Super THT build thread - Page 2

Looking GREAT man!

Keep at it!


dbl

Looks good.

Question for yeah.

Are you using PL? If so, are you spreading it or touching it once it's been applied?

SuperE,

I wouldn't worry about the access panel cuts like people are stressing about. I cut mine out freehand with a jigsaw AFTER I had built the horn. I went back after the horn was built and cut it out and cleaned up the cut with a flush-cutting bit. I then made a new access panel that fit perfectly, with rounded edges to match the clean-up cuts the router did... No worries, I'd trust the guy you are working with, this is probably not his first rodeo....

The Oaudio 300W amp will not let the THT flex it's true potential. It has a highpass filter at 20Hz, not adjustable. The 500W version has not only a selectable HP filter/boost, but a one band parametric EQ as well.

The 30" version should give you some more output, can't wait to hear what you think about it.

About the cats...they for some reason LOVE MDF. My TT was made of MDF, and they would stay inside it for hours, where I couldn't see them past the first corner. My nightmare was that one would get stuck inside and I'd have to take the damned thing apart to get the cat....so I made a grill for the TT. I haven't made a grill for the THT (much more room to turn around in it than the TT, and they don't spend near as much time in it, no MDF), but I have caught them inside (unbeknownst to me) and have seen them bolt out when an opening scene in a blu ray turns on the sub....

Strangely enough, sometimes they'll GET IN THE HORN while it's playing, usually background music at a low level...

JSS

Okay. That's what I thought. For the external panels that have squeeze out, just leave it and let it dry. It's actually quite easy to remove with a sharp chisel after it drys in one piece versus trying to get it off after you smudge it. Someone gave me this tip early in my build. It saved me hours of work.

You're making great progress.

The Dayton DVC will take almost 200 watts with no filtering without reaching xmax. That should be sufficient.

Use Room EQ Wizard, with a Galaxy or RS SPL meter. Use the spectrum function, and don't let THD reach above 10%, equivalent to Xmax, and no harm will ever come to your driver.

If no measurements are to be taken, use the Incredible Hulk Sonic Cannon Scene (attached), it's what I have used.

Move the subsonic filter down a notch and move the volume up a few dB every time you play the scene. When it sounds weird, stop....done...you will know. For all the ******** people say about not hearing distortion at low freq, trust me, you will....it will make you think twice about CEDIA standards.

JSS

Well, I guess that does it for me. EP2500 here I come.

If you use the EP, things to consider using are the Reckhorn B2 or the eQ.2 by elemental designs, if you will be playing at high levels, just in case distortion creeps into the lowest freqs...you may not need this, though.

The reason I use the Reckhorn is the steeper highpass. The eQ.2 has a 12dB/oct slope, vs the 24dB/oct slop on the Reckhorn.

The eQ.2 can boost down to 10Hz though (to flatten THT response), and highpass down to 5Hz, so it depends on what you need. I needed the steep highpass more than anything due to my situation with Audyssey and the Oaudio amp.

JSS

Are those the same thing as a Behringer Feedback Destroyer Pro DSP1124P ???

Honestly, what's the problem with just using the EP2500 by itself?

Nothing. The 2 options above would help boost the sub-20Hz response so you can be flat to a lower freq, depending on room gain.

JSS

I gotcha.. Thanks.

Do you happen to know if the Yamaha P2500S amp would be decent?

Crown Xti 1000. The built in DSP would have sold on its own for more than the entire amp ten years ago. Best price at Northern Sound.

Yamaha makes a good amp. This one has a variable speed fan controller too.

I would strongly recommend against this amp--epic failure in tests here

http://www.avsforum.com/avs-vb/showt...6#post13869426


http://www.avsforum.com/avs-vb/showt...4#post13877614

First gen reliability problems have been fixed. The Xti are highly rated by many of my forum members who have them, and that's in pro-sound applications far more stressful than home, including being transported regularly. But of course they only use them with horn loaded systems.

The yamaha has a variable subsonic filter, and it only goes down to 25Hz. Is this a bad thing with a THT?

Has anyone actually tested it?



Check that same thread I linked above--see the first page for amps tested--I think there were issues with the Dayton 1000 as well.

That's the old, discontinued model, the SA1000 replaced it which is probably what I'm going to go with eventually. Right now my Behringer A500 will have to do.

http://www.parts-express.com/pe/show...number=300-811

I wonder if they use them for anything below 20Hz.

The biggest problem we saw in the tests is with the < 20Hz stuff.

Im pretty sure they are great from 30Hz on up and the DSP is pretty cool to have for even active mains.

You can disable it if needed.

So long as it can be switched out it's OK. For maximum output a 25 Hz filter is required, but with up to 200 watts no filter is required, and most users will find even 100 watts to be almost unbearable. And if they don't the neighbors probably will. Think angry villagers with torches and pitchforks in hand.
I can see that being a problem with direct radiators. For the intent of this particular thread, who cares?

Quick qualifier, folks...

I only put forth the options I have because you can squeeze out more juice out of the THT with some boosting below 25Hz, and you may have low freq boost problems running Audyssey, in which case you need a steep high-pass. If you have good to great room gain, you will not need this boosting, and an amp like the A500 will be great, and IIRC, the A500 measured very well in tests (not sure it was this forum, though).

JSS