Table Tuba build!!

[digital_chris]

Nope, I won't be looking down the throat of it. It will be used as a table and placed as per instructions (corner of the room, mouth facing the wall). Speaking of the Foster amp, they offer 2 now, one with the 30hz filter and now one with a flatter 20hz filter. I know the cabin is only tuned for 30hz, but would it hurt to get the 20hz or should I be safe and stick with the 30?

[Drey Chennells]

Nope, I won't be looking down the throat of it. It will be used as a table and placed as per instructions (corner of the room, mouth facing the wall). Speaking of the Foster amp, they offer 2 now, one with the 30hz filter and now one with a flatter 20hz filter. I know the cabin is only tuned for 30hz, but would it hurt to get the 20hz or should I be safe and stick with the 30?

I'd recommend you go with the 30. Its your choice of course whether extension or output level is more important.

i love this

The amp supposedly puts out 1000w x 2 in 4 ohms, who knows what that translates to RMS, either way I figured it would be enough for this driver. But, all I did before firing the cab up was change my mains to small, turn subwoofer on and set freq to 80hz. Is there something I'm missing?

yeah. a real power supply, output transistors,etc.. sorry it's only giving you 8volts!?

[DJPhatman]

Speaking of the Foster amp, they offer 2 now, one with the 30hz filter and now one with a flatter 20hz filter. I know the cabin is only tuned for 30hz, but would it hurt to get the 20hz or should I be safe and stick with the 30?

Stick with the 30Hz for the TT. If you think you need below 30Hz, then you need a THT.

[Radian]

Shouldn't he be going with a 20Hz high pass instead? The TT Fc is 22Hz and his cab is 18" wide with the classic 10". I think he'd be neutering performance quite a bit with a 30Hz HP.

[digital_chris]

Shouldn't he be going with a 20Hz high pass instead? The TT Fc is 22Hz and his cab is 18" wide with the classic 10". I think he'd be neutering performance quite a bit with a 30Hz HP.

It's only the Dayton 8", not the ten. If I won't hear/feel anything below 30hz with that cab, I guess I'll stick with the 30hz filter.

Thanks for the suggestions, as I said, my amp SUCKS I know, just thought I could use it since the TT doesn't require loads of power. Oh well, I tried and I failed

[DJPhatman]

The 30Hz high pass built into the amp is not terribly steep, 12-18dB/Octave, IIRC. You will get the sub-30Hz material, just at a reduced level to prevent passing Xlim. For home use, this shallow slope is of no consequence.

[digital_chris]

Ahh, that makes sense. I wasn't sure if it was a sharp cutoff or not, I'm not too familiar with crossovers

[digital_chris]

Alright, it's time for update since it's been a little while. I still haven't gotten my Foster amp yet (it's in the mail) but I temporarily hooked up my old Pyle PA amp. I put the sub in the corner and hooked it up, went into Audyssey and set my mains to small and sub on with a 80hz cross over. I then grabbed my R-Shack meter, went to the test tones section and adjusted the subwoofer db output to match the mains db output. Then I played a couple movies. From initial setup, the bass was nice and strong but very noticeable that it was in the corner I then had a buddy over and we moved it around the room and found that the original corner was best but I hated that I could point out the cab.

Today comes and I decide to run Audyssey. It setup my speakers much differently that I had originally. They set my fronts to large, crossover to 60hz and bass to "Mix". They also set my subwoofer distance to about 15 feet, when the cab is only 8-10 feet from the furthest seating distance, hmm. Anyway, the LFE content was much more toned down but blended in the room much better and the subwoofer isn't nearly as noticeable, I'm happy about that. The only thing I am still worried about is pushing the woofers in my mains to hard. I few scenes in I, Robot made the cones move quite a bit, I can't tell if it's close to x-max or not.

So, do you guys think I should leave the Audyssey settings as is or would you tweak any of them from what I've described?

[AntonZ]

Today comes and I decide to run Audyssey. It setup my speakers much differently that I had originally. They set my fronts to large, crossover to 60hz and bass to "Mix". They also set my subwoofer distance to about 15 feet, when the cab is only 8-10 feet from the furthest seating distance, hmm.

The TT horn path is some 7 or 8 feet long, if you add that to the distance of 8-10 feet you end up with around 15 feet. Audissey is probably quite right with about 15 feet.

Don't know about the other stuff, not enough into HT setup and sub bass.

[Bill Fitzmaurice]

From initial setup, the bass was nice and strong but very noticeable that it was in the corner

If you can directionally locate the cab the crossover frequency is too high and/or filter slope insufficient.

The only thing I am still worried about is pushing the woofers in my mains to hard. I few scenes in I, Robot made the cones move quite a bit, I can't tell if it's close to x-max or not.

If you're pushing the cab hard a 30Hz high pass filter would be in order. Peak to peak capability of the driver is over a half inch, which is a lot.

[Radian]

So, do you guys think I should leave the Audyssey settings as is or would you tweak any of them from what I've described?

No. I would certainly tweak them from what's described. But you're missing the key ingredient. That plate amp.

I recommend sitting tight until it arrives. The system really needs the Low Pass filter in the plate amp to sound right.

When the plate amp does arrive. Set your receiver back these settings as a starting point:

Mains - Small

Crossover Frequency - 80Hz

Set the gain or volume knob on the plate amp somewhere's around 3/4.

Play an 80 Hz test tone through the system and have someone flip the phase switch back and forth on the plate amp while you listen at your designated sweet spot. One setting should be louder than the other. Keep it set at the louder position.

Run the Audyssey correction software.


Setting your mains to "small" doesn't mean you have "small" speakers at all. It's an easily misinterpreted way, IMO, of declaring that you'd like the receiver to High Pass the signal going to the mains at your desired crossover point. For example, my mains are two 125 lb 2'X2'X3' horns, but I still have to have the receiver set to "small" to get the system to function correctly with a separate sub.

[psg]

Well, finally finished!!! Check out the pics...

So it looks exactly like a Tuba HT except smaller?

[Bill Fitzmaurice]

Well, finally finished!!! Check out the pics...

So it looks exactly like a Tuba HT except smaller?

Completely different.

[psg]

Well, finally finished!!! Check out the pics...

So it looks exactly like a Tuba HT except smaller?

Completely different.

Okay, but it looks the same on the pictures at the end of page 2. I mistook it for a Tuba HT...

[digital_chris]

Duplicate...