Tad th4001/4001 + 1601 x 2

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Here's my current project-->

Picked up these big studio mains by George Augspurger. Originally they were loaded with one of his big horns, a TAD compression driver, and 2 TAD 1601's. Not sure about the tuning.

These things are pretty well built; 1 to 1.5 inch panels of high grade plywood, and ample 2X4 bracing throughout. They got beat up in the warehouse where they were discovered, so I have started the process of filling and sanding.

Since these cabs were optimized for twin 1601's, I thought a TAD 2401 type monitor was in order..but with a few inevitable twists. I have a pair of those pretty TH4001 clones Thomas (AKA Diy_HK) sells on eBay, a pair of TAD 4001 compression drivers, and two pairs of TAD (pioneer Exclusive) EL403's which are the early domestic version of the 1601. It's a lot of AlniCo!

I'll keep updating this thread as I go along- posting plenty of pictures.

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One of the challenges I faced early on was getting the TH4001horn to sit properly on the baffle, but I have it all sorted. There is a secondary baffle that overlays the area where there is currently no paint. It's a classic horn monitor trait as it serves to get the two drivers to "line-up" closer so I am told. That second baffle will be 1 inch so that it comes flush with the outer panels of the cabinet. I had to compensate for the "missing" 1 inch so that the TH4001 horn can sit flush. You are now seeing the cab without the overlay- which I will do tomorrow (weather permitting). There will be a grill to cover the 2X15 area.

The plan is to finish these in Dura-Tex or some other textured finish. Black is the color. The grill will be covered with NOS cloth for vintage JBL's. The color is "camel" as found on the beautiful L300's among others. I have been saving this roll of cloth for something special and I think this is it.

Here's a shot straight on --->

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Here are the 4001's that will be gracing these big ugly cabs:

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The 4001's get pretty ragged above 10 kHz. Even with the beryllium, it's just not possible to get smooth response that high with a 4" dome. Do yourself a favor and add a pair of the TAD 703 super tweeters. You can cross them over anywhere between 5 kHz and 10 kHz -- I'd suggest 7 kHz or so. The resulting sound will be much sweeter and less fatiguing. This is what JBL did with their recent "super" speakers for the Japanese market. I've heard them and they are outstanding. I think yours will be even better if you can afford a pair of the 703's.
 
Hi Charles,

Thanks for the advice. I appreciate what you're saying- I really do. It's something I might consider down the road...

At this point I'm focused on getting these things fired up and listening to them before I get to concerned with adding a tweeter. If they sound good to these ears, I won't let their ragged response bother me too much. If something is lacking or rough, then I will certainly do something. I might try 4002's or even 4003's before adding a tweeter because I like the simplicity of a good two way. If I do add a tweeter, the ET703 has a lot of competition...many choices, there.

Thanks!
Resident Mick.
 
At this point I'm focused on getting these things fired up and listening to them before I get to concerned with adding a tweeter. If they sound good to these ears, I won't let their ragged response bother me too much.

That's definitely a good plan! You've got some good speakers on your hands!

I might try 4002's or even 4003's before adding a tweeter because I like the simplicity of a good two way.

If you want to stick with a two-way, the best route would be to use the TAD 2001 tweeters. There is no way that any 4" dome is going to go past 8 or 10 kHz smoothly, even with the beryllium dome. The 2001 uses a 1.75" beryllium dome and it will barely reach 20 kHz without breaking up. The tradeoff there is that it won't go much below 1.5 kHz on the bottom end and again it is hard to make a two-way speaker.

If I do add a tweeter, the ET703 has a lot of competition...many choices, there.
I suppose, but those TAD's are pretty special. They have a 1" beryllium dome that will go all the way out to 40 kHz without breaking up. I don't know of many super-tweeters that can compete with the TAD's. Plus you would still have an all TAD system.

The only one that was comparable was the TAD beryllium ribbons, but those have been discontinued for several years now.

My recommendation is get them up and running. Then when you get the urge, add the 703's (or the beryllium ribbons if you can find a pair on eBay). I think you'll be pleasantly surprised by the improvement. At that point you will have speakers that compete against the $30,000 and $60,000 JBL "super" speakers.

Happy listening!
 
That's definitely a good plan! You've got some good speakers on your hands!

