Axiom Home Page Forums General Discussion Stereo Tight of Flabby Bass

Not sure if everyone caught this article in the last Axiom newsletter... I thought it was a very good read.

The whole article is good, but this is an interesting quote from Ian about how the lower-end of the Axiom lineup may actually produce more "tight" bass than the 600.

Sounds like you need an A1400, Mojo. Or maybe a MBM from Hsu.

I'm curious if anyone has tried the MBM? Seems like it would add a fair amount of colorization to the music. Maybe not. I guess that's why I'm asking. . .

More toys The MBM looks interesting, first time I've heard of it.

Alan really is very well spoken and that is a great read. It really got me thinking, so I decided to so a test. I went to my theater, and played a song that has nice "tight" bass. To limit my findings, I listened in stereo mode only (with my subs providing the bass). It sounded really good and "tight" and "full". It probably does because I calibrated my subs, and have a BFD to smooth the curves out.

Next, I turned the subs off. The "tightness" was still there, but the "fullness" was gone. I could still hear the quick attacks, but there was nothing behind it to fill it in.

Next, I set the mains to large, subs still off. The "tightness" was still there, and there was more "fullness", but not as much as with the subs.

Next, I set everything back to original, but brought the subs up 6db in the AVR. The resulting sound is would I would consider muddy. I loss the sense of "tightness".

Having said all of this, and after thinking about it for a bit, I drew an analogy to drawing a picture (people are always asking for terms to describe the sound, and in my mind anyway this a good representation). The M80s are drawing a nice sharp outline of a picture. The picture has a very nice sharp edge all around it. The problem is, that the color is weak, or not there at all. If you decide the paint the picture (to give it fullness), the sub can do this. If the sub is set too high, it colors the picture outside of the lines and covers up the sharpness and beauty of the original sharp drawing. If adjusted correctly, it colors the picture perfectly, and does not "go outside the lines".

Some posters have complained that the EP600 is not as tight as other subs. My speculation is that the sub may be set too high, or not calibrated correctly. This would result in the sub painting the picture a deep red, both inside and outside of the drawing. A weaker sub would color the picture short of the lines, in a nice warm pink. The resulting picture looks better than the black and white sketch, and certainly looks better than a deep red all over the place, but is still not as good as it could be.

I feel that the EP500/600 should be treated as a deep red paintbrush that must be properly applied (and not over-applied) to the overall picture to result in a masterpiece worth hanging in every home.

Thanks for the post, and thanks to Alan!

Dang, well said, Steve!

So the initial attack is a more complex part of the sound than what follows? That leaves me wondering if the additional sound is fundimentals or harmonics or... What? As always I would love to know the details.

A with life in general the more I learn, the less I seem to know...

You're making it too complex Fred, we're not doing Fourier Transforms here.

I'm sure that the sub would do just as well on the initial attack as the mains (if the sub was capable of the initial attack frequency, which it is not), but if it is turned up too high then the lower frequencies are amplified so much that they seem to overtake everything else. It just seems boomy.

I think the key is to adjust your sub to match (and not overcompensate) the mains. Thus, they approach the line that the mains drew, and fill in the colors (inside the line) deeper than the mains are capable of producing.

Think of it this way. The mains could fill in the picture with color, but as you get closer and closer to the center of the picture (the lower bass), the color becomes more and more pale. The subs have a more intense color, and are able to approach the center of the picture with more color than the mains. The key is to load-up just enough paint on the subs such that the color is as intense as it can be at the line, without crossing the line.

Well, I'm not trying to make it more complicated. I'm just trying to make sense of apparently disparate pieces of information.

Up until this thread, my understanding was that when one plucked blew or whacked a musical instrument one was generating a single wave which, depending on the instrument could generate sympathetic resonances that affected the nature of the sound.

I further understood that the initial attack was characterised by the amount of energy in it, and the rise time. The 'body' of the sound was then characterised by the sustain and decay of the wave plus any harmonics. Nowhere had I read that there was more than one sound wave generated by the initial pluck/blow/whack.

Then along comes this post suggesting (I think) that the inital attack happens in one frequency and the main 'body' of the sound in another, hence two separate speakers involved in defining/characterising the nature of the sound.

Draw me fuzzy and colour me confused...

Jason, the point Alan makes in his excellent article has been discussed here in the past and it's been pointed out that the lowest bass notes, which are played by a sub, are inherently slow and in no way can be described as "tight", regardless of the quality of the sub. Any tightness in the sound of a musical instrument playing a very low note, say in the 40-50Hz area, is due entirely to the upper harmonics which are played by the speakers, not the sub. As Alan again points out, a good demonstration of this is to listen to music containing a lot of low bass material through the sub alone, by disconnecting the speakers while keeping the settings the same as if all speakers were active. With a crossover in the 60-80Hz area(possibly steepened by also setting the sub's internal low pass filter to about the same frequency)what's heard certainly can't be described as "tight", "musical" etc.

OK, I think I'm starting to talk to myself on public boards. Not good.

From the article:

To me that says multiple fundimental waves with those in the attack being higer in the spectrum and (I'm guessing) with rapid decay.

Why, thank you for clearing that up for me Fred.

You are most welcome Fred.

No Fred, tell Fred that there's only one fundamental frequency in a musical note, but numerous harmonics, theoretically to infinity, but much weaker after the first few. It's the upper harmonics which make the attack of an instrument playing a note whose fundamental frequency is very low sound sharp and tight.

That Fred... Nice fellow, but very confusing.

Is this stuff written up in a nice neat package somewhere so I don't have to lurch about the internet picking up little bits here and there?

So if the fundimental is at 30hz, you would have harmonics at 90/120/150Hz that are very short in duration which characterize the initial attack?

No, wait, thats not it either. The harmonics will show the same rise in energy, including the initial attack, but its the re-enforcement of the initial attack in the harmonics that gives the sound its snap.

Do I win a prize or do I get sent to remedial classes?

Fourier analysis again... Just don't turn the sub up too high.

This is music. Math is inevitable and a confused Fred is the inevitable outcome...

Interesting discussion and an excellent analogy SRoode.

Fred,

I think you are pretty much on it here; but as you know it gets very complex fast. A piano, for instance, is a instrument that has strings that vibrate at a very precise frequency. It is not the strings you hear, however. When you strike Middle C, its the soundboard you hear, which is formed to generate a very complex (and pleasing) sound; its not just a 440Hz sin wave.

Remember that all sound is a wave, not just the fundamental.

Hi SRoode,

Thanks for your thoughtful comments--and everyone's posts-- and the excellent analogy. Just catching up to this thread, because I'be been writing newsletter pieces. . .

Regards,

Alan

Thanks Clay. I had forgotten that pianos have a sound board. I guess each type of instrument will produce its fundimental and resuting harmonics differently, but the physics and its effects remain the same.

Nuts - I just glanced at the title, read through the whole thing and then found out it had nothing to do with Jack's anatomy!

You're that interested in Jack's anatomy?

No - I was very frightened!

Fred, That the ONE that we can count on, its the bedrock of everything!