In-wall NSB line array!

[morbo]

If it was me, I would leave this project behind, if your brother is happy call it mission accomplished, and move onto a project that you can make worth the time you sink into it (ie one that is not held back by a $15 budget).

[johninCR]

Originally posted by morbo
If it was me, I would leave this project behind, if your brother is happy call it mission accomplished, and move onto a project that you can make worth the time you sink into it (ie one that is not held back by a $15 budget).

I disagree totally. Mazeroth has to listen to them too and half-a**ed projects or ones never finished gives DIY a bad name. Take pride in your work and make the most of what you have even if it's just putting some varnish on the cones to tame the top end some on the NSB's and using only the Onkyo cap.

[mazeroth]

Yeah, I will be down there quite a bit and when our friends come over to jam and hang out I'd like for them to enjoy the speakers as well. As far as adding more drivers, that might be tough. We had to have the HDF cut into 3 sections so it could fit into the back seat of his Cavalier! The way it's set up now I am running as many as I can vertically on one piece. I'd have to take another piece down and drill that one out. If I do that, the center to center spacing will suffer at the seam so I don't think it will be worth it.

How well do you guys think using something like Winamp to help the 7khz hump will do? Or are there better, free EQs for the computer? We'll be using an older laptop as the source.

Thanks!

[cjd]

The 7k bump is *very* narrow - not something WinAmp can tame without killing other frequencies.

Which Onkyo tweet are you using? Must not be the 269-702 with your comments regarding the sensitivities.

Regardless, you can get what you need without much investment. 3rd or 4th order acoustic slopes don't always require lots of components in the crossover.

I (think I) surprised a few folks with my "all spare parts, so not really optimized, and never measured" $9 open baffles using NSBs and an Audax tweet (mini tweet like the Onkyos that was a buyout way back) at the recent DIY event here in Chicago. Not sure if the surprise was "he had the guts to bring something that bad" or "huh... better than I would have expected".

C

[johninCR]

Maz,
A small gap on the NSB's will have almost no effect. I have a 4" gap where my tweeter is. A gap in the tweets might have an effect that you could hear but only when your ears are slowly moving thru the plain of the gap.

[mazeroth]

Those are the correct tweeters, the 269-702. The reason they're not 1db less sensitive but 4db less sensitive is because at 4 ohms and 2.83v the tweeters are actually getting ~2x the power the NSBs are, so it's not really fair. If it was a 1w/1m sensitivity then it would hold true, but it's not. I hate when they use 2.83v ratings.

I might have to look into adding more drivers. I do have 96 NSBs and 128 of the 269-702 tweeters. A few more couldn't hurt

[cjd]

Originally posted by mazeroth
Those are the correct tweeters, the 269-702. The reason they're not 1db less sensitive but 4db less sensitive is because at 4 ohms and 2.83v the tweeters are actually getting ~2x the power the NSBs are, so it's not really fair. If it was a 1w/1m sensitivity then it would hold true, but it's not. I hate when they use 2.83v ratings.

I might have to look into adding more drivers. I do have 96 NSBs and 128 of the 269-702 tweeters. A few more couldn't hurt

You can match drivers of different impedances using the 2.83V/1M measurements - you can't with 1W/1M measurements. I'm not sure why 1W/1M would be preferable. Or I'm completely remembering stuff wrong.

You *can* do a 1:1 on the tweeters, but the power handling gain from pairing them up may be beneficial. You can't really damage the NSBs in use. But then, lines with 48 NSBs each would be, well... interesting.

C

[mazeroth]

cjd, I think you have your 2.83v and 1w/1m backwards

Or am I wrong? LoL!

[cjd]

An amp is a voltage source, no?

I also know that many successful designs have been made using the files straight from PE (after, minimally, a Hilbert transform to "fix" the phase data, and often after modeled baffle interaction, etc.)...

Gotta go find a post I know exists somewhere on this very topic now.

C

[mazeroth]

Thought I’d post a picture of how the “Wall of Sound” looks right now. I asked my brother to take a picture of it and he sent this tiny one, but I guess it’s better than nothing.

Currently using a 1st order and it sounds SO much better than just the woofers full-range. We did a balance test with the woof+tweet on the left vs. the woofers only on the right. No contest. We also don’t listen to it loud (t-amp about ¼ volume) so I don’t think I’m going to add any more drivers. I may add a small resistor on the woofers because I think they’re a tad bit overpowering, but not bad.

Below the speakers on the left is our 4-channel mixer for when we play drums+bass+guitar. We put a ¼” jack in the wall behind the mixer so the mixer headphone out can plug into the wall. That ¼” jack daisies out to 4 ¼” jacks on the right in the picture so we can have 4 headphones plugged into the wall at once. We can practice at 1am in the morning and no one can hear us! It’s awesome!

Thanks again for all the input, even though we went the cheap route. I’ll keep you updated if we make any changes. The only thing I’m considering is adding a small woofer because sub 100hz isn’t really there all that much.