Perfect Midbass - an unusual approach

[madstamm]

Midbass using a huge PA driver
Hello everyone...

STATUS QUO
- am starting a car from sratch (95 Renault Clio Williams) and am making system choices, specifically midbass right now.

WHERE I'M HEADED
- system has to be novel in looks and sound
- leaning towards a super-high efficiency setup, to get that "effortless" sound... (possibly horns, but looks to be extremely tricky business in-car)
- purposely looking for cheap tricks (anyone have ideas for cheap damping material i can get at in europe???)
- want the midbass to be able to compress the chest cavity to uncomfortable levels

IMMEDIATE CONCERN
10-12" PA speaker running ~80(-) to 500(+)Hz in fibreglass door panels
ex) http://www.partsexpress.com/pdf/264-343.pdf

QUESTIONS

- has anyone seen or done an installation with drivers of this size in doors, heard of someone doing it, and can warn me about some for sure to come problems? (aside from the obvious need to completely redo the entire door) Im looking for imaging issues, driver recommendations, etc...

- at what frequencies does directivity really start to hurt in a car? ie with the driver liked to above, there is 3dB loss at 45deg when above 500Hz... what can the ear typically tolerate inside a car? I just did my second kickpod install with CSS FR125S 4"ers... sounds lovely when you move your head right on-axis, but they dont image at all when positioned normally... so im a little "antsy" about going nuts with the doors just yet...

THANKS!
for any help... 'be much appreciative to hear from you guys!

cheers,
mike

[peter_euro]

Originally Posted by madstamm

Midbass using a huge PA driver
Hello everyone...

STATUS QUO
- am starting a car from sratch (95 Renault Clio Williams) and am making system choices, specifically midbass right now.

WHERE I'M HEADED
- system has to be novel in looks and sound
- leaning towards a super-high efficiency setup, to get that "effortless" sound... (possibly horns, but looks to be extremely tricky business in-car)
- purposely looking for cheap tricks (anyone have ideas for cheap damping material i can get at in europe???)
- want the midbass to be able to compress the chest cavity to uncomfortable levels

IMMEDIATE CONCERN
10-12" PA speaker running ~80(-) to 500(+)Hz in fibreglass door panels
ex) http://www.partsexpress.com/pdf/264-343.pdf

QUESTIONS

- has anyone seen or done an installation with drivers of this size in doors, heard of someone doing it, and can warn me about some for sure to come problems? (aside from the obvious need to completely redo the entire door) Im looking for imaging issues, driver recommendations, etc...

- at what frequencies does directivity really start to hurt in a car? ie with the driver liked to above, there is 3dB loss at 45deg when above 500Hz... what can the ear typically tolerate inside a car? I just did my second kickpod install with CSS FR125S 4"ers... sounds lovely when you move your head right on-axis, but they dont image at all when positioned normally... so im a little "antsy" about going nuts with the doors just yet...

THANKS!
for any help... 'be much appreciative to hear from you guys!

cheers,
mike

run your mids from ab 60-180 instead of what you listed... Much harder to do doors, you better be good with glassing and make sure you have enough volume plus solid enclosure to door sheetmetal mount. Unless you run 18in subs, 12in mids would be too overhelming.

[Hautewheeler]

you might look into using large "musical instrument" woofers. They offer a great big frequency range, and usually have good sound dispursion, and it would be easy to use crossovers to get rid of the unwanted frequencies. Plus, the musical woofers are usually very power effecient and can be had for cheap

Your doors are going to have to be very sturdy (obviously) and you might incorporate an agressive angle into your panel design, since (if my memory serves correct) a renault clio door ends about mid upper arm and begins the window, but you want the sound to hit the ears, and not the elbows, right?

I wonder if anyone has ever fooled around with using linear transducers in car audio yet? - I think that would be impressive!

[Hautewheeler]

whoops! just saw the link.. guess that is a musical instrument woofer..huh?

Hautewheeler strikes again

I'd say stay with 8's or tens, definitely.. 12 would be pushin it, and you'd probably end up replacing lotsa windows. I'm actually in the process of getting an off -the -wall 8" component set together for my truck, and I have the same concern with the doors of the f150 being made of such flimsy sheetmetal.

[The Viking]

Just a few suggestions here.........


I have done many systmes with KILLER midbass performance, and in my opinion, that is harder to do than just about anything else in the mobile enviorment.

