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Crown XLS Drivecore amps & subsonic content (v. we have a problem Houston?) - Page 2

post #31 of 91
Thread Starter 
The flashing lights are the red thermal lights, not the clip lights. In an interesting turn of events my XLS 2500 arrived early so I will be testing it later this evening.
post #32 of 91
Thread Starter 
Okay, so I got my XLS 2500 today. It seems to have a few more dB of headroom than the XLS 1500 before the protection hits.

XLS 2500
Frequency : receiver volume where the protection kicks in
20Hz : no
16Hz : no
15Hz : no
10Hz : -4.5dB
5Hz : -11.5dB
Edited by Stereodude - 12/11/12 at 6:20pm
post #33 of 91
The opening scene of 'Immortals" would throw my iNuke 6000DSP into protection mode, it bothered me so much I returned it and got he XTi-2002, which has proven to be rock-solid with a 2 ohm load. I do think you get what you pay for, marketing specs notwithstanding...especially with tougher loads (extended LFE content on 2 ohm subs).
post #34 of 91
Quote:
Originally Posted by Stereodude View Post

Okay, so I got my XLS 2500 today. It seems to have a few more dB of headroom than the XLS 1500 before the protection hits.

That's why I just opted to get the top of the line one. You can alway dial down the power but can't add it if your amp is running out of juice. I kept a keen eye out and snatched my XLS 2500 for $325 + $25 shipping. The guy had it for only six months (only said he used it a handful of times) and was in mint condition. He had everything that it came with (box, manual, etc...) and also gave me the original sales receipt for it. It's been working great and can't wait to finish my build and put it to real use. What can I say i'm cheap but like to have nice things. biggrin.gif I just bought a 7 or so year old Miele Dishwasher for $50. It was filthy as all can be but it's all cleaned up now and is the nicest dishwasher I've ever seen and looks almost exactly like the new ones on the inside. smile.gif
post #35 of 91
A little off topic here, but related to this and other pro amps...I see all these amps with varying sensitivity like 1v at 4ohm load. Meaning that they are capable of making full power when fed a signal of 1v and driving 4phm load. Does this requirement go up or down as load increases or decreases? Do they require more voltage at 2ohm?
post #36 of 91
Thread Starter 
Quote:
Originally Posted by jayHRC51 View Post

A little off topic here, but related to this and other pro amps...I see all these amps with varying sensitivity like 1v at 4ohm load. Meaning that they are capable of making full power when fed a signal of 1v and driving 4phm load. Does this requirement go up or down as load increases or decreases? Do they require more voltage at 2ohm?
It goes down, but only because the amplifier's power doesn't double each time the impedance is halved.

For example, an amp that can deliver 200W into 8 ohms, 400W into 4 ohms and 800W into 2 ohms would not have any decrease in voltage sensitivity because the output voltage is the same for all 3 loads (40V) and the amp has a maximum fixed amount of voltage gain. An amp that can deliver 200W into 8 ohms, 300W into 4 ohms and 500W into 2 ohms does have a decrease in voltage sensitivity because the output voltage drops (40, 34.6, & 31.6 respectively) and the max voltage gain is fixed.
post #37 of 91
Quote:
Originally Posted by Stereodude View Post

The flashing lights are the red thermal lights, not the clip lights. In an interesting turn of events my XLS 2500 arrived early so I will be testing it later this evening.

I don't know if you're directing this at me, but yes, I know this. I'm stating that they (the clip lights) flickered a bit on WOTW, but I was not getting the regularly flashing thermal lights in tandem like I had before.

James
post #38 of 91
Quote:
Originally Posted by imagic View Post

The opening scene of 'Immortals" would throw my iNuke 6000DSP into protection mode, it bothered me so much I returned it and got he XTi-2002, which has proven to be rock-solid with a 2 ohm load. I do think you get what you pay for, marketing specs notwithstanding...especially with tougher loads (extended LFE content on 2 ohm subs).

I'm considering an XTi 4002 just for this reason, but fear it will be a 55db party fan that I won't be excited about modding.

