4 THT's

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Old Mike
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Joined: Thu Sep 13, 2012 12:27 pm

Re: 4 THT's

#31 Post by Old Mike »

Quick update,

Delayed by rain and believe it or not SNOW!!!. Disadvantage of a northern climate. Normal temps for this time are about 18 Centigrade but it dipped pretty low a few days ago. I have to push the aircraft out to be able to work on the speakers so had a four day period that I couldn't do that, days that I had free of course.

I now have 3 units ready for paint and the 4th unit was closed up today. Two more days of construction and I will be painting. If I don't paint them before moving them into the house it would never happen.

Drive units are being run in and should be finished before the cabinets are ready to receive them. People have been lined up to help me move them into the theater, starting to see the finish line.

88h88
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Location: Coventry, UK

Re: 4 THT's

#32 Post by 88h88 »

Old Mike wrote:If I don't paint them before moving them into the house it would never happen.
This is how I have a table tuba in my living room without a paintjob. :lol:
4xOT12s, 2xT39s@22", TTLS@18", 2xT60@18"

Old Mike
Posts: 24
Joined: Thu Sep 13, 2012 12:27 pm

Re: 4 THT's

#33 Post by Old Mike »

Progress has been made. Drivers installed, polarity and leak checked, buttoned up and ready for the move to the theater room. Hoping to get my "hired muscles" around this weekend for the move. Mechanical knees and shoulder surgeries over the years have limited my lifting ability, ten years ago I could have wrangled these monsters myself, alas old man time has done his work on my body.

I've attached some photos below. I scarfed jointed the seal on the face of the driver and also on the cabinet and I also used a piece of thin wall brass tubing to punch holes in the seal on the drivers so the screws would not tear the rubber. There were no leaks at all on either the driver seal or cabinet seal, a quick test at 50 Hz had my shop resonating!!!! I used a number 60 drill bit to put a pressure equalization hole in the cabinet near the connectors.

One change in plans. I was going to use my calibrated microphone and use my DSP 8x10 to arrive at a flat response out side the house. Decided not to bother, I'm just going to let the EQ system of my Lexicon MC12 HD tune the THT's to the room after install. No point in shaping to a flat response outside the room and then EQ for room modes, it could well be that I'd end up applying a lift in response at one frequency in the open only to have the room EQ reverse that action.

Hoping my muscle makes it here tomorrow. Really want to here these monsters in action, I'm calling them "the four horsemen of the apocalypse".
Attachments
leak test.jpg
punch.jpg
scarfe.jpg

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Radian
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Joined: Tue Jul 29, 2008 12:56 pm
Location: Tucson, AZ

Re: 4 THT's

#34 Post by Radian »

Old Mike wrote: a quick test at 50 Hz had my shop resonating!!!!
Try 20V at 15 Hz. :wink: :wink:
Good food, good people, good times.

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

Old Mike
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Joined: Thu Sep 13, 2012 12:27 pm

Re: 4 THT's

#35 Post by Old Mike »

They are in place and working.

Some shots below of moving day, I used my tractor to carry them to the house, I let my son and neighbor do the hauling down the basement stairs.

You can see from one of the shots that the THT's are placed in the room corners with the throat firing into the room. I had spent a lot of time with the 8 twelve inch sealed box subs previously and had found that for my room that positioning gave me the overall smoothest response. I don't need the gain that would come from firing the units into the corner itself. (Four of these in the room could take the walls out if I wanted to).

For me it has all been about getting the least variation across all the seating positions and getting the lowest distortion performance and not insane bass to rattle my teeth. These units are just loafing in this application, barely breathing.

I used my Lexicon MC12HDEQ to tune them to the room and the results are fantastic. I can't show any "numbers" as the Lexicon doesn't display what correction it has applied. The THT's are being used on the LFE channel. For music my mains go down to 20 HZ and have sufficient capability to handle any music, despite being dipoles and the inherent excursion for the bass drivers. Movie sound tracks are a different story however and so when watching movies the mains are cut at 40 or 50Hz and anything below that frequency is transferred to the LFE channel.

The performance of the THT's is fantastic, it has exceeded my expectations, the sealed subs were not exactly shabby but the THT's go deeper and audibly have much lower distortion than the sealed subs. They also integrate better with the mains. I'm very happy with the results.

The acid test, and this has been quoted so many times by so many men, my wife, unsolicited said, "I can ear the bass better, it's cleaner". She is a Jazz Saxophonist and has played in big bands so her opinion carries some weight for me.

