Any folks still around from the NHT surplus sale days?

[Hibernator]

Howdy y'all,

I'm a little late to the party, but am finally getting around to unpacking the big box of drivers I bought around 2007 from somebody on the East Coast selling on eBay dirt cheap.

Recently I found all the NHT sale threads and Jack Hindley's spreadsheet, so I don't know whether I got lucky and part of the sale or what, but it seems I have the following laying around:

- 10 6.5" Foster woofers from the 3.3 and 2.9
- 10 4 inch shielded drivers, appear to be from AC2 and thus the same as in the 3.3 and 2.9
- 5 tweeters I thought were Superseries tweeters, but they look like the tweeter in my AC1 and have a sticker on the back that reads "050/1 2101 NORWAY".
- 1 NHT 1259 is in the mail right now, and I have 2 new 10 inch NHT woofers (might be VT-2 replacements, but the number is not-11-125-1 so it doesn't match Jack's spreadsheet)


I would like to build myself a 3.3 clone. Since NHT 1259s are a little, umm, "hard to find" and I only have 1, I was thinking of trying to make it more of a 3.3 sat with a single 1259 sub or maybe using the other 10 inch woofers if I can find out a little more about them.


I've seen the VR-3 threads and found the plans for them as well as a (partial?) cabinet drawing for the 3.3 and a XO schematic. I was planning to use a Behringer active XO, because I am a little out of my swimlane when it comes to electronics at the moment.

Has anybody else made a 3.3 or 2.9 mid/high sat and have any advice to offer?

Is there a 2nd page to the 3.3 cabinet schematic? There are references to detail drawings and the various measurements don't all add up (overall height is 48 inches, but I added it up to be 48.883). To be fair, reading schematics isn't my day job and I could be way wrong here. Do the two mid range woofers have separate chambers or share one open volume space (this may be a dumb question to a seasoned speaker builder, sorry if it is)?

If I build the sat/sub config, is the 21 degree angle on the front no longer relevant as long as I simply point the sats at the listening position using the correct angle?

And while helping out could also be offers to take the drivers off my hands and help me clean out my garage, I will have to ever so graciously decline ...

 

[454Casull]

I bought a plate amp. Still using it.

 

[SY]

I have a few more drawings than the ones on my website- let me see if I can dig them up and make them public (I was given permission by Jack to do so). Unfortunately, I've moved three times since then...

The 3.3s are superb- you picked a fine speaker to clone.

 

[Hibernator]

Thank you very much Sy. I emailed you through your website too before I thought about posting here (just FYI).

I've wanted to hear these speakers ever since 1997 when went for the VT-2 setup with surrounds instead of the 3.3s only. Can't complain really though, the VT-2s have served us well and survived 5 cross country moves since 1997.

 

[rhubarb9999]

Hibernator, you have a PM

 

[PB2]

Hibernator, you have another PM. I got your PM, and mentioned that I simulated the 3.3 years ago in CALSOD, first taking a guess at the crossover, then updating it when it was made public. I considered cloning them but never did.

I suggested the sub-tower version many years ago so were are thinking along the same lines. You can probably find a modern woofer to use as a sub for the 1259 there is nothing real special about it or you could experiment with slightly lower crossover points and the single 1259 that you have.

I'd agree that canting in the towers should work fine as you mentioned.

I believe that the upper mid used a plastic enclosure from SEAS - not positive about that.

The lower mid was partitioned off from the 1259 space but I'd have to dig to try to determine the correct volume. It should not be very critical.

 

[Hibernator]

I'm too exhausted to try and recreate the NHT 1259 subwoofer post here tonight, so here is a link to a post with some pics:

http://thecarversite.com/yetanotherforum/default.aspx?g=posts&m=120645#post120645

WARNING --- WARNING --- WARNING

- pix are all bunched at the end, scroll down if you are not in the mood for my possibly incoherent rambling ...