Althgouh you can adjust the fan in the xti, correct? I'm just assuming it's still quite loud even at the "low/reg" setting.

thanks, don't mean to be OT.

James
post #39 of 91
Actually the fan in the XTi-***2 series is much better than the original XTi. There are three fan profiles, I use 'normal' which actually translates to 'off' most of the time. If the amp handles a huge, extended bass passage the fan will turn on but it's not nearly as loud as the fan on the iNuke - which I modded within the first hour after I got it. I've decided I do not need to do anything about the 2002's fan, unlike my XTi-1000 which was unbearable (and is now fanless, but only doing midrange duty). Also it's a variable speed fan so it only runs full speed if it absolutely must.
Quote:
Originally Posted by mastermaybe View Post

I'm considering an XTi 4002 just for this reason, but fear it will be a 55db party fan that I won't be excited about modding.
Althgouh you can adjust the fan in the xti, correct? I'm just assuming it's still quite loud even at the "low/reg" setting.
thanks, don't mean to be OT.
James
post #40 of 91
^ beautiful, was just watching a review on youtube that said the same. I'm assuming I should be in good shape with my Denon 4311, voltage-wise with that 1.4V input sensitivity- hasn't been an issue with my 1.4 sens xs900 or xls2500.

thanks

James
post #41 of 91
Should be zero issues with input sensitivity.
Quote:
Originally Posted by mastermaybe View Post

^ beautiful, was just watching a review on youtube that said the same. I'm assuming I should be in good shape with my Denon 4311, voltage-wise with that 1.4V input sensitivity- hasn't been an issue with my 1.4 sens xs900 or xls2500.
thanks
James
post #42 of 91
^ good deal, My initial inclination was to pay a few more bucks for the xti line but the fan really scared me away...should have investigated it further. The xls is nice, but again, for pushing these low loads, the xti is almost certainly a superior choice.

James
post #43 of 91
Interesting, I've been wondering and inquiring about these amps LF/ULF aptitude since they hit the scene.


Observations;
This is the way amps are suposed to behave when asked to deliver beyond their means.....unlike others that burn up.

IMO, designing a sytem operational with 2ohm sub loads on amplifier channels is, at best, less than optimal. At worse, a bad idea.

Those mentioning the 2ohm nominal component to this issue are dead on,...as there's likely points on the complex Nyquist whereby the loads dip further down, approaching a dead short.

To properly determine voltage, you must check line voltage under load,...coinciding with demand. Wih minimal load, you're just going to see whatever your service sees.

Don't these amps have some type of voltage correction imunity? If so, they prolly won't behave linearly at the current limits (with a nice predictable roll-off). They'll pump along, relatively immune to line voltage, then suddenly there's nothing left, and the circuit opens protectively. Just speculating.

On a related note;
Subwoofer amps work best on circuits optimzed for such use. Yes, the 20a breaker can pass up to 50-60 amps for perhaps the duration of the scene. Easily up to 40amps for a full 30 seconds! The problem exists in the branch cuircuit sizing, and instantaneous voltage drop. Up-size the wiring for subwoofer circuits. Rarely is there such an effective single step upgrade, with such a significant potential to eliminate a system chokepoint. YMMV on PS caps, the freq of the effect, the duration of the effect, etc, and these high speed PS configs need as much stiff voltage as possible.


Best of luck Stereodude, interesting findings.
post #44 of 91
Interesting to me. I recently posted in the SI subwoofer thread about all these people running 2 ohm loads. Doesn't seem like a very wise thing to do. I was told it doesn't matter and that if the amp is rated for it, it isn't a big deal. What I'm getting from this thread, was my initial thought that 2 ohms should be avoided. I'll be targeting a 4ohm load with mine.
post #45 of 91
Some subs are genuinely 2 ohm friendly, and as you start to pay more per watt for an amp, you start to see amplifiers capable of handling those tougher loads. If the though of it gives one a headache, most of the time finding a 4 ohm solution results in a marginal loss of maximum power. An amp that truly doubles in wattage as the resistance is halved (like a Krell class A amp) will likely not have an issue running 2 ohm loads, even with 'difficult' drivers . Inexpensive 'pro' amps are a bigger gamble, for the brief time I had an iNuke I found it was OK with three different types of drivers, not OK with two others I had. The bigger problem with the iNuke is that it fried after 5 shutdowns running one of those difficult subs - my Crown amps would never have done that. There are options if you want real 2 ohm stability... but you'll probably sacrifice light weight and efficiency for it, at the minimum. Otherwise it's just going to cost more per watt, more than just buying 4 ohm power in the cheap amps.
Quote:
Originally Posted by tuxedocivic View Post

