High order crossovers

Do or can high order crossovers rob a speaker system of more dynamics?
@audiokinesis, "@trelja, can you tell me what the actual mechanisms are by which crossover parts count and/or conventional crossover topologies constrain dynamics? There may be effects I’m unaware of that are worth taking into account, even if they aren’t necessarily the primary cause of compression. You may be correct that a steep crossover slope constrains dynamics, but can you tell me why? The "why’s" interest me a great deal."

Thank you, Duke. The "why’s" interest me a great deal, as well! That’s where the fun and advancement come from. I believe the issue under consideration is actually quite a simple thing. To make the point let’s go back to Electronics 101.

Resistors represent a fundamental component in the toolbox. Resistors reduce voltage, reduce gain, reduce dynamics. We use that to our advantage. When a mother, wife, roommate, dorm captain, guy sitting next to us on the bus, police officer, etc. tell us to turn the sound down, we make things quieter by adding more resistance to the respective audio signal, and (hopefully) restore the peace. We reduced the volume / dynamics from an objectionable level to something others can accept. That’s obviously what the volume control on a preamplifier does. We also use resistance to reduce the voltage through the succeeding stages of our power supplies to suit the needs and limitations of the downstream components. Likewise, as tweeters traditionally play louder than woofers, we use resistance to lower the tweeter’s voltage which translates to volume and dynamics to some level closer to the woofer in order to balance the sound between the two drivers out, and produce an overall better result. Resistors, no matter how small cannot and do not add voltage or volume or dynamics, and they cannot and do not leave the voltage or volume or dynamics unchanged. Resistors, no matter how small, reduce the voltage, reduce volume, reduce dynamics. Add resistors, no matter how small, to loudspeaker crossovers, and we reduce volume / dynamics of that loudspeaker.

Inductors are another fundamental electronic component, and typically a part of the crossovers discussed in this thread. They block part of the musical signal from getting to a driver, intentionally so, as we cross over from one driver to another. Every piece of wire, regardless of its elemental composition or length, has resistance. Increase the length of wire and we increase its resistance. Longer wires have measurable and meaningful levels of resistance. Inductors are made from a long (can be 50’, 100’, or even 300’) piece of wire, coiled upon itself. In fact, one specification of an inductor will be its resistance. In other words, on some level since an inductor consists of a long piece of wire, an inductor is a resistor. Again, resistors reduce dynamics. Use an inductor, and you’ve increased resistance and reduced dynamics. Moving from the typical 16 or 18AWG to an 8 or 12AWG often brings the comment of the obvious increase in dynamics and slam. Why? Because its resistance has decreased. Not to the zero not having the inductor at all would represent, but it shows adding components adds resistance which reduces volume and dynamics, and vice versa.

Capacitors are another fundamental electronic component, and like inductors, usually a part of crossovers discussed in this thread, and also block part of the musical signal from getting to a driver, intentionally so, as we cross over from one driver to another. Capacitors also have resistance, commonly noted as ESR (equivalent series resistance). No need to repeat the same statements as inductors, other than to say add a capacitor and we’ve added resistance which reduces volume and dynamics.

The number and position of inductors and capacitors in the crossover leg in the typical parallel network determines its slope. Second order crossovers have an additional inductor and capacitor from a first order crossover. Third order crossovers have another inductor and capacitor from a second order crossover, and so on. Like for like, fourth order crossovers have more inductors and capacitors than third order crossovers, which have more inductors and capacitors than second order crossovers, which have more inductors and capacitors than first order crossovers. Beyond that, there are compensation networks, made up of additional resistors, inductors, and capacitors a loudspeaker designer may add to the basic layout to suit their design goals. These will also to varying degrees, add resistance to the overall crossover. Additional components work in an additive, in terms of resistance, manner. As previously stated multiple times, adding resistance reduces volume and reduces dynamics.

Again, crossover slope absolutely rob dynamics, substantially so

@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?


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

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!


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.