Thank you. :)

You should have heard all the stuff I had to say to my wife to get these...


If you want to stick with a two-way, the best route would be to use the TAD 2001 tweeters. There is no way that any 4" dome is going to go past 8 or 10 kHz smoothly, even with the beryllium dome. The 2001 uses a 1.75" beryllium dome and it will barely reach 20 kHz without breaking up.

I don't know....I've read the specs, and I've had a couple of friends go first hand down that road and they didn't exactly think the 2001 was anywhere near the 4001 at any frequency. I know I'm about to find out for myself pretty soon, though.

The tradeoff there is that it won't go much below 1.5 kHz on the bottom end and again it is hard to make a two-way speaker.

Exactly. I think the real beauty of using a large format like this is that it can sweep the whole vocal range and play with weight and authority all the way down to 500Hz without breaking a sweat. If high frequency augmentation is needed it's easy to add. Pretty hard to add good midbass/lower midrange to a 2001.



Happy listening!
Thank you. :)
 
At this point I'm focused on getting these things fired up and listening to them before I get to concerned with adding a tweeter. If they sound good to these ears, I won't let their ragged response bother me too much. If something is lacking or rough, then I will certainly do something.

There are months of listening and crossover tuning in front of you, but I believe they can sound wonderful even without additional supertweeter.
It doesn't have to mean anything, but I have Altec 288k and 902 and the large format tweeter is sweeter and better sounding than smaller one.
:up:
 
Really nice speakers! Not to belabor the point but a good tweeter will make a difference. I have been running the JBL 2435/456Be which are 3" Be drivers for a couple of years now. I was able to get my hands on a pair of the 045Be tweeters that are used in Everest and the 9800 and suitable horns . Adding them definately improved things. It really adds more than just the top octave it also helps the directivity up there, Enjoy them!

Rob:)
 
I got the upper baffle sections cut today, but before I can install them I have to add an upper and lower "cleat" for the horns to bolt to. The cleats are made from two pieces of 3/4" marine ply glued together, and then glued/screwed to the inside of the front baffle. Here's a picture of the lower cleat of one cab clamped into position. Pretty boring....:rolleyes:

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Today was also the day to drill the horns. My horns were unblemished and suited for sitting on top of a cabinet so they needed to have hardware installed to accept the mounting bolts for use in a cabinet. I used "cam nuts" like what you'd find in mass production cabinet shops. The technical name for these is something like "dowel nuts", I think. I wrapped a blanket around the horns to protect the finish and carefully clamped them to the drill press. In went a series of 9/32" holes, and the pieces fit nice and snug. Then the bolt holes were drilled from the other side and they lined up right on the money. Perfect! This part made me very nervous, and I'm glad it's over.


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I did a quick mock-up and was pleased to discover my cuts were accurate. The horns fit snug against the baffle and are airtight once I add the sealing gasket. I'm quite proud of that because making a three stage "step" baffle took a lot of head scratching and was a complete PITA. The horn has to make complete contact with each step or you will have created an air void. Again, it's another stage that's over am I'm thrilled.

I have since cut the port holes on these overlays with a template router bit- following the contour of the holes cut in the underlying baffle.

Never mind the EL403's; they need to be cleaned up a bit more. They were once mounted to the underside of a baffle and they retain some wood traces. At any rate, you can at least start to see what these bad boys will look like when fully loaded. Look out neighborhood!!


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I had to make a resting ledge for the weighty 4001 c/d's. I glued two pieces of 3/4 ply together and put it into position with more glue. After that set up I added screw cleats on the corners for extra strength. It's solid. I will be putting a small piece of felt on the part where the driver makes contact.

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Both cabs were prepped for paint by first shooting them with black primer. The primer let me see where my troubled areas were. I sanded those sections smooth and now they're both ready for finishing. I know they look ugly to you, but my heart skips a beat when I see them- even at this stage! (I have since cut the port holes, hit all the edges with a 1/2" roundover bit, drilled mounting holes for the 15's and put the 32 T-nuts in).

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That's an awesome job you're doing. Please post more pics!
Just curious how do you actually mount the horns to the cabinet.
I'm planning to get the horns from Thomas as well and building a 2402 clone cabinet. But looking at your pics now I'm really tempted to go with two 15's rather than one.
 
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