Thanks for a great design Bill.

For anyone considering the THT's and sitting on the fence, just go for it. You'll have fun and end up with superb speakers.
Attachments
right front in position
right front in position
Son and Neighbor doing the hard work
Son and Neighbor doing the hard work
The tractor made the move to the house easy.
The tractor made the move to the house easy.

88h88
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Joined: Mon Jul 04, 2011 10:20 am
Location: Coventry, UK

Re: 4 THT's

#36 Post by 88h88 »

Old Mike wrote:These units are just loafing in this application, barely breathing.
This is what I love about these designs. I recently moved house so disconnected the table tube I had in situ and in doing so noted the cheap little amp driving it was barely past '2' on the dial. Amazing.

Even in that room they look pretty imposing. Have you been tempted to crank them at all 'just to see' ?? :chainsaw:
4xOT12s, 2xT39s@22", TTLS@18", 2xT60@18"

Old Mike
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Joined: Thu Sep 13, 2012 12:27 pm

Re: 4 THT's

#37 Post by Old Mike »

Wife is out for hair-do tomorrow pm, she may find some things rattled off shelves when she comes back. Going to pick some movies that I know have good LFE and do a little "testing"!!!! I'm powering the THT's with four channels of my ATI amp that is good for 350 watts, more than adequate. 8)

Cranked them just a little when listening to a Celine Dion Las Vegas show Blu-ray, the last track from the movie Titanic has a very deep base plus infra-sonic rumble at the start, shook the room with zero sign of distress.

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Tom Smit
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Re: 4 THT's

#38 Post by Tom Smit »

Old Mike wrote:
The acid test, and this has been quoted so many times by so many men, my wife, unsolicited said, "I can ear the bass better, it's cleaner". She is a Jazz Saxophonist and has played in big bands so her opinion carries some weight for me.
This.
When a musician approves, ........

:ugeek:
TomS

Old Mike
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Joined: Thu Sep 13, 2012 12:27 pm

Re: 4 THT's

#39 Post by Old Mike »

Tom

That's my view also, I just wish I had the musical capability that my wife has, she really doesn't appreciate what she has, she went from zero to the highest conservatory grade on piano in just under 4 years. She then decided she wanted to play saxophone and in a similar pattern within 5 years she was extemporizing in front of a local big band. She also went back to school and obtained a music diploma, top of the class at the age of 50. All I can play is a silver disc or vinyl.

I have a friend who is also an accomplished musician, paid his way through university by playing piano, I value his opinion also, he'll be here this weekend.

I forgot to add that the home depot caulking tube sealer that I show in one of the earlier photo's worked perfectly for the whole build, I think I went through 7 or 8 of the smaller tubes of PL

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Tom Smit
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Re: 4 THT's

#40 Post by Tom Smit »

Old Mike, your wife is, indeed, gifted. To excel like that, at that rate is proof.
TomS

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DJPhatman
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Re: 4 THT's

#41 Post by DJPhatman »

Care to tell us more about the aircraft behind the John Deere? Looks like a glider, from what I can see....
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice

Old Mike
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Re: 4 THT's

#42 Post by Old Mike »

The Aircraft is an Osprey 2. A Google search will produce photographs and details. It's a 2 seat, side by side, amphibian with retractable landing gear. Normally powered with 150 HP Lycoming in overhead pusher configuration. You can see the engine mount sticking up from the cockpit, it's just there for it's weight to keep the nose wheel on the ground as a temporary measure until I mount the engine in place.

I started building it in 1986, got half way into the project after a couple of years and then a flying school arrived in the town I lived in at the time. I put the plane to one side whilst I got my license. Having my license I wanted to fly so ended up with a store bought aircraft, a Maule M5-210 which I bounced around the skies for about 10 years. Then work and travel got in the way of both flying and construction. Put in another 2 years on the aircraft towards the end of the 90's then we moved to a new city and I had nowhere to work on it, so it was hanging from the rafters of a friends hanger until we moved to our new place in the country about 6 years ago. I have now finished the house so about to start work on the plane again.

It will fly before I die. It is built from plans, as it stands now the only parts built by others are the wheels and tires, everything else you see I built. Lots of fun.

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Tom Smit
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Re: 4 THT's

#43 Post by Tom Smit »

Old Mike wrote:The Aircraft is an Osprey 2. A Google search .....
Pretty cool, Old Mike. I hope that you can get to that point soon. :clap:
TomS

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