Tapped Horn For Car

[Binary110]

Its ALIVE!

Okay, so joking aside, the dual trio8 box was more than i was expecting.
The last couple of boxes left a little something to be desired, but this time, it drew a huge smile accross my face when i put that first heavy bass track on.

Never did the box complain, struggle or even come close. I noticed that marks car tends to buzz quite a bit a different frequencies, i almost confused it for distortion, but then quickly realized his tools in the back were bouncing off of the cabin walls and or themselves. lol.

More than enough power to get serious mirror shake, im talking about enough motion to make your rearview unuseable. On the ~40w we have to run it on, i'd say it definitely was up into the late teens early 120s.

A few tracks that were designed to only have standout bass if called upon were also played, no need for bass boost or loudness. The range of this sub is very impressive. Used when called upon, Discrete when not required. i guess the only way to describe it is dynamic range.

I've gotta run for now, Marks here. We've got some more testing to do.

[mwmkravchenko]

Well here comes the big test report.

My Computer and sound card are not on speaking terms today for some reason. But never fear a trusted assistant and I did some exhaustive testing indoors and this is what I have come to firmly believe.

HOLY CRAP BATMAN IT WORKS!

If you can find a configuration with two 8 inch drivers that beats this in the same size I'll eat my shorts. We did a nominal corner horn loaded measurement in my house. We came up with a 94 db/watt average spl from 35hz up to 80 hz. The woofer was not properly loaded to the floor boundary as it was sitting on a bed because of space constraints. But none the less that is what we got. If you had a proper floor loading you strap on another couple db's. I'm not kidding. We moved the sub around the room to different corners and the sound was very different.

The craziest part was when both of us looked at each other and wondered if the other guy felt his pant legs moving! I'm not kidding. The sub was 10 feet away and it was flapping our pant legs! I checked out the voltmeter and Adam checked out the SPL meter. We peaked in a 12 x 13 ft room at 128db with 16 watts input. We played some Organ tracks that even the great rapster Adam had to admit were PDG. And the room was pulsating. With 16 watts. I have created a monster. And to think we are working on a 12 inch version!

This last box iteration has pushed all the right buttons at the right time. It is just fantastic. In a car with proper wattage it will kill you. Even in my car with the sad little head unit I have it is a small force of nature. So I quit. This is about as good as it can get in this small of a space. A larger cabinet will give better results. But I'm talking larger to the tune of 400%. So I'm sticking with this one. I hope Adam posts his thoughts as we worked the afternoon in the shop and the evening fooling around with the UNHORN3.

Mark



That's me working so fast you can hardly see me!



My minions! Yep those are my boys. Not the two who test my boxes.



The little box that could can and duzzz.

[mwmkravchenko]

I have to clarify that comment on the power usage. I got my wires crossed on that one . We used an average of 16 watts or less but we peaked at 128 db with 36 volts into 4 ohms which works out to 310 watts. The sub behaved as spec'd if you look at the maximum SPL simulations from Hornresp.

Sorry for the misleading statement.

As for the bigger one with the dual TRIO12's it will come in two sizes. A smaller 260 litre box and a high efficiency box around 560 litres. Been working on this one since late summer. All I could think of when testing the 8 inch box was. What am I doing making this bigger? It's allready a monster as is!

Mark

[polviggen]

looks great, do you have any plans from this latest version ?

[Eva]

Hi Mark

I see that you continue with your experiments.

I don't want to sound rude, but a slot vented box of the same size with the same drivers and power will always produce more low end with less excursion than any of the designs that you have published to the date. No matter if your box can make things rattle or if the bass can be felt, in fact this does not require that much SPL, me and most people are used to these effects, it's not very hard to achieve (I routinely listen to a 500L corner bass horn with horn mid and tweeter on my living room).

All your boxes achieve the excursion reduction and efficiency improvement only above 70Hz, where it has limited use, although the frequencies that are easier to feel are in the 70Hz range (chest resonance and all).

The complex design that Patrick Bateman showed does achieve some tapped horn effect, excursion reduction and efficiency gain down to 30Hz.

http://lh3.ggpht.com/_wUDOCViv9D0/Sr...le-tapped1.jpg

[Brian Steele]

Originally Posted by mwmkravchenko

If you can find a configuration with two 8 inch drivers that beats this in the same size I'll eat my shorts. We did a nominal corner horn loaded measurement in my house. We came up with a 94 db/watt average spl from 35hz up to 80 hz.

Hmm... a decent vented alignment with those two drivers (e.g. 56 litres tuned to about 27 Hz) should achieve similar efficiency. The efficiency of two of those drivers wired in parallel works out to 87.5dB/1W, and corner-loading the alignment will add about 6dB to that. I'm skeptical but still intrigued .

Originally Posted by mwmkravchenko

The woofer was not properly loaded to the floor boundary as it was sitting on a bed because of space constraints.

