NX-Otica...MTM...or Wedgie?

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Jaytor

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Re: NX-Otica...MTM...or Wedgie?
« Reply #20 on: 17 Dec 2019, 12:11 am »
Thanks guys. I can't wait to get the room treatments installed. Dec 30 ship date according to GIK. I'm also going to do some curtains on the windows to soften up the look a bit and absorb a little bit of the high frequency reflections. These will probably have minimal affect on the acoustics though.

The subwoofers have only been done for a few days, so I'm sure there is some more break-in required. I haven't spent a lot of time trying to dial them in yet since I figured that break-in and room treatments would likely affect the settings at least a bit.

RonP

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Re: NX-Otica...MTM...or Wedgie?
« Reply #21 on: 17 Dec 2019, 01:45 am »
That's a killer looking setup, Jaytor!

About to order some GIK panels myself.

Keep us posted on the sound please.

gguy

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Re: NX-Otica...MTM...or Wedgie?
« Reply #22 on: 18 Dec 2019, 03:14 am »
Just placed my order for the NX-Oticas and 3-sub H-Frames.

Are you guys crossing over the Oticas to the subs, or are you running them full range?  I’m wondering if I still need my Marchand crossover.

Danny Richie

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Re: NX-Otica...MTM...or Wedgie?
« Reply #23 on: 18 Dec 2019, 03:38 am »
Just placed my order for the NX-Oticas and 3-sub H-Frames.

Are you guys crossing over the Oticas to the subs, or are you running them full range?  I’m wondering if I still need my Marchand crossover.

I would keep stuff like that out of the signal path and just use a single inline cap to roll off the bottom end.

Jaytor

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Re: NX-Otica...MTM...or Wedgie?
« Reply #24 on: 18 Dec 2019, 04:02 am »
I am using an inline cap (actually two per channel since I'm running balanced). I spliced these into the cable and hid everything in a small bakelite box that snaps around the cable.

I ran the NX-Oticas full range for the first couple of weeks and I do think they sound a bit better with the inline caps - particularly bass notes like double-bass and tympani drums.

gguy

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Re: NX-Otica...MTM...or Wedgie?
« Reply #25 on: 18 Dec 2019, 04:15 am »
I am using an inline cap (actually two per channel since I'm running balanced). I spliced these into the cable and hid everything in a small bakelite box that snaps around the cable.

I ran the NX-Oticas full range for the first couple of weeks and I do think they sound a bit better with the inline caps - particularly bass notes like double-bass and tympani drums.
I would keep stuff like that out of the signal path and just use a single inline cap to roll off the bottom end.

Thanks.  Jaytor, how did you establish what’ value capacitor to use and what frequency to target?


Jaytor

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Re: NX-Otica...MTM...or Wedgie?
« Reply #26 on: 18 Dec 2019, 05:24 am »
Quote
Jaytor, how did you establish what’ value capacitor to use and what frequency to target?

First, you need to find out the input impedance of your power amp. My JC5 has 33K ohm per leg for the balanced inputs. Then find a capacitor value that will have a -3db point around 70Hz or so. The specific frequency isn't that important, but I think somewhere between 65Hz and 80Hz is probably a good range for these speakers. Danny can correct me if I'm wrong.

The f-3db point is calculated as 1/(6.28*R*C). Here's a link to an online calculator.

http://www.learningaboutelectronics.com/Articles/High-pass-filter-calculator.php

I went with 0.068uF caps which results in a -3db point of 71Hz. I used Gen II Sonicaps that I got from Sonic Craft.

There are probably better caps (such as Miflex copper caps) if you can find them in a size that will work for you. The Sonicaps were the only high quality caps I could find that were easily found in a value that would give me a cutoff frequency in the range I was looking for.