Interesting to me. I recently posted in the SI subwoofer thread about all these people running 2 ohm loads. Doesn't seem like a very wise thing to do. I was told it doesn't matter and that if the amp is rated for it, it isn't a big deal. What I'm getting from this thread, was my initial thought that 2 ohms should be avoided. I'll be targeting a 4ohm load with mine.
post #46 of 91
But that's where my comment came from, that these amps everyone is using can "do it" but not well. Sure, some subs have a DCR of 1.9 and with the resonance peak around 30hz, most of the pass band is well above 2ohms. And a DIY'er can make that a consideration. But seems to me a lot of DIY'er are blindly slapping 2ohm loads on pro amps just cause they're rated for it. I'd rather play safe with a 4ohm load. Especially once we start to introduce eq. A little 3db boost here or there, is twice the output requirement.
post #47 of 91
I'd be the first to admit that wiring a cab up to 2 ohm is not ideal, but when you're working with (4) 4 ohm drivers you don't have a lot of options if you want to keep it down to one amp.

I'd imagine down the road I could very well get a second amp and bridge either, but until then I'll just look for a single that can handle a 2 ohm stereo load.

James
Edited by mastermaybe - 12/12/12 at 10:38am
post #48 of 91
My XTi-2002 has zero issues with the same drivers that choked the other amps at 2 ohms. I'm wired 2 ohm right now and was watching the new Bourne movie and I thought the amp clipped, but it was the bass making the glasses on the table rattle with such force, that's what I was hearing. I had to clear the room of any hard item on hard surface contact to continue watching. It was awesome. I think the XTi-4002 will totally rock. I'm taking my XTi-2002 to a GTG this weekend, possibly will see what happens when a pair of LMS-Ultras get hooked up to it.
Quote:
Originally Posted by mastermaybe View Post

I'd be the first to admit that wiring a cab up to 2 ohm is not ideal, but when you're working with (4) 4 ohm drivers you don't have a lot of options if you want to keep it down to one amp.
I'd imagine down the road I could very well get a second amp and bridge either, but until then I'll just look for a singlet that can handle a 2 ohm stereo load.
James
post #49 of 91
Don't know if my is close enough to be relevant, but I have an xls 602 running two pairs of Daytons in series at 8 ohms for each pair and the protection light goes off like a Xmas tree on WOTW
post #50 of 91
I've never had any of my amps cut out because of a signal input, including the XTi 4000, Itech 8000, EP4000, and LG 10kQ clone.
However I have been able to thermal the XTI and EP's, that is why I now use them for mid-bass's and PA woofers filtered at 30hz.
The clone and the itech are the only two amps I was unable to overheat thus far, at any frequency.
Note: I haven't taken the clone beyond 50% of power-supply output yet 4.2kW vs 8.4kW, so time will tell...

