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post #511 of 1287 Old 02-20-2012, 05:41 AM - Thread Starter
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What throw distance did you end up with?

FYI at 14' throw 120" diag 2.37 is the maximum i could get....

15 feet from lens to screen. That put it right in the sweet spot of the zoom for 120" wide scope and 51" tall 16:9. Something like 17 and 19 FL respectively.

You're using a 4000, right? Are they lenses differently?
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post #512 of 1287 Old 02-20-2012, 06:14 AM
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I'll do my best to get a vid out this week! I want to get one up as much as you want to see one. Thanks for the compliments.

I have pretty much decided on a Panasonic pt-ae7000u despite its having 3D. The price is barely approachable, bright, good contrast, and my company is a Panasonic dealer so I should be able to get a small discount off MAP.

I too will probably use a Chief mount (again, we're dealers). I need to read up on this a lot more. I'm not sure how to install the thing blind through drywall. I don't know if I should cut out the ceiling, install plywood blocking, then reinstall drywall or what.

If you want to hang it in an exact position, then the best way is indeed to open up and secure blocking between the joists. However, if you don't want to tear into the ceiling and since the total weight load of the projector and mount being less than 50 pounds, then just secure it with either METAL toggle bolts through the drywall or the higher-end plastic zip toggle (called a Snaptoggle).

But have you checked your ceiling joist position in relation to the depth of the projector? Given that your joists are probably positioned from left to right, I am sure you can play within the range of the throw distance to secure at least two screws directly into the studding without opening the ceiling, save for the power and signal wire box. I would still use thin metal toggles for the two rearward mounting holes if the fronts are secured in studding. Don't forget to account for the physical lens offset of that Panny!
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post #513 of 1287 Old 02-20-2012, 06:24 AM
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Jon - I just noticed something on your latest picture - the return air duct on the right hand of the stage which appears to be partially blocked by the stage. Do you have plans to move this up so the grate can be opened and the filters changed? I can also imagine the partial blockage adding a bit of air turbulence noise.

By the way, are you now officially done with the upstairs family room and back on the theater project?
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post #514 of 1287 Old 02-20-2012, 06:28 AM
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Not to hijack your thread, but here is a link to those Snaptoggler bolts. Cool little installation animation video is also on this page:
http://www.toggler.com/products/snaptoggle/overview.php

Should be available at Lowe's, HD or most hardware stores. Really a superior product in design and holding power.
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post #515 of 1287 Old 02-20-2012, 07:32 AM
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Originally Posted by jdanforth View Post


15 feet from lens to screen. That put it right in the sweet spot of the zoom for 120" wide scope and 51" tall 16:9. Something like 17 and 19 FL respectively.

You're using a 4000, right? Are they lenses differently?

IDK how much different they are, close cousins for sure. I dont think youll be dissappointed with that setup.

Have you decided on an aspect?

Id love to demo for you if you want to see a 120 2.37 in action......

Also screen construction: Iive got a couple tricks up my sleeve which might be of value.....
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post #516 of 1287 Old 02-20-2012, 08:29 PM
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Those are for when my neighbors hear the 20Hz at 120dB!

Awesome!!!
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post #517 of 1287 Old 02-20-2012, 09:15 PM
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If you want to hang it in an exact position, then the best way is indeed to open up and secure blocking between the joists. Given the total weight load of the projector and mount being less than 50 pounds and needing to secure it with 4 screws I would still suggest using METAL toggle bolts through the drywall or the higher-end plastic zip toggle (called a Snaptoggle).

However, have you checked your ceiling joist position in relation to the depth of the projector? Given that your joists are probably positioned from left to right, I am sure you can play within the range of the throw distance to secure at least two screws directly into the studding without opening the ceiling, save for the power and signal wire box. I would still use thin metal toggles for the two rearward mounting holes if the fronts are secured in studding. Don't forget to account for the physical lens offset of that Panny!