If you have a Parasound amp, they list the input impedance of all their amps on their website.


gguy

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Re: NX-Otica...MTM...or Wedgie?
« Reply #27 on: 18 Dec 2019, 08:01 pm »
First, you need to find out the input impedance of your power amp. My JC5 has 33K ohm per leg for the balanced inputs. Then find a capacitor value that will have a -3db point around 70Hz or so. The specific frequency isn't that important, but I think somewhere between 65Hz and 80Hz is probably a good range for these speakers. Danny can correct me if I'm wrong.

The f-3db point is calculated as 1/(6.28*R*C). Here's a link to an online calculator.

http://www.learningaboutelectronics.com/Articles/High-pass-filter-calculator.php

I went with 0.068uF caps which results in a -3db point of 71Hz. I used Gen II Sonicaps that I got from Sonic Craft.

There are probably better caps (such as Miflex copper caps) if you can find them in a size that will work for you. The Sonicaps were the only high quality caps I could find that were easily found in a value that would give me a cutoff frequency in the range I was looking for.

If you have a Parasound amp, they list the input impedance of all their amps on their website.

Got it.  I have an A21, I believe the input impedance is the same.  Are you running the subs off of the loop outs from the back of the JC-5

Jaytor

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Re: NX-Otica...MTM...or Wedgie?
« Reply #28 on: 18 Dec 2019, 08:35 pm »
I'm using the RCA outputs from the preamp for the subs and the balanced (XLR) outputs for the JC5. Yes, the input impedance of the A21 is the same as the JC5.  So 0.068uF or a little smaller (which will raise the cutoff frequency) should work fine.

You don't want to use the loop outs from the power amp since the amp won't be getting the lowest frequencies after you add the inline filter caps.

gguy

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Re: NX-Otica...MTM...or Wedgie?
« Reply #29 on: 6 Jan 2020, 09:48 pm »
Everything should be arriving here in the next week or two.  I do have a few questions.

-  Due to time and space restriction to do a good quality paint job, I am planning to use Duratex for both the speaker and sub cabs.  Has anyone used the white Duratex and can comment on any issues?

-  Should I paint on the Duratex prior to gluing up everything?


mlundy57

Re: NX-Otica...MTM...or Wedgie?
« Reply #30 on: 6 Jan 2020, 09:57 pm »
I haven’t used the white DuraTex so can’t comment on that but glue everything up and do all filling, sanding, edge profiling (if any) before applying the Duratex. The DuraTex is the last thing you do.

Jaytor

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Re: NX-Otica...MTM...or Wedgie?
« Reply #31 on: 6 Jan 2020, 10:46 pm »
@gguy - One issue I ran into was mounting the tweeter in the waveguide. This is a very tight fit. I made the mistake of painting the routed out area where the tweeter fits into the back of the baffle and the thickness of the paint prevented the tweeter from seating correctly. I had to use a dremel with a router bit to clean out all the paint so that it would fit in correctly. So...I'd recommend masking this area off before painting (back side only) so that the tweeter fits snugly against the back of the waveguide.

- Jay

gguy

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Re: NX-Otica...MTM...or Wedgie?
« Reply #32 on: 6 Jan 2020, 10:49 pm »
@gguy - One issue I ran into was mounting the tweeter in the waveguide. This is a very tight fit. I made the mistake of painting the routed out area where the tweeter fits into the back of the baffle and the thickness of the paint prevented the tweeter from seating correctly. I had to use a dremel with a router bit to clean out all the paint so that it would fit in correctly. So...I'd recommend masking this area off before painting (back side only) so that the tweeter fits snugly against the back of the waveguide.

- Jay

Thanks for the heads up.  What kind of paint did you end up using?

Jaytor

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Re: NX-Otica...MTM...or Wedgie?
« Reply #33 on: 6 Jan 2020, 11:30 pm »
I used Zinsser BIN Shellac primer (light sanding after each or two coats) and Benjamin Moore Advance Satin. The BM Advance is a latex paint but flows like an oil paint. I used a roller and brush. Not quite as smooth as spraying, but this paint works quite well at hiding brush strokes.