Reason being is due to the frequency and the wavelength in the car, then to add onto the issue they are generally in the doors firing into each other, not good for the most part.

If at all possible, when you build your new door panels, be sure to angle them on axis towards each front seat as much as possible.

Also run them at a lower fequncy like was stated above, But here is the ral issue, when the sub bass and midbass overlap in fferquencies, that is when **** really gets funky and hard to make sound good....phase cancellation.....


Use steep roll-offs and stager the frequencies somewhat, experimintation is the key, you WONT get it rightthe first time!


Another thing you might consider, put the nidbass drivers in the floor, just in front of the seats, in a fibreglass enclosre cut into/mounted to the floor. Have done a few smaller vehicles this way and gotten excellent results.


I could go on and on about this, but just wanted to state a few things I have learned over the years

[ramos]

^ very good points. aiming in particular as the frequencies mid drivers will be playing are the most directional by nature

[peter_euro]

Originally Posted by The Viking

Just a few suggestions here.........


I have done many systmes with KILLER midbass performance, and in my opinion, that is harder to do than just about anything else in the mobile enviorment.

Reason being is due to the frequency and the wavelength in the car, then to add onto the issue they are generally in the doors firing into each other, not good for the most part.

If at all possible, when you build your new door panels, be sure to angle them on axis towards each front seat as much as possible.

Also run them at a lower fequncy like was stated above, But here is the ral issue, when the sub bass and midbass overlap in fferquencies, that is when **** really gets funky and hard to make sound good....phase cancellation.....


Use steep roll-offs and stager the frequencies somewhat, experimintation is the key, you WONT get it rightthe first time!


Another thing you might consider, put the nidbass drivers in the floor, just in front of the seats, in a fibreglass enclosre cut into/mounted to the floor. Have done a few smaller vehicles this way and gotten excellent results.


I could go on and on about this, but just wanted to state a few things I have learned over the years

aiming drivers toward a single center point of the front stage works better actually... Also, keeping signal path lengths more or less the same helps a lot due to loudness being directly proportional to the distance from the speakers to the listener (the closer the speaker, the louder it will appear). Putting midbass in the floor is a real bad idea IMO, midbass is directional enough and firing speakers in the way the signals cross, can create tonal nightmare... If you are able to install a sub or two up front and lo pass them below directional region, this would be great (in the floor or center console) but placement and aiming of midbass drivers should not be any different than other speakers. The only effective way to get good midbass is to run it in sealed enclosures and betw. 8-10in in diameter and plenty of power.

[The Viking]

you are correst in some of what you say petr euro. However, when discussing midbass, i am talking about frequencies in the range of "about" 80-200 Hz. There is not enough stereo or imaging information in those frequencies to matter where it comes from. (left/right that it) What is critical is placement close in conjunction with the upper frequency drivers, which are up front creating the soundstage. The human ear will percieve the strike of the snare or tom as left or right from the upper frequencies they produce, and the impact will be created by the midbass drivers, so whether they are in the doors, on axis, in the floor under your legs or in the dash, they will perform well as long a a little thought is put into it..

[peter_euro]

Originally Posted by The Viking

you are correst in some of what you say petr euro. However, when discussing midbass, i am talking about frequencies in the range of "about" 80-200 Hz. There is not enough stereo or imaging information in those frequencies to matter where it comes from. (left/right that it) What is critical is placement close in conjunction with the upper frequency drivers, which are up front creating the soundstage. The human ear will percieve the strike of the snare or tom as left or right from the upper frequencies they produce, and the impact will be created by the midbass drivers, so whether they are in the doors, on axis, in the floor under your legs or in the dash, they will perform well as long a a little thought is put into it..

I lo pass my midbass at 180... it is still directional and it still affects vocals

[madstamm]

thanks for all of your input guys...

my idea was to aim for the passenger head with the left speaker, driver's head with the right speaker... maybe a little above the heads... as much as possible of course.

as for equidistance: they will go into the corners as much as possible.

Both angle and position should not be a problem up to driver size of about 10" due to the clio's very forthcoming cabin...
however, just got a new problem:

CSS audio is selling the extremis 6.4 (6.8" driver, 25mm excursion ) at CDN200 a pair!! as a preorder...

this would not be keeping with the PA idea, but its such a great deal im not sure i can stick with the original idea here.. what do you guys think??