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High order crossovers

Do or can high order crossovers rob a speaker system of more dynamics?
koestner
audiokinesis
2,747 posts
 

@trelja , thank you for taking the time to explain your position.

My understanding is that series resistance decreases the voltage going to the driver (perhaps more precisely, it decreases the voltage drop across the driver).  So it decreases SPL accordingly.  I think we are in agreement there.

But dynamic contrast is not the same thing as sound pressure level.    Dynamic contrast is about CHANGES in sound pressure level. 

So dynamic contrast is about voltage ratios.  A voltage ratio of 10:1 is a 100 fold increase in wattage, and therefore a 20 dB increase in SPL (ignoring compression effects). 

And adding series resistance has no effect on voltage ratios. 

Say we have an 8 ohm driver, and we increase the voltage going into the speaker from 1 volt to 10 volts.   The voltage ration is 10:1, and assuming no compression effects, the SPL that the driver is producing goes up by 20 dB.

Suppose we put a 2 ohm resistor inside the box in series with the driver, and we send 1 volt into the speaker.  Now the driver sees .8 volts.  If we increase the input to 10 volts, the driver sees 8 volts.  The voltage ratio is exactly the same, 10:1, so assuming no compression effects, the SPL that the driver is producing goes up by 20 dB.

So it is not obvious to me that series resistance reduces the voltage ratios that a driver sees, and therefore I do not see how it would reduce the dynamic contrast.  The volume level being reduced is not the same thing as the dynamic contrast being reduced.

Am I missing something?

Duke

royj's avatar
royj
151 posts
 
Good answers, Duke. Thanks for stepping into the batter’s box!

I would add there are many crossover parts, mostly capacitors, that cannot pass small signals and/or very large ones. When a crossover can be made simple, this can be easy to hear unless the drivers are lame, which is another big problem. Duke, you allude to that in your comments about hearing those bass-guitar drivers compress the input signal.

When a completed speaker cannot pass small signals, for whatever reason, this means it does not pass low-level details. It produces what I call an ’On-Off’ sound, meaning the music has a ’Jump’ to it but lacks any Grace or Swing, two signals that are 'Small Changes'. Many audiophiles and designers are not wired to hear those, but let’s not go there.

When the delicate signals that an Atmasphere S-30 can pass are blocked by such a speaker, the music will be boring so that amp ’must not work for these speakers’. True-- the preferred amp, or cables, DAC, or preamp fills in those small-sound gaps with its less distinct, more smeared sound. Which is what one usually gets when an amp employs more and more output devices, for example.

I have heard smeared-sounding speaker wires be made more ’analytical’, more distinct sounding by using the same company’s interconnects. Used with all sorts of other speaker wires, those interconnects were clearly ’Off/On’ sounding. These were the only wires in this reference system, fyi. I have heard the same from some amps paired with their matching preamps.

Keep on listening!Roy
audiokinesis
2,747 posts
 

Thank you Roy!! If you see any mistakes in my posts, PLEASE correct me!

Roy makes the best-imaging speakers I know of. If I hadn’t crossed over to the Dark Side and become a manufacturer, I’d still be a dealer for him.

Anyway just to clarify a bit, imo my bass cabs actually have pretty good woofers - my point was that thermal compression can be fairly audible when it sets in.

The bass guitar world is less prejudiced against little guys than the high-end audio world.  If you’re REALLY bored, one of my bass cabs was just reviewed by Bass Gear Magazine: http://https//www.bassgearmag.com/audiokinesis-changeling-c112t-bass-cab-real-world-science-fiction/

They seemed to think it didn’t suck too bad.

Anyway I hear what you’re saying about capacitors. I’ve not paid much attention to capacitor quality in the past, kinda just threw some money at the issue and hoped for the best. Recently I’ve gotten some valuable advice from someone who knows a lot more about capacitors than I do, so I changed a few things and yup it makes a difference.

I’m going to start listening for the "On/Off" phenomenon you describe. Totally agree with you about the importance of low-level details. THANK YOU for the heads-up!

Duke

johnk's avatar
johnk
1,975 posts
 
I think one needs to look at loudspeakers as the sum of their design and parts. Focusing on one aspect like networks not really useful for if wanting greater dynamics in loudspeakers one looks for a more dynamic design and it could have a good num of network types while still achieving that performance goal. Personally I prefer simple networks and  physical alignments but the reason I prefer simple if possible is the increase in detail and soul not dynamic range. When I design if requiring too complicated a network I redesign I look at it like a design flaw .        But with all things YMMV.
erik_squires
16,235 posts
 
@trelja


" Resistors represent a fundamental component in the toolbox. Resistors reduce voltage, reduce gain,


Yes, right right ..

... reduce dynamics"


Woah, no, they don’t. They could only do this if they were non-linear. Resistors are the most linear parts in the entire audio chain, except wire. If you are going this way, you might as well get rid of every volume control and only listen at full output. Hahaha. :)

I think you are confusing output level (dB SPL) with the ability to present music without compression. The latter is how I define dynamics.

High sensitivity drivers like in horns have the advantage in dynamics not because they are loud, but because they suffer much less from thermal compression. That is, the coils and motors heat up less and can handle more heat.

While resistors and other crossover components and even drivers may suffer from this, it is up to the designer to keep all of them well within spec. None of this makes the argument that high order (4th) is less dynamic than low-order (1st, 2nd).

This is why I use 5W resistors when 2W are called for. :) 

Best,

E
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