Bass management that we can all use? (1 Viewer)

[John Kotches]

Precision.
Infinitely variable dials are not known for being particularly precise. Where exactly are 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 etc, etc? Let's say you have a dial. 40 would be the bottom, 120 would be the top. Everything between is an estimate.
By using discrete values for crossover frequencies instead of a variable pot, you get easily repeatable results.
Regards,

 

[Chris PC]

OK. Do you think the 40 and 120 hz crossover settings are used very often?
Also, how hard and fast is the rule of using a crossover setting of approximately 2 x the -3 dB bass limit of your front speakers? If my (ported) speakers went down to 32 hz -3 dB anechoic, would it be possible to use a 60 hz crossover? I know it comes to tweaking and testing, but would it even be an option?

 

[John Kotches]

It's a general rule, to give you a starting point. From there you tweak by ear for your own tastes.
I'd go with 60 before I'd go with 80 for a speaker with a -3dB point of 32Hz.
I use 60 on my speakers, which are ported in front and ESL in back both with -3dB points at 35Hz. This gave me more satisfying results than 80Hz.
Regards,
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John Kotches
Contributing Writer
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[Chris PC]

Cool. Well, the bottom line is it works, right? I listen mostly to music, so thats the most important to me. I think I'd be happy with a little more flexibility than my receivers fixed crossover. I might be switching receivers due to other problems I'm having with my present SR 6200 receiver. I doesn't output sound. Its no surprise since I can't turn it on or connect anything to it. I'm being sarcastic. Its in for repair and its brand new, its been there for 3 weeks already. If I get it back and I'm not satisfied, I'm gonna ditch it for something else. The Marantz has, I believe a 100 hz crossover, which worked reasonabley well. I have been checking into the Onkyo TX-DS 797 as a replacement. It has similar power ratings, and lots of features I like. It happens to have an 80hz crossover, which is, at least, a step in the right direction from the Marantz.
Whatever I do, if I go with outboard amplification later to use with a receiver, kinda upgrading the power and keeping the receiver as a pre-pro, I guess I could give the ICBMa try as it would work well for my purposes.
[Edited last by Chris PC on November 12, 2001 at 07:23 PM]

 

[Chris PC]

Actually, since we are on the subject of bass, let me ask you this. With my old system, I had a pair of Boston Acoustics A 70 II sealed speakers. They had a 1 inch tweeter and an 8 inch mid/woofer. I paired them with a decent 50 watt per channel Technics integrated amp. It has worked well. I have recently replaced my Bostons with the PSB Image 6T's. I like the new speakers. Oddly enough, they sound very similar to the Bostons in that the sound is flat and uncoloured, clean and basically nice. The new speakers sound a little cleaner and will no doubt, play much louder.
Here is my question:
My Technics amp had a bass control with a center of 50 hz. I like lots of bass, as un-natural as it may be, so I often turned up the bass. Really, this never meant more than 3 to 5 dB of bass boost, and usually only at lower volumes, when bass seems less sensitive, at least to my ears. I like the bass controls use of 50 hz. It seems logical to me. Why do some audiophile grade receivers use 100 hz as a bass control center frequency. It really seems kind of strange. Wouldn't 50 hz be better? In my experience, a 50 hz bass control produces good results.

 

[John Kotches]

Because there's more "bass" information at 100Hz than 50Hz.
50Hz and below is only on the E String of a bass guitar (the longest one).
100Hz and above is on the D and G strings of a bass guitar (half the instrument).
The 100Hz center point pushes up more of the instruments normal range.
Read up on the "Fletcher Munson Loudness Curve" to understand why you like to turn up the bass control at lower volumes (hint: we're less sensitive to the frequencies).
Regards,
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John Kotches
Contributing Writer
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[BruceD]

