Cool X-over

John Casler · « **on:** 30 Jan 2004, 12:09 am »

Some time ago I mentioned a special "add on" circuit, I had set up with Marchand Electronics to allow you to have the x-over connected to both your 2 channel preamp outputs and the LFE output of your HT reciever or processor.

This would allow you to have a specific crossover setting via the 2 channel system for music, and then "bypass" that and allow the HT Pre/pro to handle the "bass management" for HT duties.

Well this made the crossover over $899 list

Recently I found the NHT X-2 crossover, which I have been told does the same thing at a retail price of $350. (it also has balanced connections!)

I have ordered this device for my demo system and will review it after it arrives, but for those with "passive" subs, this looks like it could be one sweet little unit.

While not much info is available, much of the specs are the same as the X-1 (which has specific equalization to the NHT speaker systems)

http://www.nhthifi.com/2004/products/product_detail.asp?ProductLineID=2&ProductID=47

Should have it in about 2 weeks. I'll let you know how it sounds

rkapadia@ROOP · « **Reply #1 on:** 30 Jan 2004, 01:40 am »

John,

I fooled with this crossover a bit; while I think it's an excellent price performance solution I just couldn't convince myself the X2 was completely transparent for serious two channel listening. Still, that might just be that I'm spoiled by the VMPS ribbons on the RMX

.

Please post your impressions or if you find a tweak that improves the performance of the NHT crossover, because it really would be a fantastic solution at a great price.

Regards,

Lupo · « **Reply #2 on:** 6 Feb 2004, 01:15 am »

John, I am looking forward to your comments on the X2. I am assuming you'll test it with a VMPS larger? If so, how do you feel about the following feature of the X2, in regards to the VMPS larger?

" response is down 3dB at 20Hz and then rolls off at 12dB/octave "

John Casler · « **Reply #3 on:** 6 Feb 2004, 02:17 am »

Quote from: Lupo

John, I am looking forward to your comments on the X2. I am assuming you'll test it with a VMPS larger? If so, how do you feel about the following feature of the X2, in regards to the VMPS larger?

" response is down 3dB at 20Hz and then rolls off at 12dB/octave "

Hi Lupo,

I haven't seen that number but I think the LF lower limit can be adjusted according to Jack Hidley NHT Director of Engineering.

According to him:

Quote

We can make the X2 go as low in frequency as we want to. We choose to make it roll off at 20Hz so that it can be used with ported subwoofers. With a ported subwoofer, it is critical to filter out frequencies below the port tuning frequency. If you don't do this, you will get a lot of distortion. It is a simple job to modify the circuitry in the X2 to make the low frequency cutoff whatever you want it to be.

And you are correct, I will be using the X2 with a Larger or two.

Where did you find that info?

Lupo · « **Reply #4 on:** 6 Feb 2004, 03:02 am »

I am quoting Jack Hidley from the X2 forum over at the NHT web site:

http://www.nhthifi.com/forum/topic.asp?TOPIC_ID=47

Quote

The X2 is shipping now. It has been for a month or so.

The X2 is exactly the same product as the X1 with a few changes.

There is no low frequency eq on the subwoofer output. The response is down 3dB at 20Hz and then rolls off at 12dB/octave.

The low pass filter is adjustable over a much wider range than the X1 is. On the X2, the low pass filter can be adjusted all the way up to 220Hz.

The X2 can be purchased directly from NHT.

The X2 is designed to allow biamping of virtually any sub/satellite or 3 way tower loudspeaker. See the Evolution section of this website for full details on the X1.

Jack Hidley
NHT Director of Engineering

John Casler · « **Reply #5 on:** 6 Feb 2004, 04:19 am »

Looks like we're "on the same page"!!!

I'll let you know how it sounds.

ekovalsky · « **Reply #6 on:** 6 Feb 2004, 06:36 am »

I played with several active crossovers when I had my Apogee Divas. Most did more damage than good, specifically killing transparency in the midrange and treble. Probably this is why Brian encourages passive biamping, or using an active filter only on the bass section and running the mid/treble full range with the passive crossover.

