Hello From Touchet WA

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Drake
Posts: 24
Joined: Thu Dec 21, 2017 1:26 pm

Hello From Touchet WA

#1 Post by Drake » Thu Dec 21, 2017 7:43 pm

I'm new to the speaker building world. I have purchased a few books on speaker design and building, and learned a bit about designing and building sealed boxes, ported boxes, boxes with passive radiators, transmission line speakers. Surprisingly the books did not discuss horns. Well, I have a woofer in my car, a sealed box with two 12s and 400 watts of power. Worked great. But then I got married and my wife started putting groceries in the trunk, right up against the drivers. Kept telling her not to do that and she ignored me. Well, now the foam surrounding the drivers have all deteriorated, the drivers themselves have dents and holes, and of course my bass is a fraction of what it used to be. So I got online and started searching around for something that would have the speaker completely inside the box. Somehow I found Bill Fitzmaurice and discovered the Tuba 18. Figured it would work great in the car! Also, figured I could use it in my small home theater system. I also saw that I would like to build some other speakers as well, the line arrays for the home theater mains and center channels. And of course eventually the Tuba HT. So I went ahead and ordered the CD of all the speaker designs, emailed bill and had him send me the Tuba 18 plans via email, purchased the baltic birch as well as the tang band 8 inch driver. I've got nearly all the pieces cut out and the driver is arriving today. Definitely excited to hear what this speaker will do in the car.

One of my acquaintances, who has built and sold over 500 speakers for large venues and bars and such, commented that horns have great sustained bass notes but lack the punch. He also insists that the sound doesn't fully develop until 20 or 30 feet away from the speaker. When I asked him if it was due to reflections off walls cancelling out the speaker sound in certain areas, he insisted that the same phenomenon occurred in the great out of doors with no walls nearby. So I'm wondering, what is it exactly that gives speakers good punch? Something that can pound real good? Obviously plenty of power, and good light speakers that have a fast response. From that aspect, bridging a single 8 inch speaker across my 2 channel 400 watt amp should do the trick. Of course I imagine that 400 watts is rated as peak power. Not all of what my friend has told me makes sense to me (I'm a mechanical engineer and can't understand the physical laws that would account for what he was saying). So will the tuba 18 with the tang band 8 inch driver provide good punch as well in addition to the deep sustained bass for audio tracks in the car and my home theater?

CoronaOperator
Posts: 1648
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: Hello From Touchet WA

#2 Post by CoronaOperator » Thu Dec 21, 2017 9:26 pm

Drake wrote:
Thu Dec 21, 2017 7:43 pm
, commented that horns have great sustained bass notes but lack the punch. He also insists that the sound doesn't fully develop until 20 or 30 feet away from the speaker.
Hi Drake, welcome to the forum!

Horns and Direct Radiating subwoofers definitely sound different. In a Direct Radiating sub, you are not only hearing the fundamental notes being played but also a lot of harmonics are also present. So if you play a 60hz tone, you are also hearing 120hz, 180 hz, 240hz, etc overtones. Since our ears are more sensitive to these higher frequencies than the lower ones it sounds more punchy. All these overtones are of course distortion in that the are not present in the original signal.

Horns on the other hand are bandpass devices so they filter out all those harmonic overtones leaving you with super clean bass with THD below audible levels. That is why your friend says they are good for sustained notes as they sound so clean compared to a direct radiating sub, yet lack punch as those harmonics are missing.

It takes a day or two to get used to the clean sound of a horn but once you do you won't ever go back.

My horns sound awesome standing right next to them, the 20-30 feet away thing must be because they don't sound so abrasively loud right next to them like a direct radiator because of the lack of harmonics where our ears are more sensitive. You also don't get the rush of air up close from the ports like in a bass reflex design.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

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Bill Fitzmaurice
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Re: Hello From Touchet WA

#3 Post by Bill Fitzmaurice » Thu Dec 21, 2017 10:17 pm

Drake wrote:
Thu Dec 21, 2017 7:43 pm
One of my acquaintances, who has built and sold over 500 speakers for large venues and bars and such, commented that horns have great sustained bass notes but lack the punch. He also insists that the sound doesn't fully develop until 20 or 30 feet away from the speaker.
Your friend may mean well, but he doesn't know what he's talking about. Not that he's alone, because he's repeating the myth of wave propagation, and it wouldn't have a name if there weren't lots of people who believe it. But none of them are acoustical engineers. As for punch, that's what the uninformed call high level harmonic distortion. He's correct that bass horns don't have high level harmonic distortion, but that's a good thing. It does, however, take some getting used to hearing what you're supposed to be hearing.

viewtopic.php?f=10&t=999

Drake
Posts: 24
Joined: Thu Dec 21, 2017 1:26 pm

Re: Hello From Touchet WA

#4 Post by Drake » Thu Dec 21, 2017 11:17 pm

Nice. The myth of wave propagation. Well now I at least have a name for it.