Shouldn't make much of a difference at the frequencies of importance, unless it's a very big bed .

[Brian Steele]

Originally Posted by mwmkravchenko

A smaller 260 litre box and a high efficiency box around 560 litres.

Those boxes are actually huge (260l = 9.18 cu.ft.). Are those volumes correct?

[MikeHunt79]

I've been tempted to try a TH in my car, right now I'm using an Autotuba which is a FLH which works but is a little to large.

I've been aiming for a normal TH design. with 40Hz tuning frequency:



The gray line is the last input parameters I could find for your dual MCM 8" UNIHORN enclosure, both are modelled at 1pi with 2v input (which is more than 1W as the drivers are parallel)...

Another thing to note is that the higher tuned box is around 60L instead of around 40L, so a fair bit bigger, but this will still be smaller than what I have in my boot/trunk right now!

I have yet to fold it or build it, I was only playing around with hornresp, but I'm hoping for cabin gain to boost everything below 40Hz, plus I'm not really too concerned with things going on below 30Hz, as my car makes enough strange noises as it is, the joys of a French car!

Patrick Bateman: Have you got anymore info on that crazy box with 3 x MBM 8's?

[mwmkravchenko]

Originally Posted by Brian Steele

Those boxes are actually huge (260l = 9.18 cu.ft.). Are those volumes correct?

Those boxes are for the Dual TRIO12 version. One matches the sensitivity of a well designed ported box but is smaller by about 100 liters and goes down to 18 hz. The larger one has 95db/watt 2 Pi efficiency and goes down to 16 hz.

My statement about the latest UNHORN is to be taken in it's context. The box is 10 x 20 x 24 just under 3 cubic feet (78.6 liters) It has an efficiency of 96 db/watton average from 35hz on up. I don't have fancy computer driven measurements as my sound card is misbehaving at the moment. But I did take this set of measurements at 1 meter at 1 watt into 4 ohms (2.00 volts 2 pc TRIO8 in parallel)

30hz 84db
35hz 92db
40hz 100db
45hz 101db
50hz 96db
55hz 95db
60hz 95db
65hz 95db
70hz 94db
75hz 93db
80hz 92db
85hz 85db
90hz 97db

These were taken with corner loading and using steady state sine waves so there is a discernible pattern of null at 85 hz because at different room placing there is a slightly different result.

[Patrick Bateman]

Originally Posted by MikeHunt79

I've been tempted to try a TH in my car, right now I'm using an Autotuba which is a FLH which works but is a little to large.

I've been aiming for a normal TH design. with 40Hz tuning frequency:



The gray line is the last input parameters I could find for your dual MCM 8" UNIHORN enclosure, both are modelled at 1pi with 2v input (which is more than 1W as the drivers are parallel)...

Another thing to note is that the higher tuned box is around 60L instead of around 40L, so a fair bit bigger, but this will still be smaller than what I have in my boot/trunk right now!

I have yet to fold it or build it, I was only playing around with hornresp, but I'm hoping for cabin gain to boost everything below 40Hz, plus I'm not really too concerned with things going on below 30Hz, as my car makes enough strange noises as it is, the joys of a French car!

Patrick Bateman: Have you got anymore info on that crazy box with 3 x MBM 8's?

What would you like to know?

The AutoTuba is a very impressive design - Bill F knows his stuff. It is the flattest box that I've ever measured in a car. Unfortunately, that's actually A Bad Thing in a car. I've found that boxes that measure flat in a car sound too lean. Nonetheless, it's musical, dynamic, inexpensive and relatively easy to build.

The TH-Mini clone *might* be my favorite of all the tapped horns I've built. The last octave is completely AWOL, but above that, it's ridiculously efficient and the bass is very 'tight.' Distortion is a non-issue with this box - there's a big fat null between 100 and 200hz that just zeroes out distortion. The downside to the TH-Mini is that there isn't much output from 20-40hz, the woofer is relatively expensive ($150), and it's fairly large (close to 5 cf.)

The Triple8 is probably the best compromise. It plays lower than the TH-Mini clone, absorbs three times as much power as the AutoTuba clone, has more displacement thanks to a higher SD, and is the smallest box of the three. The TH-Mini clone is audibly "cleaner" from 100 to 200hz, but it should be - it uses a woofer with lower distortion and lower inductance.

My solution to get "the best of both worlds" was to simply put the Triple8 in my trunk. The rear seat filters out high frequencies, and distortion along with it. (I was running the TH-Mini clone on my back seat. It was designed to take up one seat. It's light enough not to scuff up the upholstery.)

I would upload plans if I had them. But the Triple8 is the exact same box as the Th-Mini clone, but with an extra piece of plywood that extends the path. You can see it in the pics. As long as you get the mouth right you'll be fine. Just take a look at the pics, and draw it out on your plywood. The outer dimensions are 24" x 24" x 9". The plans for the Th-Mini clone are in "The Smallest Tapped Horn" thread.