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Crown XLI1500 a modern day staple?


jwc

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On 5/7/2017 at 11:56 AM, John Warren said:

Need a sub however to handle the low stuff. 

It took the evolution of Home Theater Technology to get me to realize that a Klipschorn needed a subwoofer. I never realized that pipe organs could go down to 16 Hz., along with some extreme sub bass things in movies, until digital media became available, where vinyl failed to deliver. Having tried all the Danley TH HT worthy subwoofers, I'm convinced that going from 40 down to below 20 Hz. is a VERY expensive proposition, relative to the rest of the horn systems.

 

Having "botttomless" bass, so to speak, allowed me to discover all kinds of loose things in my house when doing pure sine wave testing a reasonable output levels. BUT having said that, it is quite a revelation to have this performance added to a system.  This is true even when it's rarely called upon to do it's thing for music, but mostly by Blue Ray movies with explosions. So having amplification specifically for those super low frequencies is a necessity and we all seek the best bang for the buck.

 

I personally prefer FANLESS Crown K2's available on the used market for about $500. They have a built-in 8 Hz. high pass filter. They cost about $1,600 New about 12 years ago and represent a very rugged, high quality build that is ideal for subwoofing in style. At between 800 to 1,200 watts per channel in the 4-2 ohm range with 12 AWG wiring, they never fail, or fail to please, while potentially pissing off the neighbors!!

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On 6/4/2017 at 3:06 PM, John Warren said:

Note the response is +6dB in the passband because the model considers balanced inputs.  And yes, the output at that the Speakons is in-phase with the input!

Nice work. As a veteran PCB designer, I see your layout is not that critical. Are the op amps a dual variety?

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On 6/29/2017 at 4:31 PM, John Warren said:

It would take a wheel-barrow of parts to make this in a passive, no thank you.  

This why I personally believe in an active/passive hybrid approach to Xovers. Being that our hearing sensitivity is much less in the bass area, we can also mess with PEQ's to flatten things out in a real room. It's easier to mess with film capacitor values from 1-50 uF in the midrange and tweeter passive sections. I my case I was using a single cap for highpass and relying on Audyssey to flatten things out in the room. The 3rd order high pass characteristic of horns, usually accompanied with a first order rolloff at the higher end, makes this ideal. Adding a single cap for the high pass on the bottom of a mid horn gave me a 4th order rollof. The huge K1133 drivers never saw more than 50 Milliwatts in normal operation, so operating the driver Bandwitdh to it's almost full natural state coupled with the horn bandpass characteristic yielded some very smooth and detailed midrange and tweeter sounds, but it took several trial and error sessions with different tweeters to get that right.

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These days, however, I'm about to embark on 24/96 Khz. Xilica and Yamaha digital Xover controls that can simply be dialed in ahead of power amps. I can even listen to test music while tweaking the PEQ's, Xover points, and slopes. Using instruments and ears both, IMHO, yields the best sonic experience in any given space. Something the Klipsch engineers do every day.

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3 hours ago, ClaudeJ1 said:

It took the evolution of Home Theater Technology to get me to realize that a Klipschorn needed a subwoofer. I never realized that pipe organs could go down to 16 Hz., along with some extreme sub bass things in movies, 

 

I agree but must put the Klipschorn bass unit on a bandpass, all goodness then.

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On 8/9/2017 at 3:47 PM, John Warren said:

Yes.  For subwoofer integration, I'd recommend the bass horn be bandpass filtered.

 

 

Yes. It's not just for bass reflex and turntable subsonic anymore. A K-33 woofer produces WAY les IM distortion if the part below the horn's cutoff is filtered out and replace by a subwoofer "air pump."

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  • 2 weeks later...

Doing a bandpass using a passive means large capacitances so electrolytics are a way to keep the cost reasonable. 

 

Some time back I put an electrical equivalent model together of the Klipschorn bass unit using the Beranek approach shown in Acoustics (http://www.northreadingeng.com/Klipschorn_model/basshorn_model.htm ).

 

That model is useful as a simulated load for passive filter designs and it provides a way to predict a Klipschorn bass horn response for various filters. 

