LMS Ultra Owners -- Is my Sub Faulty? (Updated Sep 2, 2012 - Bad Amp) - Page 6 - AVS Forum
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post #151 of 158 Old 09-05-2012, 01:42 PM - Thread Starter
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Originally Posted by edoggrc51 View Post

I totally lucked out on the eD boxes, especially considering how things are going with them right now. The cabs are built like bricks, if i recall correctly they weighed in at 122lbs (or was it 112lbs??).

Jesus man! I though I remember reading 76lbs without the sub. So your rocking 800lbs of subs/cabinets...
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post #152 of 158 Old 09-05-2012, 02:17 PM
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Originally Posted by imagic View Post

I'm sorry about that comment, totally uncalled for.

Thanks

I understand.

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post #153 of 158 Old 09-05-2012, 02:54 PM
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I'm glad this worked out (minus the amp of course)

If you don't have a backup amp, then one really good way to differentiate amp issues from coil rubbing issues is to play a sinwave into your system at a higher frequency. The cone movement will be a lot less and you should be able to isolate the two symptoms.

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post #154 of 158 Old 09-05-2012, 03:05 PM
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Originally Posted by popalock View Post

Jesus man! I though I remember reading 76lbs without the sub. So your rocking 800lbs of subs/cabinets...

Yes sir! cool.gif

These subs were the biggest pain in the butt to move around/place. They're just so so heavy!...........But well worth the expense/hassle. smile.gif
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post #155 of 158 Old 09-06-2012, 07:37 AM
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I don't know if this helps, but after this whole thread turned around I started messing with my Crown XTi-1000 and some subs. I can't measure voltages and watts and all that (yet), so I have to go with how the system reacted to different loads and impedance when playing the same sine waves and/or test tracks. In a nutshell, the lower the impedance, the cleaner the power... but 'failure' occurs through hard clipping which sounds distinctly mechanical (clanking in my case)... that's the clipping that destroys speakers in nanosecond. The higher the impedance, the softer the clipping - at 8ohms it's been replaced by THD and dynamic compression which gives the (false) impression of more power because you can still turn the volume up and it seems to provide more power even than 2 ohms but of course it's just getting dirtier... very fast. I have four DVC drivers, two are 2 ohm VC and two are 4 ohm VC, so I wired the whole thing to run with a combined impedance of 3 ohms per channel, and it is by far the cleanest and most powerful configuration I've had... good resistance to clipping, no distortion before that clipping manifests... and with a modded fan the amp is staying cool even on tougher bass sequences. I do need to step up my amp game, in fact I'm sure I need to do that before I buy any more drivers at all. Something with at least double the power of the XTi-1000 (like the Xti-4002). Gotta admit, I'm partial to Crown I cannot overstate how much abuse this XTi-1000 has taken over the past 5 years. I take its reliability for granted.

I wonder if you could audition an XTi-6002 and see how it stacks up to the clone? One thing I know for sure, the Kicker Solo-X 18" is no longer something I am looking at, I can't afford to amp that driver properly so why bother. Instead I'm going to work with multiple Polk MM15DVC because they are very efficient and inexpensive and the math really works in their favor using amps I can afford... plus I've used one long enough that I feel very comfortable with it - good SQ, very resilient. It's certainly the opposite of those mega-woofers but it is very good in its own way. As appealing as 'crazy-ass 18" solid-stone woofer' is to me, I finally ran into a WAF wall on that one.

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post #156 of 158 Old 09-06-2012, 08:36 AM - Thread Starter
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Originally Posted by imagic View Post

I don't know if this helps, but after this whole thread turned around I started messing with my Crown XTi-1000 and some subs. I can't measure voltages and watts and all that (yet), so I have to go with how the system reacted to different loads and impedance when playing the same sine waves and/or test tracks. In a nutshell, the lower the impedance, the cleaner the power... but 'failure' occurs through hard clipping which sounds distinctly mechanical (clanking in my case)... that's the clipping that destroys speakers in nanosecond. The higher the impedance, the softer the clipping - at 8ohms it's been replaced by THD and dynamic compression which gives the (false) impression of more power because you can still turn the volume up and it seems to provide more power even than 2 ohms but of course it's just getting dirtier... very fast. I have four DVC drivers, two are 2 ohm VC and two are 4 ohm VC, so I wired the whole thing to run with a combined impedance of 3 ohms per channel, and it is by far the cleanest and most powerful configuration I've had... good resistance to clipping, no distortion before that clipping manifests... and with a modded fan the amp is staying cool even on tougher bass sequences. I do need to step up my amp game, in fact I'm sure I need to do that before I buy any more drivers at all. Something with at least double the power of the XTi-1000 (like the Xti-4002). Gotta admit, I'm partial to Crown I cannot overstate how much abuse this XTi-1000 has taken over the past 5 years. I take its reliability for granted.

