that and you are using 6.5" midrange speakers for midbass.

 

What should I be using? 7-8"?

 

at least... but as mentioned in other threads, dedicated midbass drivers usually only get to about 1khz before choking. some not even that, or have nasty break up just above that which will show up if crossed over too high.

 

the 7" midbasses i have will roll off naturally at 4khz. may be an option

 

Unfortunately, this "natural rolloff" is not something you want to hear. It's actually due to severe breakup modes, and contains loads of non-linear distortion. Any crossover should begin a minimum of an octave below the driver's breakup modes. That pushes that 4k rolloff down to at least 2k. This is why large drivers generally make lousy midranges.

 

well not all have ugly break up modes... my peerless 8s roll of smooth. But I know the Peerless SLS's are frightening just a little over their comfort range.

 

Whether the rolloff is smooth or not is not the point. It actually doesn't matter. The F2-5 increase dramatically within an octave of the rolloff "knee" (even in what appears to be a smooth rolloff) and these have to be eliminated by keeping the XO point low enough to avoid activating them. There's far more to a driver's character than it's response curve.

At this moment, I'm working on a Seas 2-way setup that has some of these considerations. I'll try to get some examples together when I can.

 

There are still some things that are not avoidable in audio, and IMO frequency range is the most important factor when it comes to midbass performance. That being said the single biggest difference I have seen in midbass response in any audio system I have had is keeping the midbass drivers's frequency range as small as possible. I spent many hours playing with my Focal polykevlar 7" midbass drivers from 50hz up to 3.5khz in every possible combination. The best midbass I ever got from them was to play them from 63hz through 250hz. Way more impact, much cleaner and more accurate. Take the same driver and power and run it from 63hz to 1khz and the midbass took a 30-40% hit in output, while losing clarity (began getting muddy down low). Then take it and ask it to play 80hz (because 63hz had no chance) and play it up through 3khz and your midbass was down another 25-35%, the midrange detail was lacking, and your overall midbass/low midrange lacked output and clarity, as well as any real snap.

The above time that I spent playing with my midbass in both a true 2 way and 3 way configuration (and most everything inbetween) really showed me the importance of assigning frequency ranges to drivers and picking drivers that perform the best in that range. By no means am I saying that you have to do 3 ways, although I have never heard a great 2 way system outperform a great 3 way setup.

With all of that being said, you still have to accept a lot of compromise in car audio. The less you are willing to accept the more time you have to spend in research, installation, and trial and error. IMO car audio has a couple of very key factors that need to be addressed, pathlength, power, and driver placement. Driver type and frequency range are also very important, but still secondary IMO.

Kinda rambled /shrug

Fej

 

Fej, you're absolutely right about the compromises. Some of them are unavoidable. Some appear unavoidable, but actually only require some knowledge and/or more work to overcome.

You hit the nail on the head regarding the band-limited reproduction. Most raw drivers (not the truly good ones) have a limited frequency band where they work most effectively and cleanly. That falls under what I was describing above. But pure frequency response is not the end-all be-all for driver selection. One has to consider many things about a driver's character before selection in a given situation. Most people don't understand the contributions of distortion, how response plots can be deceptive, and how these two things affect each other. They are not independent, and can't be treated that way. If you're selecting a driver based only on the manufacturer's response curve, you're missing half the story. These apparently small details are the difference between a truly great-sounding system and an average one (the vast majority of car audio).

A well-built 2-way will generally be better than the vast majority of 3-way setups only because most implementations of 3-ways are done by people who think more must be better, and really don't know what they're doing. One is not inherently better than the other, it's just that additional complications of the 3-way tend to make things worse instead of better. I've done lots of both and have found that it's almost always a far simpler thing to address the limitations of the 2-way than to control the additional issues created by the 3-way. Yes, the 3-way has tremendous potential to be better, but rarely does it happen.

