[Bbieger]

Finished my 21" wide THT over the weekend. Dayton DVC and 240 plate amp. Fired it up and it definitely has lots of output but it doesn't seem to be as detailed as my SVS NSD. Has anyone else noticed this phenom?


I didn't play too much with placement issues so there is that but does this design NEED to be corner loaded? I have a somewhat challenging placement as I have limited room behind my screen. Its going to have to be placed around 3' from the corner that has full bass traps.


any ideas?

 

[darkhorror]

have you checked both subs with an SPL meter with something like REW? I don't know if it should be more detailed or not but a lot of times you are hearing whats going on with your room placement. A bump or low at certain freq can cause subs to sound less or more detailed.


I have been having a problem with a single sub that I have right now. Depending on placement it sounds very musical other places not so much. Problem I am having is that the place it sounds very musical it's response drops off very sharply below 40hz till about 20hz. But above 40hz I get very flat response. I have found one place that gives me response to 34 hz before the sharp drop till about 20hz but above 40hz response is all over the place. So I am going to continue to test till I can get the response I should be getting.

 

[Bbieger]

I haven't run any sweeps as I haven't installed the carpeting or door or any acoustic panels so I figured it would be a waste of time at this point.


Any problems with running the SVS and the THT? I thought I read that this can cause problems (two different sub types) but I figure if it sounds good then.... why not?

 

[jpmst3]

Integrating the two types can be problematic.


Try it and see how it goes.

As they say, you don't know 'til you try.

Horns have significantly more delay and then there are group delay issues with each alignment, etc...not to mention freq response curves...

 

[Th3_uN1Qu3]

What sounds good to you is what matters. As long as you find the right spots to place the subs so you don't get cancellation, it'll be just fine.

 

[Bbieger]

Fair enough. Are their any guidelines when placing two subs in a room? My room is 10.5 x 26. The tht is going behind my false wall in front cause it's huge and ugly. It would be nice to run RCA cable before I install carpet.


I figure I can deal with distance (timing) issues with the reciever settings.

 

[jpmst3]



Quote:
Originally Posted by Bbieger /forum/post/18142851



I figure I can deal with distance (timing) issues with the reciever settings.

That's where the problems often lie.

You can only adjust the delay for one sub. If you connect two or more, you cannot effectively fix the delay issues.


You need a BFD or DEQ or DCX to fix the delays...

 

[CZ Eddie]



Quote:
Originally Posted by jpmst3 /forum/post/18142904


If you connect two or more, you cannot effectively fix the delay issues.

Unless both subs are of equal distance from the listening position, I would assume?

 

[RobG5589]

I recall reading that the THT does not play well with others. Also, the folds in the THT add something like 15 feet to the distance settings. Something I just learned myself.

 

[dbldare]

As for the low end extension, you built the 21" version. You'll lose some of the lower end frequencies with the smaller box.



dbl

 

[Kanaris]

One thing you guys have to make sure is that the driver is sealed properly against it's plywood base... tighten it and go back after a few hours and tighten it again.... flip it with your finger and it should make a nice tight sounding thump if it sounds hollow it could be leaking at the base.

 

[Bill Fitzmaurice]



Quote:
Originally Posted by dbldare /forum/post/18143453


As for the low end extension, you built the 21" version. You'll lose some of the lower end frequencies with the smaller box.

True, but not that much.

Quote:
it doesn't seem to be as detailed as my SVS NSD.

What you're referring to as 'detailed' may well be above bandwidth harmonics, which direct radiators create in spades. I suspect you've got quite a bit of that going on if you use bass traps, which don't actually do all that much below 80 Hz but are very useful in soaking up excess midbass. It's not unusual for new folded horn owners to miss those harmonics, which folded horns do not create.

 

[jpmst3]



Quote:
Originally Posted by CZ Eddie /forum/post/18143155


Unless both subs are of equal distance from the listening position, I would assume?

No, the THT will have a built in delay as the wave has to propagate the horn path. The direct radiating design will have less delay...

 

[kryptonitewhite]

LonelyRaven went through this in the opposite direction... "The Wicked One" to 21" sealed. He missed his horn coloration.

 

[CZ Eddie]



Quote:
Originally Posted by jpmst3 /forum/post/18143664


No, the THT will have a built in delay as the wave has to propagate the horn path. The direct radiating design will have less delay...

Right, I missed the part where he said he was going to run the SVS with the THT. I assumed the discussion was leading towards running a pair of THT.

 

[amik]



Quote:
Originally Posted by Bbieger /forum/post/18142851


Fair enough. Are their any guidelines when placing two subs in a room? My room is 10.5 x 26. The tht is going behind my false wall in front cause it's huge and ugly. It would be nice to run RCA cable before I install carpet.

You have to measure and see what you've got. Trying to guess placement is asking for trouble because even though you know dimensions you don't know what impacts different materials might be having (cinder block behind the studs is a lot different than another open space behind the studs).


Floyd Toole has a chapter on this issue in his book where one of the recommendations is to try two mid-wall location opposite one another.


I've got three subwoofers in my room, two in the ceiling at roughly mid-wall locations and one on the floor in a corner. My room also has big openings to an entryway, the kitchen and then french doors to a deck, so it's not exactly a simple rectangular space. It took a lot of measuring and tweaking to get right.

 

[lennon_68]

In all of the similar threads the problem ended up being calibration-related, so you may want to double check the settings on your AVR. Specifically: Does your AVR have Audyssey or something similar? If so - did you re-run it after changing subs? what level did it set the LFE trim at? give it a try with the auto-cal EQ turned off just for kicks. What XO are you using? Are the mains set to "double bass" or something similar where the subs and front L&R are both producing the LFE signal? What is the XO filter set to on the plate amp of the THT?