:42 AM   #3
jeff mai is offline jeff mai  Australia
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IMO, you'd be much better off using 4 drivers in a box of that size to achieve efficiency gains instead of horn loading. Or try Geddes' Acoustic Lever if you want a technical challenge.

There ain't no such thing as a small bass horn. If the "horn" is long enough with a too small mouth, it behaves as a TL or a pipe. If its mouth is correctly sized but the "horn" is too short it's more of a directional baffle. There is a good reason that many of the space challenged Europeans and Japanese use bass reflex cabinets (Onken style) with their mid-range horns.

Bass horns are great but they must be big (I owned a pair of the Shearer horns linked in another of your recent horn threads - each is bigger than three fridges and only went down to 40Hz!)

I suppose it might be fun to try to squeeze a bass horn as an exercise just to see what can be achieved. If you're after high performance straight away, I'd try another approach. This from a huge fan of horns.
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Old 27th October 2005, 02:42 AM   #4
pjanda1 is offline pjanda1  United States
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This is a timely thread for me. I've been looking for opinions of Bill Fitzmaurice's designs for some time. I have found few people outside of his forum that have built them and tried them, and even fewer people who have done a legit comparison to a conventional sub. I have found a couple of people who's opinions I trust that say they work as promised.

Most of the critiques I have seen say that it won't work according to conventional theory and that they don't model well on current software. Bill counters that they don't use conventional theory and the current software doesn't model them correctly. It seems to me that some of the criticism also stems from personal feelings towards Bill Fitzmaurice. He does sound like a colorful character.

I think the only solution is to build one and measure it. Hopefully someone nearby will have a nice conventional sub I can compare it too. I've got everything I need to start building, but Home Depot's panel saw is burned out and my little car can't hall a full sheet of plywood home. Evidentally they'll have it fixed next week. If the sub (Table Tuba) works as promised I'll be very pleased. If not, it wasn't that expensive. I'm always a sucker for the weird stuff.
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Old 27th October 2005, 03:25 AM   #5
BassAwdyO is offline BassAwdyO  United States
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I have built the auto tuba. I modified the design somewhat to use 3/4" MDF instead of the half inch ply that the design called for. But all in all I'd say it was a good little thumper, definately loud, but I'd say it had a bit of ringyness to it, especially in the higher bass. I wouldnt call it hi-fi. It didnt go very low(40hz at best), and it was difficult to tell when the driver was under distress(I ended up frying that little 8incher actually, or a buddy of mine did, but I'd have probably ended up doing it myself if he hadn't beaten me to it).

On this very forum there is a thread with measured frequency response from the autotuba and either a tempest or a shiva, comparing the two. You might want to seach for it.

I actually bought another one of the drivers used, but I'm going to use it in an entirely different application this time. I was going to go with a small ported box tuned to ~30hz and power it with a 40wattRMS Magnat amp that MCM also sells. I have been a bit preoccupied lately with other things, but I think this will yeild similar results(without the high bass ringing) and perhaps a bit more extension. When I try it out I'll let you all know how it goes.

BTW.... I didnt EQ it.
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Old 27th October 2005, 03:38 AM   #6
tade is offline tade  United States
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what is an acoustic lever?
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Old 27th October 2005, 03:51 AM   #7
pjanda1 is offline pjanda1  United States
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I have of course searched this forum and many others. I think "a thread" (as in one) with measurements is the point I was trying to make. It is good to hear more from someone who has actually built one.


Paul
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Old 27th October 2005, 06:01 AM   #8
BassAwdyO is offline BassAwdyO  United States
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Tade, an acoustic lever is something like a bandpass which uses a passive radiator instead of a port, and instead of a normal passive radiator it uses a small passive radiator which is connected to a larger one via a rod, and there is a airspace between the passives which is a seperate chamber. There is much more to it, but that gives you a basic idea. Do a google and you might find something which explains it better
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Old 27th October 2005, 10:45 AM   #9
slowmotion is offline slowmotion  Norway
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Hi

Quote:
Originally posted by jeff mai
There ain't no such thing as a small bass horn.
I agree with Jeff.


cheers
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Old 27th October 2005, 11:12 AM   #10
paulspencer is offline paulspencer  Australia
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Small is subjective!

When I say small, I mean small in relative terms ... "small" for a bass horn. Something that occupies a foot print 40 x 60 cm, but it can be floor to ceiling, or have a few stacked floor to ceiling. As long as I can get them through the door.

I think I could live with one or two "small" bass horns the size of the Table Tuba, although I'd prefer rectangular shape.
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