Hooking up sub to Pro Amp Crown XLS 2500, no sub out?

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Hi, I just got a pair of LSI9, I have some questions on these that I'll ask later. But right now I have them connected to my Crown XLS 2500. Can I add a subwoofer to this? I've looked and it seems possible I'm just a little inexperienced. Right now I have a Polk PSW10, with speaker lineouts.

Also, how should I set the gain on the crown? I found one post, suggesting to max the preamp and then set the gain accordingly. Then move down the preamp as needed. Sound right? Any help is much appreciated.

Liking the LSI's right now but they've me realized my RTIA3's don't get the love they deserve. The LSI9's are better in every respect, but if you can handle the brightness and have a sub you're not missing much with the RTI's.

Also, I guess I'll just ask this now. But should the vocals and treble be drastically forward with the LSI9's when compared to the RTIa3's? I haven't listened the rti's in a while so its kind of a distant memory but it seems so. It has me wondering if the guy I bought them from on CL was up to something. He was super nice guy but I don't know, it's probably me being neurotic, but he was just selling just the fronts, had the LSIC ect. that he wasn't selling. It was probably just CL awkwardness but he didn't sound super trustworthy when he said he was just selling for bills, yet kept the center, $300 cables, amp ect. Also, it was late so he didn't want to turn it up loud, really at all, like 2-3 on the dial. He put on jazz for a second and then I asked for rap to hear the bass but he kept talking almost as if he was keeping me from listening. Bass sounds somewhat alright, definitely subdued and not super tight a little flabby. I hear the midbass hump and there's congestion, I'm hoping most of this is corrected when I get stands. However, the vocals/treble are noticeably forward and sometimes just a little sibilant, I kind of like it but I mean sometimes everything but the voice is very subdued. I'm wondering if he burnt up the crossover? I doubt it but I figured I'd ask. I might be also looking for the silibance because I read that's what happens when it gets burnt. The more I listen the more I get over it. He did have them listed up on eBay as well so I doubt he would mess around on there, albeit it was for pick up only.

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  • [Deleted User]
    [Deleted User] Posts: 7,658
    edited August 2015
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    Hello,
    One subwoofer connection method would be to use a pair of "Y" cables to provide another right and left preamp signal to the corresponding right and left line level inputs on the subwoofer. You'll need two "Y" cables that have a male plug on the base and two female connectors on the two "branches". Use one right and left female connections to the Crown and the other to the Polk.
    As to the LSi9s, on the rear of the cabinet there are two pairs of binding posts with jumper plates joining the upper and lower. One-at-a-time take each speaker, loosen the binding posts so you can disconnect the jumper plates. Then, at a very low volume, try connecting the amplifier to the upper set of binding posts. You should just hear the tweeter being played, there should be no distortion, just high frequency clean sound at a low to moderate level. Now do the same thing with the lower binding posts, again at lower volume there should be no distortion with the two mid-bass drivers playing.
    Do this with the other speaker.
    Regards, Ken
  • Cbale
    Cbale Posts: 8
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    Ok thanks, when I get the time today I'll give that a try. So with the sub split the signal with a y cable and then I'm going to set both the amp and sub's crossover to 80hz.
  • [Deleted User]
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    It's probably a good starting point, some prefer higher, others lower. It will depend upon the steepness of the high and low pass filters used. The goal is to get a seamless blend between the speaker and the woofer. Listen to well recorded music and make small adjustments to get things correct.
  • Cbale
    Cbale Posts: 8
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    I don't have much experience but I tried what you suggested with the different terminals and compared it to my rtia3's. The rti's sounded a little clearer on both terminals. The LSI were not too far off, there was no noticeable distortion. However, it looks like the screws were stripped a bit on both end backside and on the front.Unless they come from the factory that way, at the very least someone looked inside the speaker. I might text the guy and hope that he's straight up.

    I was planning on using it stock but with all considering I might just get it modded and maybe they'd be able to tell. Is vrx3, the only guy doing it? Is there a cheaper alternative?
  • Nightfall
    Nightfall Posts: 10,073
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    No, @westmassguy also does crossover refreshes.
    afterburnt wrote: »
    They didn't speak a word of English, they were from South Carolina.

    Village Idiot of Club Polk
  • MetropolisLake
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    Cbale wrote: »
    Hi, I just got a pair of LSI9, I have some questions on these that I'll ask later. But right now I have them connected to my Crown XLS 2500. Can I add a subwoofer to this?

    Yes, of course you can. This is one of the easiest amps to add DIY subs to. Skip the petty stuff and go straight to 18's, like UltiMax's or Stereo Integrity. I think this amp is like the new 2502's like I have and if so you can set it to where it accepts 0.7V natively (pro stuff usually operates on 1.4V) plus it should accept RCA cables natively. I'm running two 18's on the updated version of this same amp.

    Cbale wrote: »
    Also, how should I set the gain on the crown?

    Mine is a little over halfway. If you like them hot, it's usually better to boost it in your receiver more if possible, otherwise the noise floor rises and you can hear hissing in your subs.


    Cbale wrote: »
    I found one post, suggesting to max the preamp and then set the gain accordingly. Then move down the preamp as needed. Sound right? Any help is much appreciated.

    If you have Audessey I would run it and set the gain accordingly to be flat, then use the preamp to boost it. Most people like running the subs like 6 db hot. Don't do this part on the amp.
  • Conrad Luxman
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    Do not run the pre-amp flat out and then adjust the Crown, that's very bad advice. Find the sweet-spot on the pre-amp, usually around 10-1 o'clock on the volume knob, then bring in the Crown to where you want the volume. I've been using the Crowns for my two main home rigs for several years with great results. They will run at 2ohms all day with out the fan even coming on, so piggy-backing multiple speakers is a breeze.
  • MetropolisLake
    MetropolisLake Posts: 128
    edited October 2015
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    Do not run the pre-amp flat out and then adjust the Crown, that's very bad advice. Find the sweet-spot on the pre-amp, usually around 10-1 o'clock on the volume knob, then bring in the Crown to where you want the volume.