The only crossover I found sonically invisible with the Apogees was the "personality card" incorporated into a Muse18 subwoofer. It's high pass filter, set at 70hz, fed what I perceived to be an uncorrupted signal to the main amplifier.

Before the Muse I had a Velodyne ULD18-II which had wicked good bass but I had to run it in parallel with the Apogees, its high pass filter was horrible! Running the sub with the speakers full range made integration basically impossible, plus I lost the advantage of removing the very low bass from the big Apogee woofer panels.

I have never heard the Marchand units although they seem to be well made. Pass Labs makes a very nice and flexible unit but it is very expensive. The Bryston has been around forever and is pretty good too. For severals years I've wanted to try a digital crossover (TacT or Accuphase) but haven't had the opportunity yet.

Lupo · « **Reply #7 on:** 6 Feb 2004, 02:18 pm »

Quote

I played with several active crossovers when I had my Apogee Divas. Most did more damage than good, specifically killing transparency in the midrange and treble

No argument there but the fact remains that the VMPS larger needs a crossover and word is that Brian's crossover leaves a lot to be desired. Your post reiterated the proverbial conundrum: convenience vs. sound quality for those wishing to combine 2ch/mch + HT .

With the proliferation of SACD and the lack of any meaningful digital out solution, I wish someone would just come up with a quality analog 5.1 preamp + crossover + remote. Sony was close with the Stereophile Class A TA-P9000ES (no built-in crossover) but they discontinued it-another proof that big companies basically don't give a rat's ass about the sound-just the $.

Even removing any HT and mch factors, you’d have to Y-out the Front L & R signals, run an active XO on the subwoofer side and then feed the sub amp, or install a passive XO right before the larger (perhaps a Marchand XM46-A). Then again there are those who curse Y-cables. So what’s the answer?

John Casler · « **Reply #8 on:** 6 Feb 2004, 02:51 pm »

Actually the best X-over I ever used or heard was the DP-LQ1 from Dahlquist, which I still have.

Harry Pearson called it the 8th Wonder of the World (I know, I know

)

Actually I still have it and would use it, except that it is so old that the RCA jacks can't take the pressure of the newer tighter cables and replacing them is quite a task.

But it is quite a performer, and if used in the area of 40hz down, it works quite well.

ekovalsky · « **Reply #9 on:** 6 Feb 2004, 03:32 pm »

I guess if Alon uses it in their $120,000 "Exotica Grand Reference" it must be pretty good

John, you should get that bad boy modded and put it to work. Think how good it would be with some Cardas or WBT posts and state of the art passive parts inside.

See last paragraph at http://www.alonbyacarian.com/products/exoticagr_b.htm

James Romeyn · « **Reply #10 on:** 6 Feb 2004, 07:18 pm »

John Curl's Vendetta & the older VMPS LP-only XOs are the two best I've heard. The core of the VMPS XO is from an automotive application (Alphasonik); a mutual friend referred the piece to Brian. My friend recently said that the quality of the newer Alphasonik cores had decreased, & the older pieces sound better. I think that a parametric EQ is a huge addition to any good LP XO.

John Casler · « **Reply #11 on:** 6 Feb 2004, 08:45 pm »

Quote from: ekovalsky

I guess if Alon uses it in their $120,000 "Exotica Grand Reference" it must be pretty good

John, you should get that bad boy modded and put it to work. Think how good it would be with some Cardas or WBT posts and state of the art passive parts inside.

See last paragraph at http://www.alonbyacarian.com/products/exoticagr_b.htm

Eric,

Very cool, After seeing that I just may get it repaired. That is the exact model I have, but it does need a new PC and a whole array of input jacks (one is just dangling)

I have examined the inside and I doubt it would support todays stronger jacks, Might have to "jury rig" something.