- long read, don't take what I type too seriously, and remember I am doing this for fun

- I learn by understanding my mistakes, not by being told I am wrong. I say this here and will probably repeat it somewhere more visible because I have seen several threads on audio forums and even back in the old newsgroups and mail lists/digests where the new guy is seemingly berated for his plans (sometimes over the top, sometimes it's smart people really trying to help, some times the new guy is really out there, sometimes he just needs a little help here and there and doesn't care his product won't be audiophile quality). This is a can of worms and potential flame topic, so please no insult intended. Instead, I'll come back to me and why it matters:

I want to make a cool sounding speaker with a bunch of drivers I bought years ago. I am not and never will be a professional audio/design engineer. I am OK with making subpar/failed attempts and learning by it along the way. Woodworking is a hobby and keeps me sane after 8-10 hours at the computer at work. It's no big deal to me if I have to do this a few times to get to a final product.

The dream is big: "clone* the NHT 3.3" - if the choice of the word "clone" offends anybody please speak up and tell me what the more appropriate non-offensive term is. How about this: I am building a 3-way sat/sub combo and happen to have the same woofers as used in the NHT 3.3. XO and cabinet schematics are not hard to find, so I'm going to use that loosely as a starting point. "Man, it would be freaking cool if I could get even close to the incredible sound of that commercial product".

The reality is ... well, we'll see. And to me there is a lot of fun in that.

Thanks to some very generous people there is way more information publicly available than you could ever hope for, so the probability of success is way higher than you'd think, even for someone with very little audio experience. I do believe I'll end up with something pretty good.

Pretty good could mean I like/love it (but to a pro it sounds like fingernails on a chessboard), it's a pretty close to the NHT sound for a DIY speaker, or anything in between.

Or I could crash and burn along the way ... but then I have an awesome story to tell about how I had a great vision and failed worse than Charlie Brown flying a kite or kicking a football.

Geting off the soap box now... toys calling my name from the garage workshop ...

 

[Hibernator]

Where to host pics for easy linking

Testing file attachments.

-----

edit: wow, that was easy.

Pic shows dry fit of woofer and front baffle. Glueing interior braces and front tonight.

 

[SY]

I found a few more of the drawings for the NHT box. I'll have them up later today.

 

[PB2]

Here are links to SY's page on the 3.3 and thread:
http://syclotron.com/?p=160

http://www.diyaudio.com/forums/multi-way/124455-nht-3-3-modifications.html

 

[PB2]

I think what I would do is to build the small towers as you have planned to match the original 3.3s. Take one of the towers positioned where it would be as a true 3.3, and place the one sub box behind it turned so that the woofer is in the correct location. Then build a copy of the original crossover - use this as your reference. We could probably find a modern drop in replacement for the 1259 and if you are willing to build a second box you could test it with the second tower, or measure the 1259 based system, then swap the drivers. It would be nice to have a known and tested drop in replacement for the 1259 - well really for all the drivers.
Do you have any interest in a second sub?
Then you could test an active version of the woofer to tower crossover, similar to what SY did, where you'd have the reference to be sure that they actually measure and sound the same.


This is probably the closest for the upper mid - I've not checked the specs:
The Madisound Speaker Store

I'd probably go with this for the tweeter even with the fabric dome since it will probably otherwise drop in with minimal changes - again I'd check the specs before final selection:
The Madisound Speaker Store

Edit: you could even put up a temporary baffle extension around the 1259 to give it the same size as the original 3.3 to make your reference closer to the original. Then you could see if there is a significant difference and look for ways to compensate in the active or even passive crossover.

 

[Hibernator]

Thanks y'all. Jack was kind enough to send me some files too, so I've got my hands full now ...

Will check Sy's site too.

Questions:

1. As for XO components (or more general, I have a few older amps that need to be refreshed), where do you prefer buying these?

I've seen Mouser and Digi-something mentioned in other threads, but haven't ever gone beyond Radio Shack before in this area. I get the feeling mail order is it, right?