If you look at mine (and ignore the curtain wall), we opened up the ceiling (~12"x16"), installed blocking between the joists then replaced the sheetrock and taped/muddled the joints. Overall it probably took less than an hour and gives us a really firm setting from which to mount everything (the joists run parallel to the curtain wall so we didn't have a choice).
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post #518 of 1287 Old 02-21-2012, 05:52 AM
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How bout some more photos?

The "Twinseltown" Theater
Construction Thread
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post #519 of 1287 Old 02-21-2012, 06:34 AM
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How bout some more photos?

Actually we want the videos!
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post #520 of 1287 Old 02-21-2012, 06:44 AM
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Meh! I want both!

Dude, are you made of leprechauns? Cause that was awesome!

The Plains Theater Has Begun
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post #521 of 1287 Old 02-21-2012, 08:49 PM - Thread Starter
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Subwoofer drivers came in today! I installed one and have been enjoying the hell out of it. I've got some grounding hum though. it's real low but ever-present. If it isn't fixed I'll drive myself crazier.

I disconnected everything from the processor except the sub and the hum remained. If I disconnect the RCA from the processor to the sub amp the hum disappears. The sub amp and processor are plugged into the same outlet. I also tried changing the interconnect. Can you tell this isn't my first ground loop problem? . I'm open to suggestions!

This may be related but I'm not sure. This is my first home brew sub. The driver has dual voice coils but I only connected one. Is that a problem? Should I connect both? That would mean 2 channels per sub but I only have a single sub output on the Meridian 568.2.

Thanks for all of your posts recently. I will respond to then tomorrow, hopefully. Work and Maker Faire work are keeping me REALLY busy! I'm still aiming to deliver a new video this week, however!
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post #522 of 1287 Old 02-21-2012, 09:08 PM
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Couple things you haven't mentioned trying. Disconnect all the sources/cables and any other components from the receiver so that all you have remaining is the sub interconnect and the other speakers. If you still have the hum disconnect your other speakers. Assuming you can make the hum go away start plugging things in one at a time. If the hum doesn't go away you can try lifting the ground of first the sub amp then the receiver.
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post #523 of 1287 Old 02-22-2012, 12:26 AM
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Great stuff Jon. I've just caught up reading your thread again. Nice front soundstage. Those beasts will surely keep you PINNED in your seat
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post #524 of 1287 Old 02-22-2012, 03:11 AM
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The first thing I would do is use a heavy duty power cord / power strip to plug the equipment into a number of different outlets to see if the problem still persists. If it does, then I would look to plug this stuff into a completely different circuit to see if the problem still persists.

I would also remove the receptacle itself and verify the grounding and its overall physical condition.

Big's suggestion to lift the ground component by component using a simple 50 cent ground lifter may help you to identify the affected equipment but would not be a permanent solution. Lifting the ground is dangerous and is a definite electrocution hazard.

I assume you will be using a power protection device for your system. Most of these filter the power by internally balancing the power back and forth several times to eliminate most external noise. If you have checked everything else out with your house electrical system and find no problems, then I would plug everything into a power protection / isolation device to see if this solves your issue. But if you have OCD tendencies like me, I would still try to isolate the route cause of the noise coming into your system. I would be very interested to know what you find out.
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post #525 of 1287 Old 02-22-2012, 04:55 AM
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Quote:
Originally Posted by jdanforth View Post

Subwoofer drivers came in today! I installed one and have been enjoying the hell out of it. I've got some grounding hum though. it's real low but ever-present. If it isn't fixed I'll drive myself crazier.

I disconnected everything from the processor except the sub and the hum remained. If I disconnect the RCA from the processor to the sub amp the hum disappears. The sub amp and processor are plugged into the same outlet. I also tried changing the interconnect. Can you tell this isn't my first ground loop problem? . I'm open to suggestions!

This may be related but I'm not sure. This is my first home brew sub. The driver has dual voice coils but I only connected one. Is that a problem? Should I connect both? That would mean 2 channels per sub but I only have a single sub output on the Meridian 568.2.

Thanks for all of your posts recently. I will respond to then tomorrow, hopefully. Work and Maker Faire work are keeping me REALLY busy! I'm still aiming to deliver a new video this week, however!

ground loops are fun double check your cables and make sure they connect tight at the connectors. I recently got some cables from monoprice which were loose and developed a hummmmm. i had to bend the interconnects to tighten them.