 

In the first plot the pink curve is the model output response (electrical equivalent) of the Klipschorn bass unit with no filter (raw).  The peak in radiation resistance is ~100Hz and below that the horn output drops. The output below 70Hz (or so) is not due to horn loading but due to the woofer working is a sealed enclosure and firing into a folded labyrinth.  That's shown in the dash line in the second plot, it's the seal woofer response.  This provides the "salami whacking the sofa" sound characteristic of the Klipschorn.   Combined is the measured Klipschorn response.  It's the sealed woofer response that needs to go.

 

Using the model as a simulated load, the blue plot is the model response with the AK4 network, the green is the AK3 and the light blue the AA.  The AK4 is the notch filtered net with the dipsy-doo in the range above 150Hz, the idea to attenuate the peaks that occur over that range. 

 

The red plot is the model with a passive band-pass filter, it will attenuate the seal woofer response.   

 

filter_responses.jpg

filter_responses_2.jpg

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Getting a bit off topic.

 

Simulated impedance magnitudes from the model show why the AK-4 was revised to the AK-5.  The minimum is getting a bit too low. The AK-5 adds a little extra resistance to bring the level up to something closer to 4 Ohms over the range where the notch is dissipating.

 

Z-magnitude.jpg

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  • 5 weeks later...

Hi John, amazing things i see here, for a newbie like me ... I have a Crown XLi1500 and I want to make it a better home hifi amp for my tower speakers Paradigm Monitor 11 v.7.  I like the drums/bass to be fast, articulate, punchy ... I hate low, slow bass woowing in my ears ... and seems XLi1500 might be a nice budget solution :)

 

In a previous post you said: "If there's one place where this amplifier can be improved is the power supply"

 

Please tell me what do you recommend regarding this subject?  the filtering caps? some 4 x 12000uf/63V Nichicon will be an improvement?

(replacing those 4 x 10000uf/63V RM)

 

Thank you for your time! 

 

P.S. Already noted the 2 coupling capacitors to be replaced with Nichicon Muse 10uf/25V ... are to be more of those needed to be replaced?

 

 

 

 

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  • 2 years later...
On 1/26/2020 at 3:31 PM, ZoSoIV said:

Hi guys I know this is an older thread but what the consensus on these Crown XLI 1500 amps ? I was considering this amp for a pair of Klipsch Cornwall II , will the amp handle the load , warm SQ etc. ? Had a Halfer 500 I should of kept it 

FYI: XLi1500 is apparently on sale at Amazon: $199. 

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8 hours ago, Dave A said:

Those xli's are WAY more than you will ever need to push Cornwalls. 330 watts at 8 ohms per channel is three times + the rated intput of Cornwalls at 100 watts maximum continuous input.

Yeah @102 dB @ 1 watt you don’t need a huge amp I understand, SQ wise , warmth etc think I’m going to be good with this amp ? 

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8 hours ago, ZoSoIV said:

Yeah @102 dB @ 1 watt you don’t need a huge amp I understand, SQ wise , warmth etc think I’m going to be good with this amp ? 

I have been happy with mine. Running pro gear like KPT-456's and a set of MMCM 1900's sounded really good with an xli800. EQ can change how you flavor your music. Now with Bi-amping and a xilica I figure I can duplicate most anything within reason to get a tube like sound to raw heavy metal or cellos or pipe organs.

 

  Why don't you try to find someone close by who will let you borrow an amp and see what you really like? Bang for the buck I like the Crowns. Got rid of an Integra 50.2 amp that was supposed to do it all for the Crown and no regrets.

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My 35 year old Crown Power Line One finally gave up the ghost, and I replaced it with an XLi1500.

 

While a couple of the XLi specs (THD and noise level) aren't quite as good as the Power Line, I don't notice any differences in the performance.

 

My two intial fears with the XLi (ambient hiss and fan noise) are a non-issue; neither is audible over 1 foot away.

 

Having the additional headroom (50 watts up to 330 watts) is nice too. I rarely crank it up to extreme levels, but that is certainly an option now.

 

All in all, $199 for this amp is a steal.

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FWIW, maybe the best sounding amp I've ran on my Belle clones is a highly modified and upgraded Carver M-1.0t MkII Opt 002 (long name) that went from a stock 200 wpc to about 450 wpc.  Overkill for something that's 104db @ 1-watt?  Sure it is but it is dead quite with the Carver C-1 preamp (BillD mods) that is in front of it.  Together, the combo are quite special.  That Carver amp sounds better than any tube amp I've ran on the clones.  Eventually, it will be the 80 wpc Onkyo Reference M-5000R running them but, for now, this works.

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