THT initial impression disappointing?

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mastertee31
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THT initial impression disappointing?

#1 Post by mastertee31 »

So I finally banged out 1 of 2 THT original plans 2+ years in the making while collecting dust. Baltic Birch, PL, Dayton RSS, roughly 36x36x36”. Powered by a crown power amp. I fired it up briefly today low passed at 80hz and hooked up 1 tower speaker to hear what was going on. It’s not in its final resting place nor has it been tuned at all. Output is incredible no doubt but I find the bass to be sloppy, not quick at all...

Anyone else have the same feelings? I’m sure after having it eq’d and time aligned it will sound better? For those of you that have built these how much eq do they require? Should I let my home theater processor handle it or throw a minidsp with Dirac into the mix? I guess my question is how much work do these require to sound good?

Side note? Bandpass this thing yay or nay? (What frequencies) also, what tone to play while adjusting gain for max voltage without damaging woofer? (What voltage for this driver?)

Sorry for the questions it’s been more than 2 years since I started this project and don’t remember all the ins and outs.

Thanks

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Seth
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Re: THT initial impression disappointing?

#2 Post by Seth »

What were your test conditions? Size of room, sub placement in the room, what sort of listening material were you using? Did you use a piece of tubing to check for leaks before attaching the access cover?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Bill Fitzmaurice
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Re: THT initial impression disappointing?

#3 Post by Bill Fitzmaurice »

There's no such thing as quick or fast or sloppy bass. Anything that might be called quick or fast doesn't occur in the lows, it occurs in the mids. When the bass is perceived to lack definition it's usually because it's too loud, drowning out the mids where definition resides.

mastertee31
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Re: THT initial impression disappointing?

#4 Post by mastertee31 »

Test conditions: fired into corner of room, 8’ ceiling, 16’ x 23’. Room treatment, Apple Music from my MacBook Pro through an arcam Dac and a couple of clips from movies on Prime video and Netflix. Have not checked for leaks but can if necessary (I’d be extremely surprised if there were leaks with the amount of PL I used)

There are definite time alignment issues...

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Seth
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Re: THT initial impression disappointing?

#5 Post by Seth »

mastertee31 wrote: Mon Feb 15, 2021 1:40 pm Test conditions: fired into corner of room, 8’ ceiling, 16’ x 23’. Room treatment, Apple Music from my MacBook Pro through an arcam Dac and a couple of clips from movies on Prime video and Netflix. Have not checked for leaks but can if necessary (I’d be extremely surprised if there were leaks with the amount of PL I used)

There are definite time alignment issues...
Sounds like your set-up is good. Checking for leaks is part of the assembly instructions in the plans and worth doing. On a T39 I built, all the joints were just fine, but I had a leak around the driver. It wasn't the case for my problem, but many drivers use a multi piece gasket and have small leaks where those pieces fit together.
Image
If your driver has this sort of gasket, do your best to test the full circumference of the driver for any trace of a leak. If you detect a leak, a light film of silicone where the gasket pieces meet usually solves it.

Ultimately, I think Bill hit the nail on the head though. Sounds like your room/set-up/placement is appropriate and I don't think a leak would cause the sound experience you described. I think you'll be very pleased once all the levels are properly set. Still, it's worth checking for leaks too.

I'm not really a home theater guy... Someone else will have to speak to the EQ, bandpass, and limiter questions.

Good luck with the remainder of the project! :thumbsup:
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Radian
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Re: THT initial impression disappointing?

#6 Post by Radian »

mastertee31 wrote: Sun Feb 14, 2021 8:23 pm I fired it up briefly today low passed at 80hz and hooked up 1 tower speaker to hear what was going on.
Too high. Set it lower, otherwise the rising response will be walking all over the rest of the system. Try somewhere's between 40-60 Hz, and make sure that tower speaker gets high-passed at 80 or higher.
Good food, good people, good times.

4 - AT
1 - TT
1 - THT Slim
2 - SLA Pro 4x6 Alphalite

mastertee31
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Joined: Mon Dec 08, 2008 9:06 pm

Re: THT initial impression disappointing?

#7 Post by mastertee31 »

Seth wrote: Mon Feb 15, 2021 2:19 pm
mastertee31 wrote: Mon Feb 15, 2021 1:40 pm Test conditions: fired into corner of room, 8’ ceiling, 16’ x 23’. Room treatment, Apple Music from my MacBook Pro through an arcam Dac and a couple of clips from movies on Prime video and Netflix. Have not checked for leaks but can if necessary (I’d be extremely surprised if there were leaks with the amount of PL I used)

There are definite time alignment issues...
Sounds like your set-up is good. Checking for leaks is part of the assembly instructions in the plans and worth doing. On a T39 I built, all the joints were just fine, but I had a leak around the driver. It wasn't the case for my problem, but many drivers use a multi piece gasket and have small leaks where those pieces fit together.
Image
If your driver has this sort of gasket, do your best to test the full circumference of the driver for any trace of a leak. If you detect a leak, a light film of silicone where the gasket pieces meet usually solves it.

Ultimately, I think Bill hit the nail on the head though. Sounds like your room/set-up/placement is appropriate and I don't think a leak would cause the sound experience you described. I think you'll be very pleased once all the levels are properly set. Still, it's worth checking for leaks too.

I'm not really a home theater guy... Someone else will have to speak to the EQ, bandpass, and limiter questions.

Good luck with the remainder of the project! :thumbsup:
Just a follow up, pretty sure the gasket is multi piece. When installing the driver I applied a layer of latex caulk completely around the driver and even sealed the mounting screw holes. I had heard a while back that silicone is not a great choice for sealing drivers as the offgas from the silicone drying can eat the surrounds on some drivers.

mastertee31
Posts: 36
Joined: Mon Dec 08, 2008 9:06 pm

Re: THT initial impression disappointing?

#8 Post by mastertee31 »

Radian wrote: Mon Feb 15, 2021 6:29 pm
mastertee31 wrote: Sun Feb 14, 2021 8:23 pm I fired it up briefly today low passed at 80hz and hooked up 1 tower speaker to hear what was going on.
Too high. Set it lower, otherwise the rising response will be walking all over the rest of the system. Try somewhere's between 40-60 Hz, and make sure that tower speaker gets high-passed at 80 or higher.
Will give this a shot. Currently the other half of the basement is being renovated. Turning the theater room into storage. Hoping to get this up and running in it’s final resting place soon. Unfortunately while building this room a bulkhead had to be built to house the projector screen, I had done calculations that I needed a 5’ depth. A friend who was helping at the time convinced me that 4’ would be plenty... now the screen doesn’t drop without hitting the top of the THT. Hoping laying it on its side a v-coupling with the other one solves this problem, otherwise I might have to sell them eek?!

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Bill Fitzmaurice
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Re: THT initial impression disappointing?

#9 Post by Bill Fitzmaurice »

Placing subs side by side in a HT seldom works well, as they'll both excite the same room modes and boundary cancellations. One in the front of the room and one in the back usually works better.

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