8" vs 10" truck Tuba

For livingroom sound better than in a theatre.
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iSurfSouthChinaSea
Posts: 17
Joined: Fri Apr 17, 2020 11:13 am
Location: Saint Petersburg, Florida

Re: 8" vs 10" truck Tuba

#76 Post by iSurfSouthChinaSea »

I would love that response in my kei van. ^^^ I notice things improve when I open the sunroof. I think the boxy interior volume in this particular van is not ideal.

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Bill Fitzmaurice
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Re: 8" vs 10" truck Tuba

#77 Post by Bill Fitzmaurice »

What happens when you open the sunroof is that the system resonance occurs at a higher frequency, where the ears are more sensitive. It goes louder, but not as low. That particular trade off is present to some extent in every low frequency system.

iSurfSouthChinaSea
Posts: 17
Joined: Fri Apr 17, 2020 11:13 am
Location: Saint Petersburg, Florida

Re: 8" vs 10" truck Tuba

#78 Post by iSurfSouthChinaSea »

Seth wrote: Fri Dec 04, 2020 9:54 pm
Bill Fitzmaurice wrote: Fri Dec 04, 2020 5:08 pm
SethRocksYou wrote: Fri Dec 04, 2020 12:27 pm I don't know if having the driver in the mouth magically makes it a tapped horn or not
It doesn't. A tapped horn has no rear chamber. They're considerably more difficult to design than other horns, because of the phase relationships between the front and rear waves. Most of those that I've seen aren't very good. Danley's are very good, but they're the exception. BTW, Danley didn't make the first tapped horn, although he did coin the name. I've seen prior art in patents going back to 1958.
Another awesome little tidbit. Thanks Bill :thumbsup:
This is what I got so far. It’s just shy of 2’x3’ and with 9.5” internal height- just enough to accommodate the driver,
SB Acoustics SB23MFCL45-4. This is bigger than an 8. It’s a 4ohm rated for 150 watts RMS. Not sure where it will end up- kei van or living room. Note that this is the “tarted” version of the T-6. About to put the roof on. :noob:
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iSurfSouthChinaSea
Posts: 17
Joined: Fri Apr 17, 2020 11:13 am
Location: Saint Petersburg, Florida

Re: 8" vs 10" truck Tuba

#79 Post by iSurfSouthChinaSea »

Success. Much more linear than expected. Louder too so amp gain needs to come down.This amp has 32hz cutoff. Model shows a bump at 30hz, before it drops off like brick wall.

But I was going to swap the with the ACM 1.300, which will reduce power to 150 RMS @ 4 ohms, lower the cutoff filter to 24hz and allow a bass knob.

Or not. Maybe just put the in living room and use TAT.
This thing is taller but about same footprint.

The second photo shows the peculiar geometry of the tapped horn. No rear chamber. The literature says
it is a variant of the quarter wave resonator family.

I am going to coat it with duratex but I want to get
it tinted grey. I borrowed some white from a friend.
So I’m going to Sherwin Williams to get them to shoot it
with pigment. They don’t usually charge for this. Good company.
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