[biz97]

Hey all,

  I am debating upgrading my amplifier but need some opinions.  I am currently running 100 watt monoblocks and recently added a sub to my system.  Using some high pass filters from ACI (65hz), I am filtering out some of the lower bass.  After some initial tweaking (I'm sure I'll do a bit more after more listening) the results were very impressive.  Much clearer and more open sound.  Dynamics seem better too.  I am wondering if going from 100 to something like the Wyred4Sound 250 Watt per channel stereo amp would make another improvement since there would be even more amp overhead on tap for dynamic peaks.  I do not listen louder than ~85 db (avg listening session would be in the 60 to 70 db range), my speakers are rated at 86 db sensitivity, and  I sit ~7 feet away.   Thanks! 

[dweekie]

What are your current monoblocks?

[doug s.]

i would upgrade to an active x-over first.  this will improve the sound of your speakers more than an amp will.  here's a relatively inexpensive way to try:
http://www.audiogon.com/cgi-bin/cls.pl?homesubw&1231009552&/NHT-X-2-Subwoofer-crossover
also, add a second sub; the soundstaging will improve, and your room will be more evenly loaded. 

with your listening habits, you could halve your amp's power and still be ok, no reason to double it.     especially if you usa active x-over/subwoofers...  if you actually want to "upgrade" your amp (which is?), not yust increase the power, consider tubes.

doug s.

[biz97]

Hey guys.  Right now I am using CIA D100's with the PLC-1 passive.  Would using this crossover prove problematic with a passive line controller?  I had definitely thought of adding a second sub after doing using that handy tool on the Crown Audio web site to calculate ~ how much power I was using for my needs.   

Definitely want to give another  to Rythmik subs.   I will look into both another sub and this active crossover too.  Thanks doug s. and dweekie!

[doug s.]

w/an active x-over, you yust run the outs from your preamp - active or passive - to the x-over, then from the x-over, the hi-pass goes to the mains, the low pass goes to the subs...  another upgrade - imo - would be to go w/an active (tubed, preferably), preamp...

doug s.

(btw, the cia gear is top-notch, i really don't think changing the amps to similar topology amps w/twice the power, will offer you a meaningful improvement.)

[biz97]

Doug S,

  Thanks again.  I was hoping that would be the case.  I do love the amps and I think like you said adding the additional sub is a better bang for the buck.  One last question,  I noticed on the NHT that the hi-pass points I'd be looking at would either be 80hz or 50hz.  I think 50hz might be a bit low but 80 a bit high.  My speakers are rated ~35hz I believe.  I have heard that adding that second sub would allow for a more seamless blend at higher crossovers though so maybe the 80 would be ok?

[doug s.]

biz97, i did some research on this nht unit; you can check it here:

http://nhthifi.com/current/manuals/current/X2_Manual.pdf

based on the fact that it offers only 12db/octave x-over slopes, i have to back off a bit on my recommendation - for sub x-over, i would recommend at least 24db/octave.  but, i still recommend you explore the outboard x-over option.  personally, for standard (non-digital dsp) type x-overs, i recommend marchand.  you can get them in different configurations, and different plug-in x-over frequency  modules are inexpensive.  the units themselves are not that cheap, tho. 

and yes, if you run stereo subs, 80hz would be a fine x-over point for most situations.  but, that's assuming 24db/octave slope.  if you run only one sub, 80hz would still be ok, but you would then wanna have the sub directly centered between your speakers.

one other thing - if you are running a powered sub w/built-in x-over, you would want its x-over set as high as possible, and preferably double that of the outboard active x-over...

doug s.

[biz97]

Thanks for the heads up!  I did have one other question about setting the volume for the subs. After I have found a crossover that sounds good what is the best way to set the levels for the subs?  Coming from the home theater world  I would just use the test tone  and my RS SPL meter to get it in the ball park and tweak from there by:

Running the test tone to the main speaker and get it to 80 db
Runing the test tone to sub 1 and get it to 77 db (corrected)
Turn on the second sub and work the levels to get both subs to output at 80 db (corrected)
I'm putting corrected due to the fact that the SPL meter isn't as accurate for lower frequencies.

If I am trying to mimmic this approach can anyone recommend some test files that are ok to use?  If so, which should I play on the mains and which should I play on the subs?  Thanks!

[biz97]

Bump 

[doug s.]

i have used pink noise generator and spectrum analyzer for starting point to set first adjustment starting point; what you propose seems a similar solution; sounds good to me.  of course, final tweaking by ear is ok - you want it to sound the way you like it.   

doug s.