Thanks for the update. I had no idea it was "that" good, but "back in the day" it was well regarded.

bubba966 · « **Reply #12 on:** 6 Feb 2004, 08:55 pm »

If you're going to replace the jacks, you should look into these

http://www.audiocircle.com/index.php?topic=6507

ekovalsky · « **Reply #13 on:** 6 Feb 2004, 08:59 pm »

You should contact Ric at EVS or Steve at Empirical Audio, or maybe Chris Johnson at Parts Connexion. I bet they could dissect it and rebuild it with better parts with a new chassis and connectors.

I'd be interested in one myself to use with a pair of VMPS largers, for home theater applications only of course

One day I'd really love to hear that Alon system, it looks amazing!!!

John Casler · « **Reply #14 on:** 6 Feb 2004, 09:29 pm »

Quote

One day I'd really love to hear that Alon system, it looks amazing!!!

Yeah, I'm up for that. I might even be good enough to give the RM/x's a good run, but at $120,000 it should.

John Casler · « **Reply #15 on:** 6 Feb 2004, 09:34 pm »

UPS has delivered the X2 and out of the box it looks pretty substantial.

Poop sheet says: 105db S/N at Hi Pass out and 100db at sub out

Thats not bad.

Also says 15-220hz +/- 3db LFE input

Film at 11:00

Lupo · « **Reply #16 on:** 6 Feb 2004, 11:10 pm »

John, from what I've seen on another thread. there are a good number of people here trying to combine 2ch/HT the "right way"-whatever that is

Needless to say, your info on the X2 is eagerly awaited.

On another note, I wanted to briefly comment on the VMPS larger by tiping my hat to Brian Cheney for creating this thing. This subwoofer is nothing short of spectacular. It's astonishing how such a big sub can be so good with music AND HT.

JonPugmire · « **Reply #17 on:** 14 Feb 2004, 02:41 am »

I'm still contemplating one of these, any impressions so far?

James Romeyn · « **Reply #18 on:** 14 Feb 2004, 04:05 am »

Quote from: Lupo

...the VMPS larger (sub) by tiping my hat to Brian Cheney for creating this thing. This subwoofer is nothing short of spectacular. It's astonishing how such a big sub can be so good with music AND HT.

Lupo
Years ago (decades?), when it was "2 guys in a garage", an LSW would burn in playing music, with no other speaker. It was truly enjoyable & incredibly musical hearing the bass notes play with so much realism & authority, even the older tower version with thinner cabinet walls, no SoundCoat, & inferior drivers. I also like "spectacular" to describe the LSW, but my wife the children's book author says "spectacular" can be properly used only as a visual descriptor. I'm too lazy to confirm but maybe one of the readers could check a dictionary for us...If she is correct, the LSW looks awright, but maybe not "spectacular".

John Casler · « **Reply #19 on:** 14 Feb 2004, 03:08 pm »

Quote from: JonPugmire

I'm still contemplating one of these, any impressions so far?

Hi Jon,

So far this is a great little unit. Just before it arrived, I separated my HT and audio system so I haven't been able to test that function yet, but will try to soon.

I currently have it in use as a sloped filter to my LARGER VMPS sub, while running the 626Rs full range. I didn't want to interfere with the great bass I was getting with the 626's, so I slope the sub in from 50Hz down.

The X-2 has continuosly adjustable frequency, with a 12db slope.

The blend is seemless and the results are "far" better than I expected.

It also has "phase" adjustment and "boundary equalization".

I'm very happy with it so far and I'm thinking I could test the LFE input with the 5.1 analog out of the DVD player.

The true test on this is FLight of the Cosmic Hippo by Bela Fleck and the Flecktones. The bass is not only DEEEEEEEEP, but it is transparent and "all encompassing". That is it plumbs the very low 20s (or even teens) but has this organic (read wholistic) integration that makes the room dissapear even more.

I am a big "depth" nut, and this bass, in this system, removes the walls and shakes the couch at the same time. And all this from a pair of 626Rs and a "single" LARGER sub.

I should mention that I also use the 3 channel CineNova 600wpc x 3 to power it all.

Couple this with the MiniMax, and it is a very engaging system.

I can only imagine what it would be like with a pair of RM30s and "stereo" 215's

You'd have to take your nitroglycerin as a precautionary measure during listening prep