I never realized that punchy sound was from high level distortion of the speaker cone. But it does make sense! I was thinking along the lines of how quickly the system has to react to an impulse and if the transient response was too slow then you won't have the punch. Now I'm really looking forward to getting the Tuba 18 done! Can't wait to hear it!

Drake
Posts: 24
Joined: Thu Dec 21, 2017 1:26 pm

Re: Hello From Touchet WA

#5 Post by Drake » Fri Dec 22, 2017 12:25 am

So the Tang Band 8 inch driver arrived today. Eagerly opened it up to see what it looks like. Here it is.

https://photos.app.goo.gl/Q0EU4EbwXVREpfRO2

Notice the dent in the cover on the cone... is that a cause for concern? Any way to get it to pop back out? Should I send it back and get a new one? Or will it not make any difference?

Thanks

- Rick

CoronaOperator
Posts: 1648
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: Hello From Touchet WA

#6 Post by CoronaOperator » Fri Dec 22, 2017 1:55 am

Drake wrote:
Thu Dec 21, 2017 11:17 pm
I was thinking along the lines of how quickly the system has to react to an impulse and if the transient response was too slow then you won't have the punch.
Where you are going with impulse I would define as "impact" rather than punch. Where impact is concerned, horns rule that roost as well although for good impact you also need tops that can play their part as well.

As for your driver, place a vacuum nozzle (turned off) over the dent. Then quickly turn it on and off a few times to pop it out. You could send it back but the damage on a sub is mostly cosmetic.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

Grant Bunter
Posts: 6585
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Hello From Touchet WA

#7 Post by Grant Bunter » Fri Dec 22, 2017 3:07 am

Hi Drake,
Welcome to the forum! :)
Drake wrote:
Thu Dec 21, 2017 7:43 pm
Somehow I found Bill Fitzmaurice and discovered the Tuba 18. Figured it would work great in the car! Also, figured I could use it in my small home theater system. I also saw that I would like to build some other speakers as well, the line arrays for the home theater mains and center channels. And of course eventually the Tuba HT. So I went ahead and ordered the CD of all the speaker designs, emailed bill and had him send me the Tuba 18 plans via email, purchased the baltic birch as well as the tang band 8 inch driver. I've got nearly all the pieces cut out and the driver is arriving today. Definitely excited to hear what this speaker will do in the car.

So will the tuba 18 with the tang band 8 inch driver provide good punch as well in addition to the deep sustained bass for audio tracks in the car and my home theater?
Before you get much further, I'll throw in a curve ball.
Build an Autotuba for your car instead.

You have a down the track plan to build an table tuba for HT, the auto tuba could cover that until it's built.
Except after you hear the auto tuba (which is an auto design) in your car, it won't ever get out of the car.

The T18 is a nice design, but as a single in a small room, for HT, it's barely enough.
It's also not a auto design, so, as a short term dual use sub, it won't do either auto or HT as well as specific designs for specific purposes.

Throw in cabin gain, and an AT will shake your mirrors and give you down low astounding bass in vehicle, with not a lot of power...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

Drake
Posts: 24
Joined: Thu Dec 21, 2017 1:26 pm

Re: Hello From Touchet WA

#8 Post by Drake » Fri Dec 22, 2017 10:29 pm

As for your driver, place a vacuum nozzle (turned off) over the dent. Then quickly turn it on and off a few times to pop it out. You could send it back but the damage on a sub is mostly cosmetic.
I tried that this evening with a shop vac and unfortunately it didn't pop out. I also tried denting in the areas around and then pulled it out with the vacuum but it only went back to what it was. So no luck. I'm leaning towards sending it back for a replacement. Unless of course it is only cosmetic. Will that dent cause distortion in the cone of the woofer?
The T18 is a nice design, but as a single in a small room, for HT, it's barely enough.
It's also not a auto design, so, as a short term dual use sub, it won't do either auto or HT as well as specific designs for specific purposes.

Throw in cabin gain, and an AT will shake your mirrors and give you down low astounding bass in vehicle, with not a lot of power...
My current system is comprised of a polk audio psw12 and 2 monitor 20 speakers. The amp in the psw12 is starting to fail. I was thinking that the tuba 18 would fit as a replacement of the psw12 until I get the full ht system built. And do double duty in the car, as it is smaller and leaves more trunk space. But I may end up as the proud owner of the auto tuba as well 😉 Was also thinking that if the tuba 18 goes well with the monitor 20s that I may replace my wife's system in the kitchen with this setup.

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