Hi, this is my buildthread about the two Johnnysubs I've just started to build. The Johnnysub is another size of the Martysub. http://www.avsforum.com/forum/155-diy-speakers-subs/1657489-johnnysub.html
I now have a SVS PC12 plus which I bought about 10 years ago. The hometheater room I have is small, only 11.8x9.3 feet.
As I live in Sweden and we use the metric system and it seems like we have a little difference in mdf board sizes so I had to change the size a little.
The converted cutlist to the metric system.
A top/bottom 2' by 2'= 605x605 mm
B sides 2 by 32 = 605x810 mm
C back 2 by 30.5 = 605x772mm
D port bottom 2 by 20,75= 605x522 mm
E port back 2 by 20 = 605x503mm
F bottom rails 2.5x20,75 = 64x522mm
G back rails 2.5x23,25=64x586mm
H front baffles 2x27.25= 605x689mm
I've bought two SI18D4 which will be powered by the Inuke 3000DSP.
Finally found tapatalk, an app for the ipad which seems to be able to post pictures, we'll see how it goes.
Bottom, sides and back glued and screwed togheter. I'm doing both subs at the same time.
Rails done.
The three screwdrivers, good to have when you're drilling, countersinking and screwing.
The ports being painted, testing the paint I bought, read about people having trouble getting good results with the new waterbased paints on mdf. Don't know how it is in the US, but here that's all you can buy now. That's the white primer by the way, black is already on, have no picture of it yet though.
Found some leftover oak shelf to have at the back of the baffle to get the screws to sit good.
Thanks Gamecock, it's going slow but it's going forward
The ports are done.
Started bracing too, usling the window bracing an I'll be putting some bracing around the driver too.
Used a fast drying glue for the bracing, you only have to hold the bracing for ten seconds, "Pattex no more nails" is the name of it, really good when you don't have a nailgun.
Some progress, put some of the foam in. Is the foam too close to the ports in the back?
I'm doing more bracing from the port back to the baffle, that's why there's no foam on the port back.
I'd even consider cutting that piece of foam in half. Interfering with the airflow will outweigh any benefits it has. I like the extra ring for the screws to bite into.
Started up the Inuke 3000 dsp and thought I'd configure it so it's ready. From what I've read the Johnnysub is tuned to about 19.5hz. I've set the hpf to 20hz for both channels with 12db butterworth, and I've chosen the dual mono mode. Anything else I should do as a start? Should I set the peak limiter to something? I'll be running two SI18D4.
Looking good! I'm thinking of building the same- dual johnny's, I've had the drivers for over a month, but no time to build- but I'm following this and interested in the final result.
Finally finished the gluing, but it seems like I have some work to do with sanding the top...
The first one isn't that bad, I can fix that with the router
But this one need some serius sanding..
Should I put foam under the top too? Totally miscalculated how much I would use, got about twice as much, but I'm happy that was the biggest mistake so far..
It has been a while since my last update, so here are some photos of the progress.
Made a frame which I'll cover with some cloth to protect the SI18. I did put some neodym magnets in the frame and the box. Covered the holes for the sanding.
After painting the primer.
The connectors and cables are done.
After two layers of matt black paint. Not dry yet though. It's not perfect but good enough.
It has been a while since my last update, so here are some photos of the progress.
Made a frame which I'll cover with some cloth to protect the SI18. I did put some neodym magnets in the frame and the box. Covered the holes for the sanding. View attachment 373178
Great work. I like the way you did the front to back bracing. I plan to do that in a future build. Also, the oak pieces should give the speaker screws plenty to sink their teeth into.
Thanks, yes it felt really good with that bracing backing up the front. Thought about that I should have made some holes in the "window bracing" so It wouldn't take so much space. But then it was to late, I had already glued it in the box. Yes the oak is very hard, even had smoke coming from the drill holes when drilling in it [emoji3]
Finally finished with sound from the subs so all is working. It's late here now, so I can't calibrate or play loud. Will have to wait until after work tomorrow [emoji52]
Finally finished with sound from the subs so all is working. It's late here now, so I can't calibrate or play loud. Will have to wait until after work tomorrow [emoji52] View attachment 376810 View attachment 376818
I think they look great. I know you're limited on placement, but you should read these articles just the same. You're going to get some lobing where they are.
Yes, can't complain about the fit, don't know what I would have done if I had measured that wrong so it wouldn't fit. Really felt good when the last one slided in place [emoji2]
Hello there again, I've been so busy with work and christmas and everything else so I haven't had that much time so I could test the subs as I wanted to. Two weeks ago I also catched a cold, that after a few days made my eardrums burst. So I'm still on penicillin but the hearing is not ok yet, apperently it could take a few weeks until all is ok again.
I did run calibration first with the Antimode sub calibration that I have and after that the audessey calibration. I thought that it sounded good but I was expecting it to be better. But as I wrote before I haven't had the time to play with it as much as I would like, and it can be either the antimode or the audessey that's doing something bad. Or maybe I've done something...
I've also ordered a microphone from minidsp so I can use REW and do some measuring. The good thing is that my ears don't have to be 100% to do some measuring [emoji1]
Hi again, the UMIK-1 has arrived.
I've done some measuring and testing with REW for a few hours now following the "Basic REW for INUKE" thread by chalugadp. Very good tutorial, thanks chalugadp!
One difference that I made when measuring is that I did the measuring between 15-120hz.
I also inserted some pictures on the inuke config. I did put in the suggested (some not exactly the same with the limitations that's in the eq of inuke) eq filters in the inuke but it didn't do that much. Also tested with just one sub, and the curve was basically the same.
Is the length in the receiver setting between the subs and the mic important for the REW measuring? I didn't change that from what audessey calculated.
I didn't think of testing with the Antimode sub EQ, or audessey on, too tired maybe, as it's in the middle of the night here....
Suggestions and comments are greatly appriciated!
Most of the EQ filters in the EQ tab are not active. They must be yellow like "Filter 1". Im betting thats the reason your before and after is almost the same.
Thanks, I didn't notice that they where off [emoji4]
I just did a quick measure again but it had small effect on the curve. I'll upload a picture later.
Just realized that I've been measuring the front speakers... [emoji1] I had the receiver on "direct" which apperently didn't direct the lfe to the subwoofers.
Here's new pictures.
But why is it just one EQ filter suggested? And not where the dip around 80hz is?
Generally it is a good idea not to boost a null or a dip in the frequency. Moving the subs around to correct the dip is the preferred way to address the dips. When boost gets added to frequencies it makes the amp work a lot harder and may not fix the problem. A good rule of thumb is to address the peaks in the response with EQ and not the dips and to have as few filters in place as possible (1 is a great way to start out). Using a lot of EQ filters to tame peaks will lower the output of the sub so the gain will have to be turned up in order to compensate.
It may also be the crossover on your receiver causing the dip. You may want to check that.
Your response looks pretty good overall. You could probably achieve a nice house curve.
It'll probably just require some tweaking, maybe with placement, or target level to get it just right, it'll just take a little time.
Edit: By the way, nice build!
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