John,
Let's say I use bass management in my pre-pro to re-direct the bass at the standard 80Hz (for DD, DTS, etc), I have the mains set to Large, select NO sub (so all bass is sent to the mains) and then insert an electronic xover (60Hz) on the mains with a sub. My mains are -3dB at 32Hz (no port, but passive radiator).
With this scenario, I seem to find very consistant and well integrated bass in both stereo and HT (after also inserting a parametric EQ on the sub to tame room mode peaks). My cost is slightly more than the ICBM (Marchand XM9-L xover $299, BFD EQ $169).
I believe this would also work with the other formats (DVD-A and SACD) if I decided to go that way.
BruceD

 

[John Kotches]

Bruce,
Yes, this would work in some respects, as long as you aren't losing LFE track info. However, your mains would need to be able to produce > 112dB (each) for you to maintain correct LFE levels (60-120Hz) as well as any center and surround activity from 80Hz-60Hz.
So if you want reference levels, this is likely not the way to go.
Regards,
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John Kotches
Contributing Writer
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[Edited last by John Kotches on November 13, 2001 at 02:34 PM]

 

[BruceD]

I wasn't aware I was loosing any .1 LFE. Do you know something I don't? LFE content is simply being routed to the mains with the SUB=NO command.
My Dynaudio Contour 2.8 towers don't seem to have any problem cranking out those SPL levels (according to my RS SPL meter C and slow).
BruceD
[Edited last by BruceD on November 13, 2001 at 04:24 PM]

 

[Chris PC]

I realize there is less music down at 50 hz, but it seems to me that if the slope of the bass control isn't too steep, a 50 hz bass control would make a larger impact on increasing the low bass content. I know what 100 hz sounds like. I am trying to increase the LOW bass, not the 100 hz area. Anyways, I guess it depends on the slope of the bass control and the program content. I notice that 2 to 4 dB of bass boost on my technics amp, which has a 50 hz bass control, seems to provide pleasant results with both speakers I have used on my system. Perhaps I might check to see what the bass control is on my Marantz SR 6200. If it is different, I'll play around to see how I like it.
I will definitely check out that bit about the loudness curve. I used the loudness control on my old amp and it worked well. I often had the loudness on and trimmed the bass back a dB or 2, just to prevent clipping the amp and/or blowing the speakers

I really like bass. I think there is probably almost a fave range of bass frequencies that I like. Maybe I can investigate which songs, tracks or other material i like and really try to figure out exactly what frequencies they are.
Thanks for the insight and info. I really appreciate the reference to music notes and frequencies. Thats what its all about.
[Edited last by Chris PC on November 13, 2001 at 06:42 PM]

 

[John Kotches]

Bruce,
The specifications for the LFE channel spec a reference SPL of 115dB (not counting any add on from speakers defined as small). The LFE channel goes out to 120Hz.
You are forcing LFE bass to go to your mains, because you have no subwoofer defined, and a 60Hz crossover engaged.
This means to correctly playback the LFE channel (at reference levels), you need at least 112dB maximum output from your mains from 60-120Hz (Crossover frequency to the end of the LFE channel).
I have not counted in any additive SPL from the Centers and Surrounds either, this could in theory push the requirements up to the (approximately) 120dB range from 80-60Hz.
This would require a combination of tremendous power, and
at least above average sensitivity.
If you aren't playing back at reference levels, this likely isn't an issue -- but you need to be cognizant of the limitations you are placing on your systems performance, and decide whether you are happy with the results.
You are the final arbiter of what's "right" in your system -- I'm giving you an opinion, with a smattering of information to help you make the decistion.
Regards,
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John Kotches
Contributing Writer
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[John Kotches]

Chris,
Yes, it is. I have a bizarre educational combination, which kind of ties this all together (music, frequencies, etc etc) from a hobby standpoint, but doesn't do me too much good on the professional front.
You like extra deep bass, which is fine. A 50Hz turnover on the bass control would certainly help you out.
Me, I like flat bass, that you aren't aware of until it sneaks up on you.
Regards,
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John Kotches
Contributing Writer
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