A Tapped Horn Experiment

[3vil]

The size of the box is dictated by the driver(s) and the tuning. The type of vehicle it's in will not change the size, other than trying to fit in a small trunk/hatch. The vehicle cabin gain will change how a box responds.

[Triticum Agricolam]

Its finally nice to see someone who like this stuff as much has me and has some real knowledge. you used to compete in the early 2000s by chance? i used to travel all over and when i could afford to compete(was a teen up till i was in my early 20s). i used to live in the forums but everyone i used to know seem to be long gone.

Nah, I've never competed. Part of me wants to sometimes, but its easier (and cheaper) for me to just live vicariously through my customers :-)

[baron_of_bass]

Its finally nice to see someone who like this stuff as much has me and has some real knowledge. you used to compete in the early 2000s by chance? i used to travel all over and when i could afford to compete(was a teen up till i was in my early 20s). i used to live in the forums but everyone i used to know seem to be long gone.

Nah, I've never competed. Part of me wants to sometimes, but its easier (and cheaper) for me to just live vicariously through my customers :-)

Don't worry bro, you can have all my 159.9 bass race trophies when I win them ???

[Karkov]

Wow, amazing write up, over my head, but amazing. I like how with the finished product you can see the sub RIGHT there...

EDIT: when these get more common, or easier to get a design for one, the question/debate will come from people like me who own a full size SUV and I am looking at a small set up but have room to fit a box like that horn. With a proper design I can easily assemble it myself, and would save money buying only one (or perhaps 2) drivers instead of 2 or 3 or even 4 if the output was the same. Depends on IF* the output was comparable though, and if time meant nothing to me (box building aspect) or how easy it would be to acquire a design. so cost vs output vs time vs etc. etc. Kind of interesting. I love the science behind all aspects of car audio, I don't understand very much of it though, thinking about some aspects make my head dizzy, lol.

Same here, Very interesting. If you were to do one of these boxes in a SUV, How big would it need to be and what size sub or (subs) would you use to really get down ?

this is a little new for me to run it in a daily but the space is 49" wide x close to 4' tall and 3' deep so....

[Triticum Agricolam]

Same here, Very interesting. If you were to do one of these boxes in a SUV, How big would it need to be and what size sub or (subs) would you use to really get down ?

So it really is going to depend on what your goals are. The advantage of a horn like this is its space efficient for the output it produces, it has wide bandwidth and sounds good, and it lets you use a smaller/less expensive sub, usually.

Where I think this design could really shine would be a scaled up version for a 12" sub. Something like a FI SSD 12 or Q 12 would work well and would let you put a lot more power into it. Two of those would take up roughly a 18" H x 48" W x 28" deep space, which should fit in the back of a lot of SUVs. It would be about the same size box as two 15"s, but would give better performance.

[ckeeler11]

how does the performance of this compare to the autotuba from Bill Fitzmaurice?

[Triticum Agricolam]

how does the performance of this compare to the autotuba from Bill Fitzmaurice?

The AutoTuba is tuned to 40 Hz, so this horn should have more low end output. The AutoTuba might beat it higher up though. I'm in the field right now but when I get home I can compare the two in HornResp and post the results.

I've actually got an AutoTuba sitting around. I'll drag it out next time I'm measuring and then we will know for sure how they compare.

[ckeeler11]

how does the performance of this compare to the autotuba from Bill Fitzmaurice?

The AutoTuba is tuned to 40 Hz, so this horn should have more low end output. The AutoTuba might beat it higher up though. I'm in the field right now but when I get home I can compare the two in HornResp and post the results.

I've actually got an AutoTuba sitting around. I'll drag it out next time I'm measuring and then we will know for sure how they compare.

Cool.

[Jessica]

Same here, Very interesting. If you were to do one of these boxes in a SUV, How big would it need to be and what size sub or (subs) would you use to really get down ?

So it really is going to depend on what your goals are. The advantage of a horn like this is its space efficient for the output it produces, it has wide bandwidth and sounds good, and it lets you use a smaller/less expensive sub, usually.

Where I think this design could really shine would be a scaled up version for a 12" sub. Something like a FI SSD 12 or Q 12 would work well and would let you put a lot more power into it. Two of those would take up roughly a 18" H x 48" W x 28" deep space, which should fit in the back of a lot of SUVs. It would be about the same size box as two 15"s, but would give better performance.

So if you had a mayhem 10" would you throw it into one of these horns?

[Patrick Bateman]

how does the performance of this compare to the autotuba from Bill Fitzmaurice?

The AutoTuba is tuned to 40 Hz, so this horn should have more low end output. The AutoTuba might beat it higher up though. I'm in the field right now but when I get home I can compare the two in HornResp and post the results.

I've actually got an AutoTuba sitting around. I'll drag it out next time I'm measuring and then we will know for sure how they compare.

I built myself a clone of the AutoTuba a few years ago. I'm not sure if I'd recommend it, unless people were prepared to cross it over above 100hz, maybe even 150hz.
The weird thing about horns is that they totally unload below the tuning frequency. For instance, if you have a front loaded horn with an 8" woofer that's tuned to 40hz, that horn will behave exactly like a sealed box below the tuning frequency. So that was the issue that I had; the box was punchy, efficient and loud, but below 40hz it was no louder than a 8" woofer in a sealed box.

I think the box might be interesting if you put a REALLY big amp and a REALLY durable woofer in there. Over on diyma I attempted to do just that, when I made something I called a "super autotuba" that used a TC Sounds 8" instead of the MCM 8" in the autotuba. The TC Sounds woofer costs six times as much, but it can take a lot more abuse than the MCM.

Basically it's not a BAD sub, but the octave where it shines is from 60-120hz. So using it with a 80hz lowpass is basically throwing away the most efficient part of the design.