Both subs or just one?

Suspect anything with a three prong plug. ive had the most success plugging everything into same outlet. Funny thing i didnt notice a humm when we played with the MFW. Whats different now besides driver?

As far as the driver you definitly want both voice coils hooked up. They are 8ohms each so hookup parallel for a 4ohm load to amp. Running 8 ohms on one VC is less than half power.
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post #526 of 1287 Old 02-22-2012, 05:07 AM
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I ended up using a ground loop isolator in my system. Spent months tracking it and ended up going that route. It did cause me to raise my input signal by roughly 4db, but otherwise it didn't effect the FR. I'd rather have it out of the chain, none the less.

The "Twinseltown" Theater
Construction Thread
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post #527 of 1287 Old 02-22-2012, 07:19 AM
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Originally Posted by tony123 View Post

I ended up using a ground loop isolator in my system. Spent months tracking it and ended up going that route. It did cause me to raise my input signal by roughly 4db, but otherwise it didn't effect the FR. I'd rather have it out of the chain, none the less.

Hey Tony did you put the isolator on the sub cable? Which isolator? Ive seen the ones for coax but not familiar with ones for rca.......
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post #528 of 1287 Old 02-22-2012, 12:33 PM - Thread Starter
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Originally Posted by TMcG View Post

If you want to hang it in an exact position, then the best way is indeed to open up and secure blocking between the joists. However, if you don't want to tear into the ceiling and since the total weight load of the projector and mount being less than 50 pounds, then just secure it with either METAL toggle bolts through the drywall or the higher-end plastic zip toggle (called a Snaptoggle).

But have you checked your ceiling joist position in relation to the depth of the projector? Given that your joists are probably positioned from left to right, I am sure you can play within the range of the throw distance to secure at least two screws directly into the studding without opening the ceiling, save for the power and signal wire box. I would still use thin metal toggles for the two rearward mounting holes if the fronts are secured in studding. Don't forget to account for the physical lens offset of that Panny!

Thanks! I'm sure that I can find at least two mounting points along the joist and I can use leftover SnapToggles for the others. I used SnapToggles to mount the soffits on the two sides that didn't run with the joists.

I'm wondering too about vibration from the floor above. I'm worried about people clomping around up in the kitchen shaking the projector. I guess there's not much to be done about that except see if the problem exists and then use a vibration reduction mount if necessary.
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post #529 of 1287 Old 02-22-2012, 12:34 PM - Thread Starter
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Jon - I just noticed something on your latest picture - the return air duct on the right hand of the stage which appears to be partially blocked by the stage. Do you have plans to move this up so the grate can be opened and the filters changed? I can also imagine the partial blockage adding a bit of air turbulence noise.

By the way, are you now officially done with the upstairs family room and back on the theater project?

Quite right. There is an intake there but it is actually really accessible. I've been changing the filter in it regularly. I'm planning to remove the metal cover entirely when I build the minimalist screen wall. It will still be accessible by removing a panel of the screen wall. Good eye!
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post #530 of 1287 Old 02-22-2012, 12:36 PM - Thread Starter
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Originally Posted by NicksHitachi View Post

IDK how much different they are, close cousins for sure. I dont think youll be dissappointed with that setup.

Have you decided on an aspect?

Id love to demo for you if you want to see a 120 2.37 in action......

Also screen construction: Iive got a couple tricks up my sleeve which might be of value.....

I've decided to stick with 2.35:1. I'm almost positive that I'll go DIY build with Seymour fabric.

I've seen Tony123's 2.35 with the 4000 but I'd still love to come see yours too! Road trip!
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post #531 of 1287 Old 02-22-2012, 12:41 PM - Thread Starter
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Quote:
Originally Posted by tony123 View Post

How bout some more photos?

Quote:
Originally Posted by BIGmouthinDC View Post

Actually we want the videos!

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Originally Posted by J_P_A View Post

Meh! I want both!