FWIW, a true midbass should not sniff anything above 500 Hz. If it does, it's a low midrange or a bass-midrange, not a midbass. Car audio appears to have developed some of it's own strange rules that cause confusion when you consider where they came from. In home or pro systems, a midbass usually doesn't reach above 300 Hz or so. In fact, the last set of Focal 3-ways (car) I worked with had the midbass XO set at roughly 220 Hz.

 

I agree with what you are saying Spkr, but to clarify I am speaking about 2 ways vs 3 ways in the car environment only, and not in the home audio world. IMO anything beyond an MTM in home audio is making up for deficiencies in either the drivers, or the enclosure.

The benefits to a 3 way in the car usually stem from the problems with car audio in general, poor locations, the almost complete lack of the ability to build proper enclosures (unless you are doing a serious, hardcore install), location of the listener, location of the listener relative to the drivers etc etc. Limiting frequency ranges to an optimum range per driver almost forces you into a 3 way if you truly want to get to a "top level" of performance IMO. The 3 way also allows you to address the location and aiming issues that you are forced to deal with in a car when coupled with processing (which can be a blessing or a curse). You can also "fix" some of the problems with stage and imaging that you encounter in a car installs with a 3 way (A pillar tweets) that without a dedicated midrange and processing you cannot really attempt with a 2 way, where the negatives would outweigh the positives. And lets be honest, 8/10 people who want a 3 way setup in their cars are self installing and have some knowledge about how it works and what it takes to make it work (again processing).

Now with that being said I am quite happy with my 2 way setup from Pioneer in my truck located in kick pods. The near equal pathlengths made more of a difference in my stage than I ever would have thought, and when you couple the pathlength advantage with the drivers themselves being more on axis, it really is quite a solid improvement with minimal need for processing. Is the midbass as good as the 3 way in the vette? Nope. Midrange clarity (especially upper midrange) as good as the dome mid in the vette? Nope. But they do perform pretty damn well for a 2 way setup and are an acceptable compromise for me. And at the end of the day, that is what car audio is, a compromise

Fej

 

As much as I'm enjoying the back and forth here, we're going to have to start a different thread to keep at this.

Hehehe, ok. In my experience, most people can't mate a box and a sub on their own let alone properly integrate a 3-way system, so we'll have to agree that we have different opinions for what constitutes appropriate knowledge.

I'll start a different thread for us in a day or two, ok?

 

the tweets are flat, yes... but the mids? damn... I had to remove the carpet, then build up the area to accept the speaker. It wasn't fun... fibreglass, bondo...

it sure looks nice, tho.

As an aside, that was taken after the first attempt. I did it again to level off the mid-range.

 

No worries Spkr, really not arguing with ya. I guess I speak from an enthusiasts point of view, and a lot of my experience stems from an enthusiast level system in cars. Now granted I have helped dozens of friends, family, random people etc. tune whatever system they had to work with, but the only 3 way setups I have ever dealt with are from enthusiasts. I have never seen a 3 way setup in a car from someone that is not at least what I would call an "audio" person.

Really, audio has no true "right way". Watching live performances in intimate settings is about as close as it gets, everything else is either an attempt to recreate that setting, or create a version that is pleasing to YOUR ear. I feel in a car that can be reached with a 3 way setup on a level that I have not heard from 2 ways, even really high dollar ones. Scroll through the last 5-7 years of sound competition winners and you will find most of those winners run some version of a 3 way front stage. Hell some even run a 4 way front stage with a sub as near to the dash as possible.

Can 2 ways sound great? Yep I have a 2 way in my truck that I am really happy with, and it is not high dollar by any means. But IMO the frequency range is too large for the midrange by itself to excel at, so the low midbass suffers, and the upper midrange clarity and detail suffer. These deficiencies are addressed with a proper 3 way

I default to your superior knowledge about driver parameters, crossover design and impedance measurements and compensations. Very important factors in overall response and performance, but IMO not worth the effort in a car environment. So I attempt to build the best system I can with basically modified factory locations, clean power, and quality drivers tuned with my knowledge and experience, and most importantly my ears.

Fej