stay away from the table tuba

[shayneyasinski]

TOTAL JUNK!!!!!!!!!!!

built one up last night and for the 6 hours it took and the 2 sheets of wood it is crap.
my oldschool thinking of a big box with a good 15 in it is still the way to go.
this design (table tuba) is a 13 foot folded horn in a 30 inch square box.
so far with 1000 watts of carver power and a good 3 way xover i cant get it to do much other than cook the crappy 8 inch drivers it requires.
it plays low but not very loud.
I just fried the second driver trying to watch a movie and hear it in a setting it was designed for.
well lets just say that the dinosaur in the movie also crushed this crap box.
so next up i think is a 6 or 8 foot ported box with a good 15.

shayne

 

[highfihoney]

yup,big bass response require's big drivers,ive gave up on trying anything with bass drivers the size of a midrange.

 

[j_garcia]

To move air, you need surface area and cone excursion. To get truly low, most 8" drivers aren't going to get really low and still play loud. I believe you can buy SVS raw drivers and build your own cabinet. Do you have a subsonic filter? You're probably bottoming these 8" drivers feeding them stuff they really can't handle. The cabinet will never make up for what the driver is physically not capable of no matter what.

 

[Hi Ho]

I am sold on Ascendand Audio. I have one of their old models in my sub (Atlas 12") and it is amazing. I definetely suggest checking them out. I'm looking forward to the Alliance 18".

Is this "tuba" sub, by any chance, a Sonosub using Sonotube? What exactly did you build?

 

[shayneyasinski]

what i built

http://www.billfitzmaurice.com/plans/product_info.php/products_id/23?osCsid=081db6eb23cfac486040da38022c6c36


shayne

 

[jneutron]

Trashing the design is not the best place to start.

It may or may not have been your fault it didn't work as advertised. Perhaps something was overlooked.

TOTAL JUNK!!!!!!!!!!!

built one up last night and for the 6 hours it took and the 2 sheets of wood it is crap.
my oldschool thinking of a big box with a good 15 in it is still the way to go.
this design (table tuba) is a 13 foot folded horn in a 30 inch square box.
so far with 1000 watts of carver power and a good 3 way xover i cant get it to do much other than cook the crappy 8 inch drivers it requires.
it plays low but not very loud.
I just fried the second driver trying to watch a movie and hear it in a setting it was designed for.
well lets just say that the dinosaur in the movie also crushed this crap box.
so next up i think is a 6 or 8 foot ported box with a good 15.

shayne

Hmmm..
a thousand watts into an 8 incher. (are you nuts?)

Where did you cutoff the lows?
What was the driver?
Where did you place the enclosure?
How tight were the joints?

Although I can understand your frustration, I think it would be more worthwhile figuring out why your box didn't perform as you wished. Did you ask Bill about it?? I'd start there.

As a note: I built and ran 8 speakerlab "K's" running off of 8 SWTPC "tigersauraus" amplifiers back in '78 and '79. While not exactly portable, I used em for mobile apps.

Anyone who has built them knows that the really weird angle cuts are very very difficult to do..luckily, after cutting the parts for the first two, I learned from a very skilled carpenter and boatbuilder how to create fixturing to do the hard angles and still count to 10.

I found that if the cab had leaks, especially the back chamber, the driver excursion would enter the "lethal" zone, while the bass would suffer. Also, if I pushed power outside the cabinet working bandwidth, it was wasted as heat without sound.

If you use a 15 in a ported design, you will still have to worry about overexcursion. The signals to do this are certainly present on dvd's and cd's.

Cheers, John

 

[jeffsg4mac]

Hmmm, looking at their chart, it would appear that the response was something like -5db at 40hz and -10 or more at 30hz. Any good 8 in a vented or sealed box could do that. That is not impressive at all. I have built dual 8 2ways that were tuned to -3db at 35hz. Sure wish you would have posted that design here before you built it. Maybe some of us could have saved you some grief.

 

[SpkrBuilder]

If you're looking at the same chart as me , the output is only down 5 db relative to 100 Hz, and -10 db relative to 150-200 Hz. So if this used as a subwoofer used from 100 Hz down, -5 db at 30 Hz isn't too shabby. Please notice that the horn was was producing over 100 db at one watt of input? Assuming the the driver in the horn can handle 100 watts then the system can produce close to 120 db of output!

 

[SpkrBuilder]

Before destroying two drivers maybe it would have been prudent to determine why the audio level was lower than expected? Folded horn enclosures are complex and more difficult to build than bass reflex systems, maybe you overlooked something in the build that's causing you're enclosure to not work properly? How big is your room, where was the speaker placed in the room? With a properly designed folded horn a single 8" driver will put out as much bass as a 15" woofer in a ported box, it doesn't have move real far to produce a lot of sound due the acoustic impedance matching of the horn. Maybe the design is bad, but I would see if something else is amiss before trashing the design.

 

[Nestor]

TOTAL JUNK!!!!!!!!!!!

built one up last night and for the 6 hours it took and the 2 sheets of wood it is crap.
my oldschool thinking of a big box with a good 15 in it is still the way to go.
this design (table tuba) is a 13 foot folded horn in a 30 inch square box.
so far with 1000 watts of carver power and a good 3 way xover i cant get it to do much other than cook the crappy 8 inch drivers it requires.
it plays low but not very loud.
I just fried the second driver trying to watch a movie and hear it in a setting it was designed for.
well lets just say that the dinosaur in the movie also crushed this crap box.
so next up i think is a 6 or 8 foot ported box with a good 15.

shayne

Did you do the required leak check as per the plans?

Also, where are you placing it? Horns work best firing into a corner.

Why didn't you just build the THT?

Did you post on Bill's forum? There are many helpful members there, and Bill is quite prompt in replying.

 

[Adam]

Just an FYI...the OP hasn't been back since 13 minutes after his/her last post...8.5 years ago. I doubt that person is going to be answering questions.

 

[Bryceo]

Just an FYI...the OP hasn't been back since 13 minutes after his/her last post...8.5 years ago. I doubt that person is going to be answering questions.

Are you sure?


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