Are there perhaps any brick and mortar places around LA (northern LA: Santa Clarita, Burbank or Ontario are closest)? How about Fry's, or is their selection too computer related?

2. For fun I'm going to try and cut and assemble two rough enclosures today. I'm going to try to made one square and thus modify the depth to compensate. The other will be with the angled front, but with 3/4 MDF.

- if I keep the front baffle 7.5" the interior will be 1/2" wider, so I will shorten the depth.

Am I being too worried about small changes in enclosure volume?

------

SW wise I'm currently limited to the WinISD stuff, bassbox, and the latest DATS from Parts express. Prefer using Mac, but have PC available necessary. I used REW once to help measure an open baffle 3-way experiment using FIR software XO and one of the Tripath multichannel amps all on my Mac. This was some kind of voodoo combination of Soundflower (for the love of God could not figure out JackOSX), beta version of Plogue Bidule, and Matlab. Wish I had made some paper notes, that was about 2 years ago and I can't quite figure it out now. The goal was to learn if it could be done (more specifically if I could do it): use software XO and achieve pretty flat freq response in a multiway speaker. Worked out pretty well for a breadboard level approach.

Sorry, rambling again, but I think I'm heading towards this:

- it's a no-brainier to give the XO a shot given the schematics are available. That's the gold standard and it also allows normal/easy hookup to any normal amp.

- the Behringer DCX2496 will also be given a shot, maybe in the end this will be my sub/sat divider only.

- a digital XO (possibly with room correction) will be tested. Love this idea as a computer nut, especially as this was what really got me to take the plunge and try to build more than just a subwoofer. Downside is this isn't going to be something my wife will be turn on and using very easily ... or is that an upside, cough, umm, ...

 

[Hibernator]

Interesting ideas. Need to do a few things first, but this has some neat implications beyond just an awesome DIY speaker for my listening room.

I think what I would do is to build the small towers as you have planned to match the original 3.3s. Take one of the towers positioned where it would be as a true 3.3, and place the one sub box behind it turned so that the woofer is in the correct location. Then build a copy of the original crossover - use this as your reference. We could probably find a modern drop in replacement for the 1259 and if you are willing to build a second box you could test it with the second tower, or measure the 1259 based system, then swap the drivers. It would be nice to have a known and tested drop in replacement for the 1259 - well really for all the drivers.
Do you have any interest in a second sub?
Then you could test an active version of the woofer to tower crossover, similar to what SY did, where you'd have the reference to be sure that they actually measure and sound the same.


This is probably the closest for the upper mid - I've not checked the specs:
The Madisound Speaker Store

I'd probably go with this for the tweeter even with the fabric dome since it will probably otherwise drop in with minimal changes - again I'd check the specs before final selection:
The Madisound Speaker Store

Edit: you could even put up a temporary baffle extension around the 1259 to give it the same size as the original 3.3 to make your reference closer to the original. Then you could see if there is a significant difference and look for ways to compensate in the active or even passive crossover.

 

[PB2]

I would not worry about small differences in internal volume, just make it the same externally. You can always add some fill, but you really won't have to.

Madisound, Parts Express, and Meniscus are my main sources for parts. Most ship fast, I would not worry about it. Oh, and Zalytron. Apex Jr. if you are interested in surplus parts.

 

[PB2]

Here are the 1259 specs that looks like the old Madisound ad:
NHT 1259

I believe that there was an early and late version of the 1259, that
looks like the early version.

Here are partial later specs I believe, Fs up to 19 Hz and a lower Vas,
the Qs also change but this will happen just due to the Fs change. Some
measured results also:
http://www.diysubwoofers.org/projects/home/1259/homepage.htm

The Infinity 1260W comes to mind as a potential replacement - simulations
would be required to confirm:
http://us.infinitysystems.com/tl_fi.../Reference/Reference/1260w/REF1260W_PI_EN.pdf
Same Xmax, and Rvc. Suspension is stiffer, but cone mass is higher,
might just end up compensating. Higher mass lowers efficiency, but it
has a stronger motor - higher Bl. They rate it at 93 dB/2.83 V, but
sealed response curve shows about 90 dB/2.83V in the passband. A
fairly inexpensive driver.