I doubt a XTi-2002 would max out a pair of LMS's IMO. Only the LG 14k, PS 10K and IT8k can do that effectively.
post #51 of 91
WOW reading this....I remember the same thing with my 2500 when I first hooked it up to I had forgotten about it completely. Mine was stereo 4ohm, When I re installed the subsonic 20hz 18db/octave filter I had zero problems. I have plenty of subsonic activity and my current subs need the filter( vented).
post #52 of 91
Lol, I'm fully expecting the LMS to max out the 2002, even one of them and the amp running bridged, unless the enclosure becomes too large to 'take advantage' of the LMS' motor strength etc. Just curious if the 2002 handles it well. If the iNuke 6000DSP couldn't max out the LMS, which evidently it could not... then the 2002 has no chance either because at 2 ohms the 2002's output is about identical to the iNuke 6000 at 4 ohms. My dream is an XTi-6002.
post #53 of 91
Quote:
Originally Posted by imagic View Post

My XTi-2002 has zero issues with the same drivers that choked the other amps at 2 ohms. I'm wired 2 ohm right now and was watching the new Bourne movie and I thought the amp clipped, but it was the bass making the glasses on the table rattle with such force, that's what I was hearing. I had to clear the room of any hard item on hard surface contact to continue watching. It was awesome. I think the XTi-4002 will totally rock. I'm taking my XTi-2002 to a GTG this weekend, possibly will see what happens when a pair of LMS-Ultras get hooked up to it.


Get on this everyone:

So I call the local pro audio guy who gave me a great deal on my XLS 1500's (for my L, C, R, W's, H's, S's, and R's) and 2500 to tell him that I'm thinking about upgrading from the 2500 to the xti for my subs.

I ask him if he has any 4002's in "b" or 'c" stock because I know it's well out of my range, new.

He checks and of course he has nothing but new. I tell him that I may just have to spring for the cheaper 2002, then.

Long story short: he says "you've bought a lot from me and I want to keep you around, just bring in the 2500 tomorrow and we'll make it work...merry christmas."

How the hell is THAT for customer service?!

James
post #54 of 91
How do the crown amps sound as LCR amps compared to what you have owned?
post #55 of 91
^ Absolutely indistinguishable from any other quality amp I've owned as far as I can tell...just prolly a handful more dbs.

When I looked at what I could get (6) Crown's for an 11 channel system, it quickly became a no brainer...build a decent cabinet, done.




James
post #56 of 91
Quote:
Originally Posted by imagic View Post

Lol, I'm fully expecting the LMS to max out the 2002, even one of them and the amp running bridged, unless the enclosure becomes too large to 'take advantage' of the LMS' motor strength etc. Just curious if the 2002 handles it well. If the iNuke 6000DSP couldn't max out the LMS, which evidently it could not... then the 2002 has no chance either because at 2 ohms the 2002's output is about identical to the iNuke 6000 at 4 ohms. My dream is an XTi-6002.

Yeah, it's always a game of "what runs out of gas, first".

I suppose as long as I have the output I want, it doesn't matter to me much. Prolly not even in this case with the 2500, really. Getting the 4002 will prolly just help me sleep a bit better. Which is goofy, btw.

James
post #57 of 91
Do they have built in EQ as well like the XTI amps?
post #58 of 91
^ Yep. F' it, let's just all upgrade to this:

http://www.crownaudio.com/usa/amplifiers/i-tech-4x3500hd.html


James
post #59 of 91
Quote:
Originally Posted by mastermaybe View Post

^ Yep. F' it, let's just all upgrade to this:
http://www.crownaudio.com/usa/amplifiers/i-tech-4x3500hd.html
James

Must..stop....too much...$$$

This place can get you in trouble so quickly.

Good news on the local dealer James. It's always nice when stuff works out that way. I did the same thing yesterday, bought some 2500s and then when back to swap for the CV5000s. Good luck with the trade
post #60 of 91
Just stumbled upon this thread.

I've got two XTi 2002 amps, each running an a7s-650 kit. I'm running about 4-6db hot and i've only hard clipped them twice.
Once during HTTYD when the large dragon smashed into the ground, the other during WOTW Pod scene.

No HPF, no limiter, very minimal cut in the EQ for room modes. Gains are full on. It's the only way to keep the out signal similar to the input signal in my setup off my 9.8.

I've thought about stepping up to the bigger XTi amps, but I got such a GOOD deal on the 2002s, that I don't think I will miss those few extra dBs.

Now if I only had 4 of those fancy new Dayton 18" drivers.....wait.....must....fight....the....urge to....upgrade.....wink.gif
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