I wonder if you could audition an XTi-6002 and see how it stacks up to the clone? One thing I know for sure, the Kicker Solo-X 18" is no longer something I am looking at, I can't afford to amp that driver properly so why bother. Instead I'm going to work with multiple Polk MM15DVC because they are very efficient and inexpensive and the math really works in their favor using amps I can afford... plus I've used one long enough that I feel very comfortable with it - good SQ, very resilient. It's certainly the opposite of those mega-woofers but it is very good in its own way. As appealing as 'crazy-ass 18" solid-stone woofer' is to me, I finally ran into a WAF wall on that one.

Haaha… So AVS isn’t going to see its first bolder build? Hey, WAF is a part of life… We all face it at some point. Especially those who like to push the limits. Your current setup looks good man! For the price of one ultra you could get a lot of decent options in multiples.

Ok, I have a few questions for you regarding your post above… You indicate that you have four drivers that you are pushing with your XTi-1000. Two are 2ohm DVC and the other two are 4ohm DVC. That’s how I interpret your post, is that correct?

Are all four subs the same drivers (power rating, etc…) but with two different VC impedances?

The XTi-1000 is a single channel amp… I’m not sure how you have wired the VC’s of your subs, but if you aren’t already aware, they are seeing different power from the amp. While you calculated that your amp sees a “3 ohm” load, your 2ohm DVC subs are getting more (or less depending on how you have the VC wired) power than your 4ohm DVC subs. So you are physically pushing one type (pair) of subs harder....

Make sense? I don’t recommend mixing multiple VC impedances on the same channel. Now, if you had a 4ohm SVC and a 2ohm DVC that you could series to 4ohm, then each sub would see the same power and be pushed at the same level. I personally wouldn’t go that route unless I absolutely had too for some weird reason?

Just keep that in mind my friend. Don’t go blowing $hit up… Or if you do, make sure it’s well documented with a video.
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post #157 of 158 Old 09-06-2012, 08:54 AM
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I'm mixing a Polk wired for 8 ohm with a Kicker wired for 4 ohms (Kicker is 2 ohm DVC), wired parallel for each channel. Yes the Kicker gets more power but it is also less efficient. It balances and my amp likes it. Regular speaker mix-and-match drivers through a crossover, but in the end there is an unbabanced, asymmetrical load seen by the amp so I'm not sweating what my sub is presenting the amp. Blowing up a Crown is really hard to do.

I tried every balanced, symmetrical combination imaginable before deciding to do this. It's just time for another amp, plain and simple.

The XTi-1000 is a stereo amp, rated at 700/w channel 2 ohms or 1400/w 4 ohm bridged

EDIT I I just checked and my wiring is actually presenting the amp with a 2.67ohm load per channel. It just seems to be the sweet-spot for this amp.
Quote:
Originally Posted by popalock View Post

Haaha… So AVS isn’t going to see its first bolder build? Hey, WAF is a part of life… We all face it at some point. Especially those who like to push the limits. Your current setup looks good man! For the price of one ultra you could get a lot of decent options in multiples.
Ok, I have a few questions for you regarding your post above… You indicate that you have four drivers that you are pushing with your XTi-1000. Two are 2ohm DVC and the other two are 4ohm DVC. That’s how I interpret your post, is that correct?
Are all four subs the same drivers (power rating, etc…) but with two different VC impedances?
The XTi-1000 is a single channel amp… I’m not sure how you have wired the VC’s of your subs, but if you aren’t already aware, they are seeing different power from the amp. While you calculated that your amp sees a “3 ohm” load, your 2ohm DVC subs are getting more (or less depending on how you have the VC wired) power than your 4ohm DVC subs. So you are physically pushing one type (pair) of subs harder....
Make sense? I don’t recommend mixing multiple VC impedances on the same channel. Now, if you had a 4ohm SVC and a 2ohm DVC that you could series to 4ohm, then each sub would see the same power and be pushed at the same level. I personally wouldn’t go that route unless I absolutely had too for some weird reason?
Just keep that in mind my friend. Don’t go blowing $hit up… Or if you do, make sure it’s well documented with a video.

Find out more about Mark Henninger at www.imagicdigital.com
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post #158 of 158 Old 09-06-2012, 09:03 AM
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The WAF was about the budget, not the gear so yes AVS will see the Solo-X build, hopefully this year but not next week. I still have a use for a strictly-infrasonic mega-brute sub and I even have some clients/friends who would buy such a thing for their studio if they could demo it and it worked.
Quote:
Originally Posted by popalock View Post

Haaha… So AVS isn’t going to see its first bolder build? Hey, WAF is a part of life… We all face it at some point.
Just keep that in mind my friend. Don’t go blowing $hit up… Or if you do, make sure it’s well documented with a video.

Find out more about Mark Henninger at www.imagicdigital.com
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