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NHT speaker help needed

In the end, it is all about the music. Thanks for letting me contribute to that end. And yes, I'm a bit over the top with trying to have things survive shipping! :) I have embraced my inner geek! Reading your posts, Dan and Ken, has me smiling! Gotta love this place!
 
ronrico said:
Looks great,but sounds much better. I got the woofs installed in the cabs and at first blush sound very good in the man cave. The real test will be in the living room, but first...... NHT speaker help Part Deux.
Click to expand...


Nice thread here.

I really like the NHT products I have heard The pro A-10 amplifier/speaker combo is my favorite. Along with the 1.3a, 1.5 etc. In addition to the pro A-10 set up, I have a couple of 1.1c speakers that need to restored. The"c" is a magnetically shielded version of the 1.1 it lacks the slanted baffle. I'm curious to know what the final tweaks on you 1a will be.

Look the packing job on those woofers. :) like artwork as Ken pointed out.
 
michiganpat said:
Ken- what's the design of this speaker, as far as crossover point? does the woofer run full range? I wonder if these drivers would work well in them:

http://www.humanspeakers.com/cgi-bin/page.pl?page=diy/parts/007.txt

6.5" woof with a 32hz Fs and 29L Vas....would be nice if Huw had FR charts, but he lists 40-2khz +/-2db for response.....
Click to expand...

10 uF cap on the tweeter for first-order HP filtering with a corner frequency of about 2KHz, IIRC. Nothing on the woofer, so it runs full range.

That woofer has roughly the specs I'd be looking for in building a two-way sealed speaker with a 6" woofer. In a critically-damped box (Q = .707 at about 44.5 liters) it will have a bass corner frequency of about 41 Hz. That seems pretty good for a 6" woofer.

That may seem like a big box for a 6" driver, however. You can cut the box size in half and the Q only rises to .835, and you may even prefer the sound. Corner frequency only rises to a bit over 42 Hz.

Looks like he builds it in a box with an internal volume of only 13 liters, which moves the Q up to around 1.0 and the corner frequency to 45 Hz. Looks like the NHT 1A is a bit smaller so the Q will go even higher. Might not be the best fit, if the box size is fixed by an existing speaker.

Cheers,

Otto
 
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ronrico said:
Looks great,but sounds much better. I got the woofs installed in the cabs and at first blush sound very good in the man cave. The real test will be in the living room, but first...... NHT speaker help Part Deux.
Click to expand...

Once you have the AR woofers mounted in the NHT boxes, you might want to try putting a
1mH inductor in series with the woofer.

I'll explain the differences and similarities of the woofers later, as well as reviewing the unusual approach used in the NHT 1x crossovers.

I'm looking forward to seeing how this works out for you!

-k
 
Bostown said:
Nice thread here.

I really like the NHT products I have heard The pro A-10 amplifier/speaker combo is my favorite. Along with the 1.3a, 1.5 etc. In addition to the pro A-10 set up, I have a couple of 1.1c speakers that need to restored. The"c" is a magnetically shielded version of the 1.1 it lacks the slanted baffle. I'm curious to know what the final tweaks on you 1a will be.

Look the packing job on those woofers. :) like artwork as Ken pointed out.
Click to expand...

Thank you, Sir! You definitely bought me a lunch, or three, over the years!

-k
 
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michiganpat said:
Ken- what's the design of this speaker, as far as crossover point? does the woofer run full range? I wonder if these drivers would work well in them:

http://www.humanspeakers.com/cgi-bin/page.pl?page=diy/parts/007.txt

6.5" woof with a 32hz Fs and 29L Vas....would be nice if Huw had FR charts, but he lists 40-2khz +/-2db for response.....
Click to expand...

I promise to discuss this soon, as time permits.

Meanwhile, no, I wouldn't recommend this driver for the NHT Model 1x speakers. Besides the fatal lack of curve information, there are many differences from the NHT driver design. No doubt the Human is a fine unit, just very different.

-k
 
ken kantor said:
I promise to discuss this soon, as time permits.

Meanwhile, no, I wouldn't recommend this driver for the NHT Model 1x speakers. Besides the fatal lack of curve information, there are many differences from the NHT driver design. No doubt the Human is a fine unit, just very different.

-k
Click to expand...

I'll be interested to hear your thoughts, Ken. In the mean time, it's another example of how a quality speaker design is an integrated whole. Trying to swap in a different driver that "fits the baffle opening" will rarely if ever be a close fit in terms of giving the same overall performance. Of course, sometimes the new sound might be preferred, at least by some, but it will generally be different.

I'll also add that I just got my first pair of NHT speakers in the mail yesterday, a pair of SuperZeroes, and really like them. If I were looking for a slightly larger set of speakers with more extended low end, I'd probably just snag a pair of SuperOnes or another one of the NHT bookshelf models with the 6.5" woofer, rather than taking the trouble to design one from scratch. Those slightly used models are really a bargain at the prices they go for now.

Cheers,

Otto
 
Ken,
Thanks for taking an interest in this discussion. The NHT 1As sound great, Part Deux that I was referring to was the problem that I was experiencing with the SW1 that I got with the 1As. The sub distorts badly when the volume is turned up past about 9:00. It is rated at 20 to 150 watts, but the drivers start to buzz like crazy at only moderate volume, at lower volume there is no distortion. Most of this acoustic engineering stuff is over my head, but it seems as if the woofers should be dampened somewhat as they seem to really flail ( that's real stereo-speak there) when the volume is turned up to reasonable levels. This problem is with the sub woofer not the 1As, which sound quite good.
 
Passive 6.5" right? Might need a recone if it was pushed before you got it. If so, I'd guess about $40-$50 for the repair. Looking at the spreadsheet... No Specs. One on the bay, but over in 4 minutes (woofer). (looks like the auction relisted ... Plenty of time now)
 
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Hi Herb,
Yes two 6.5" Peerless woofs with two 250uf caps and two iron-core inductors. I'm driving it with a Pioneer SA-6500II, volume knob at about 9 o'clock.
 
:headscrat Well, I certainly missed those specs! The problem is a bit baffling.
Sorry to have sent you on a wild goose chase.
 
The surrounds are rubber. I've seen rubber surrounds that got stiff with age, could it be that these have gotten soft and are allowing too much movement?
 
The were likely overdriven at some point which might have damaged the voice coils. Did you notice a part number on the woofers?
I'm not familiar with that amp, are you sure it is working properly and has enough power?
 
Hi Pete,
Thanks for jumping in. I have read many of your posts, especially those relating to the Advent NLAs. Great info there.
The part # is 831690. Visually they appear to be fine, no rub, surrounds in good shape, spider in tact and attached and cab and woofer to cab seal is good. They just really seem to be 'overly exuberant'.with even moderate power thrown at them. They are rated at 150 watts, so they should be able to take some fair amount of power.
 
Ken,
You mention putting a 1mH inductor in series with woofer in the 1As. What will this do? Would using the SW1 change the need for doing that?
 
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