I'm doing my best!
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post #532 of 1287 Old 02-22-2012, 12:42 PM - Thread Starter
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Quote:
Originally Posted by Expat444 View Post

If you look at mine (and ignore the curtain wall), we opened up the ceiling (~12"x16"), installed blocking between the joists then replaced the sheetrock and taped/muddled the joints. Overall it probably took less than an hour and gives us a really firm setting from which to mount everything (the joists run parallel to the curtain wall so we didn't have a choice).

That's not a bad idea, actually. Opening up the ceiling would be damned convenient for running some wiring anyway. I'm picturing that you would do it like you would with a drywall patch: cut out a rectangle to halfway along the stud, attach the blocking, and then screw the DW right into the blocking? Hmmm! Thanks!
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post #533 of 1287 Old 02-22-2012, 12:44 PM - Thread Starter
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Originally Posted by BIGmouthinDC View Post

Couple things you haven't mentioned trying. Disconnect all the sources/cables and any other components from the receiver so that all you have remaining is the sub interconnect and the other speakers. If you still have the hum disconnect your other speakers. Assuming you can make the hum go away start plugging things in one at a time. If the hum doesn't go away you can try lifting the ground of first the sub amp then the receiver.

Actually, I did try unplugging everything. I wasn't very clear in my post that I wrote last night on my phone.

The only thing connected to the 568.2 was the power and the sub-out cable and I still heard the hum. I also tried different sub-out cables at this point with no improvement.
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post #534 of 1287 Old 02-22-2012, 12:45 PM - Thread Starter
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Originally Posted by Bobbejaan View Post

Great stuff Jon. I've just caught up reading your thread again. Nice front soundstage. Those beasts will surely keep you PINNED in your seat

Thanks! It's starting to really sound like a good room now!
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post #535 of 1287 Old 02-22-2012, 12:48 PM - Thread Starter
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Originally Posted by TMcG View Post

The first thing I would do is use a heavy duty power cord / power strip to plug the equipment into a number of different outlets to see if the problem still persists. If it does, then I would look to plug this stuff into a completely different circuit to see if the problem still persists.

Hmm, OK. I have tried multiple outlets but not multiple circuits. I'll give that a bang tomorrow night, probably.

Quote:
Originally Posted by TMcG View Post

I would also remove the receptacle itself and verify the grounding and its overall physical condition.

Does it count that it tests out fine with my circuit tester gizmo?

Quote:
Originally Posted by TMcG View Post

Big's suggestion to lift the ground component by component using a simple 50 cent ground lifter may help you to identify the affected equipment but would not be a permanent solution. Lifting the ground is dangerous and is a definite electrocution hazard.

Thanks for confirming that. I had thought that was the case and have been reluctant to use it as a permanent solution. I was planning to try it out to identify the offending device though.

Quote:
Originally Posted by TMcG View Post

I assume you will be using a power protection device for your system. Most of these filter the power by internally balancing the power back and forth several times to eliminate most external noise. If you have checked everything else out with your house electrical system and find no problems, then I would plug everything into a power protection / isolation device to see if this solves your issue. But if you have OCD tendencies like me, I would still try to isolate the route cause of the noise coming into your system. I would be very interested to know what you find out.

OCD Tendencies on standby... my hand is already shaking a little bit!

I'm going to have all of the stuff plugged into some kind of sequencer but it's tricky (read:expensive) to protect everything since all of the speakers are individually powered.
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post #536 of 1287 Old 02-22-2012, 12:57 PM - Thread Starter
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Quote:
Originally Posted by NicksHitachi View Post

ground loops are fun double check your cables and make sure they connect tight at the connectors. I recently got some cables from monoprice which were loose and developed a hummmmm. i had to bend the interconnects to tighten them.

Both subs or just one?

Suspect anything with a three prong plug. ive had the most success plugging everything into same outlet. Funny thing i didnt notice a humm when we played with the MFW. Whats different now besides driver?

As far as the driver you definitly want both voice coils hooked up. They are 8ohms each so hookup parallel for a 4ohm load to amp. Running 8 ohms on one VC is less than half power.