    Well first of all I read it wrong and thought the guy wanted to use his Crown for subs, which is becoming a pretty popular thing to do so I jumped the gun.

    However, if somebody did do this, it's not exactly bad advice, as you don't have much of a choice. On many popular AVR's and preamps, you basically have a -12 to +12 sliding scale on the subwoofer output. Typically you will set this to zero then run Audessey, which will ask you to adjust the gain on the amp so that it is hitting as close to 75 db as possible. It will then adjust the output levels and frequency response. At that point you know it is correct, and can trim the subwoofer level inside of the preamp however you see fit, without touching the gain, such as running them 6 db hot.
  • cooley53
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    Had the pleasure of hearing the Crown xls 2500 thru some a/d/s 810's. Pretty nice set-up. Looking at a 1500 or 2000 for myself. Good prices and reviews online.
  • ConradLuxman
    ConradLuxman Posts: 2
    edited October 2015
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    Conrad Luxman @ MetropolisLake:

    I'm strictly stereo and tube preamp so you have a very different setup. In principle, you never run a pre amp flat out and then bring up the amp. Maximum distortion being amplified.

    Using a Crown XLS amp just for subs is like using your Corvette to haul groceries. The XLS will outperform any receiver, by far. Try it.
  • ConradLuxman
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    cooley53 wrote: »
    Had the pleasure of hearing the Crown xls 2500 thru some a/d/s 810's. Pretty nice set-up. Looking at a 1500 or 2000 for myself. Good prices and reviews online.

    I'll bet that sounded good. I have found that it takes a little getting used to the XLS "sound", which is "no sound". They are so amazingly clean, neutral, and powerful that they will amplify all, the good, the bad, and the ugly. If you have stellar source material and good pre-amplification it will sound fantastic. If you play poor recordings through poor pre-amplification you will hear all that awfulness very well. There is no coloration and they are very fast. Music sounds very different through amplification with very fast slew rates and instant power capabilities. It let's one hear the recording art as well as the musical content, they put out what you put in. Less efficient speakers benefit greatly from these characteristics.
    Here is a pic of my rig, the XLS is running 2 sets of Infinity Crescendo series speakers in a D'Appolito set up.e8txja354gmj.jpg
    i51r536sfw96.jpg
  • Conrad Luxman
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    I have moved the above speakers to my computer room and have replaced them with their big brothers in the Infinity Crescendo line. Still in D'Appolito set up but getting into linear array territory with nine drivers in line per side. Still being run by a single Crown XLS-1500 putting out 575WPC which is more than enough to run these 8ohm enclosures in parallel. The XLS rarely blinks the second light and the fan is yet to come on. The best sound I have ever had in my home in the last 40 years.x5o3ekah60v9.jpg
  • Conrad Luxman
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    My apologies to the original poster, I'm an old timer new to blogging and my son told me this is "hijacking" a blog. I did not mean to do that, I thought it was a general discussion on the merits of the Crown XLS. Live and learn. :o
  • MetropolisLake
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    Using a Crown XLS amp just for subs is like using your Corvette to haul groceries.

    Ha. Clearly you're not into home theater subs much. If anything the XLS is kind of lacking for subwoofer use, especially the new DriveCore 2 like the 2502. There is a 6 db per octave slope below 20 hz where it wimps out. Play with it much on subsonic material with constant output and the limiters will kick in and start clacking way before your subs wimp out. Oh, and they took out the ability to override the limiters like on the original XLS's. Thanks Crown. So right when you need power the most it turns into weak sauce and throws on the brakes. Even the Behringer iNukes outperform them, even one iNuke 3000 can spank the largest XLS, especially considering it even has a built in DSP. It's more like putting a 4 cylinder in an F-250. It sounds pretty nice on subs and can get powerful enough for lots of applications, but, don't kid yourself.
  • Conrad Luxman
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    Ha. Clearly you're not into home theater subs much.


    Yes, you're right, I'm strictly stereo and listen to 90% music with the occasional bluray. I cannot imagine a living room situation where just one XLS 1500 would be insufficient for bass or volume. 525WPC @ 4ohm is enormous power for a living room. At the highest levels I care to listen to the second lite on the Crown amp does not come on yet, the fan has never come on. The 6 x 10" woofers in the Infinity setup are capable of all the bass I would ever want. I guess that reproducing movie explosions and rumbles could eat up lots of power but HiFi was always my cup of tea.
  • MetropolisLake
    MetropolisLake Posts: 128
    edited January 2016
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    Yes, you're right, I'm strictly stereo and listen to 90% music with the occasional bluray. I cannot imagine a living room situation where just one XLS 1500 would be insufficient for bass or volume. 525WPC @ 4ohm is enormous power for a living room. At the highest levels I care to listen to the second lite on the Crown amp does not come on yet, the fan has never come on. The 6 x 10" woofers in the Infinity setup are capable of all the bass I would ever want. I guess that reproducing movie explosions and rumbles could eat up lots of power but HiFi was always my cup of tea.

    Put it this way, since I wrote that, I just blew up my Crown 2502 that has 2400 watts into 2 ohm stereo. It couldn't take it, started acting all weird where any bass hit has this weird high pitched concussive sound as if the internal capacitors are shot or power supply is toast. I shipped it back to Crown a few days ago, luckily it is still under warranty. So much for the Corvette analogy. They're just not that great for serious home theater subs.