 

[PB2]

Here is a .pdf of the MAD1259 that they say is different enough that they've renamed it:
http://www.madisound.com/pdf/MAD1259.pdf

They say it is not a direct replacement.
This might not actually be true, it looks as if the Vas, Fs, and Qts are a very close match
for what was measured here on actual 1259s:
http://www.diysubwoofers.org/projects/home/1259/homepage.htm

 

[PB2]

Too late to edit my post.
Here are the official later specs, 19Hz Fs 190l Vas, note the incorrect info
for maxSPL vented, lol, that was in response to my suggestion on the Bass
List for vented alignments!
http://www.kenkantor.com/press_clippings/NHT1259_FAQ.pdf

Here are the 1259 specs that looks like the old Madisound ad:
NHT 1259

I believe that there was an early and late version of the 1259, that
looks like the early version.

Here are partial later specs I believe, Fs up to 19 Hz and a lower Vas,
the Qs also change but this will happen just due to the Fs change. Some
measured results also:
Bill Eckle's NHT 1259 projects

The Infinity 1260W comes to mind as a potential replacement - simulations
would be required to confirm:
http://us.infinitysystems.com/tl_fi.../Reference/Reference/1260w/REF1260W_PI_EN.pdf
Same Xmax, and Rvc. Suspension is stiffer, but cone mass is higher,
might just end up compensating. Higher mass lowers efficiency, but it
has a stronger motor - higher Bl. They rate it at 93 dB/2.83 V, but
sealed response curve shows about 90 dB/2.83V in the passband. A
fairly inexpensive driver.

 

[Hibernator]

It's not pretty ... it's functional!

Got the sub inside and hooked up. I just got three new Carver PM1.5t amps and am using a sub out from my Denon AVR-3600 with a converter cable into one of the XLR inputs on the amp.

Oddly I couldn't get any sound from the first amp. There's a label on the back about 1.5 mV sensitivity, so maybe that's not what I'm used to with non-pro gear. Will have to see about that.

The pics show the internal bracing, my 1st ever attempt at soldering, and the very temporary setup in our formal dining/living room open area.

The Denon crosses are 80 Hz and I am using the VT-2s as "small" speakers driven by a Carver M4.0t.

Overall I like it. Maybe I'll try to figure out DATS or something tomorrow and see if I can measure test tones and response (REW maybe?).

Off to hopefully make some sawdust and sat enclosures.

 

[Hibernator]

Dry Fit Mockup

After stewing over this for what seemed like way to long, drawing up schematics over and over again (adjusting for 3/4 MDF or whatever), I kind of just took the original NHT schematic and started making sawdust tonight. I had decided from the beginning to start with the face plate and make it full length. Looking at the pictures now though I am going to have to double check the measurements tomorrow when I make the fixes and hopefully glue it up.

For example mitering the fronts of the sides. I just could not figure out what went wrong when the front baffle (nicely mitered at 21 degrees) didn't want to rest comfortably on top of the lower section sides. Once I cut the top I figured it out though. I might have cut the top side panel a little too narrow on the shorter side of the speaker. Other than that I am pretty sure everything either already fits or was cut slightly large and just needs to be trimmed properly.

I think the design looks excellent, much better than trying to adjust the middle horizontal higher in order make both enclosures have the same depth (although that would be a lot easier to construct). Looking way too far ahead, it might be worth having a cool looking design like this and a square box design where the user twists the speakers 21 degrees towards center on his own. That would open up construction to a lot more people.

 

[tomtt]

Are there perhaps any brick and mortar places around LA

(northern LA: Santa Clarita, Burbank or Ontario ...

might try here - several blocks west of van nuys on oxnard .

14928 Oxnard St. Van Nuys, CA 91411

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