No change except driver and physical location of sub cabinet. The hum is quiet. I'm not surprised that we didn't hear it when you were here.

Regarding wiring, should I just daisy chain positive to positive and negative to negative on the driver?
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post #537 of 1287 Old 02-22-2012, 12:57 PM
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I'm wondering too about vibration from the floor above. I'm worried about people clomping around up in the kitchen shaking the projector. I guess there's not much to be done about that except see if the problem exists and then use a vibration reduction mount if necessary.

Yes, unfortunately movement is movement and it cannot be easily helped. My experience with dampened mounts is that they work to a certain extent and are very expensive. They just don't compensate very well with the flex of the floor.

I know what I am about to suggest is a bit of work, but in true Maker's Faire style, I will offer it here:

Open a hole in the drywall with your ideal projector location. attach two or three layers of OSB / Green Glue on both sides of the vertical plane of the joist. Make another assembly out of 2x4s and decoupling clips to support a 3/4" square of plywood sized large enough for your projector mount. Mount this assembly at a height even with the lower edge of your existing joists. Replace the drywall (maybe a spot of GG as well) and mount the projector to the 3/4" decoupled plywood blocking just beneath. This is probably more effort than it is actually worth, but there are very, very few ways to minimize and dampen vibration from the floor above without adequate decoupling. At my last house I had this EXACT problem with the kitchen above and my SOny Qualia 004 projector. I took a slightly different approach in attaching two layers of 3/4" plywood and green glue to the underside of the subfloor above. I then mounted the projector to this dual 3/4" ply sandwich and used a short extension post to get the projector through the drywall of the ceiling. It ended up being a very clean install and worked at removing a good deal of the vibration, but it was never perfect.

Good luck!
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post #538 of 1287 Old 02-22-2012, 12:59 PM - Thread Starter
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Quote:
Originally Posted by tony123 View Post

I ended up using a ground loop isolator in my system. Spent months tracking it and ended up going that route. It did cause me to raise my input signal by roughly 4db, but otherwise it didn't effect the FR. I'd rather have it out of the chain, none the less.

What if I were just to drop the shield from one side of an RCA interconnect so it acts as drain? What kind of isolator do you suggest?
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post #539 of 1287 Old 02-22-2012, 01:33 PM
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Originally Posted by jdanforth View Post

Hmm, OK. I have tried multiple outlets but not multiple circuits. I'll give that a bang tomorrow night, probably.


Does it count that it tests out fine with my circuit tester gizmo?


Thanks for confirming that. I had thought that was the case and have been reluctant to use it as a permanent solution. I was planning to try it out to identify the offending device though.



OCD Tendencies on standby... my hand is already shaking a little bit!

I'm going to have all of the stuff plugged into some kind of sequencer but it's tricky (read:expensive) to protect everything since all of the speakers are individually powered.



Going to different outlets will help you find out if it is that outlet. Going to different circuits will help you find out if it is that circuit. If the outlet tests OK and you are still getting the same hum on a different receptacle then I wouldn't bother inspecting the current receptacle.

I just thought of one other thing - are your lights and this receptacle on the same feeder circuit? If so, try turning the lights out to see (pun intended) if you still hear the hum.

Getting into things a bit further would be looking at what could be putting that noise IN to your electrical system.

These problems are unfortunately some of the most difficult to diagnose. You have enough high-end and very expensive equipment to merit a dedicated circuit(s) for your system without question. My OCD tendencies tell me that I would run two new 20 amp circuits to my equipment closet and use Powerbridges to bring clean, isolated, filtered and protected power to each one of your DSP speakers and your projector. Plus there is little chance for any difference in ground potential. The question is how easily is this accomplished from your equipment closet to your electrical panel and does your panel have any additional room for these two circuits. I don't know if I just helped you, pissed you off or have you in tears!!
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post #540 of 1287 Old 03-06-2012, 04:27 PM
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Yo whats up lately bro?

Still going in circles with ground loops?

Semi OT: Maker's Fair Update?

Been spending too much time with that INSANE BASS!?
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