Any general bass anomalies in the E30 coupe?

[Alpine003]

I know some cars exhibit general bass dips/emphasis in certain frequencies regardless of what kind of speakers you use due to the nature of the acoustics.

Does anyone know or have measured consistent bass anomalies in an e30 coupe?(ex. 180hz dip at 12db/oct w/ a certain q factor...)

I managed to tweak my mids/highs but still not satisfied with my muddy mid-high bass.

[StereoInstaller1]

OK, so like if you are actually familiar with this stuff, let me throw what I know at you.

First off, let me say that I have never seen an actual transfer function plot of an E30....but....I have done at least 30 multi-amped sub/mid/high E30 installs.

Every damn one of them has had a HUGE suckout at about 100Hz, with a fairly shallow Q. I would say in the range of about 15db drop, minimum. These are one of the worst cars this side of a Mazda 929 to exhibit "tinkle and boom".

All of that vertical glass make a enormous spike at about 3.5Khz, with attending sub-harmonics at (duh) about 1.75Khz and harmonics at 7Khz. I would guess the entire treble region to have at least a 8 to 10db spike between 2K and 8K...add a very aggressive tweeter placement (stock) and you get sizzle from hell, with massive sibilance (and listener fatigue) to go along with it.

These are tough cars to make sound good if you have high standards.

So far, I have relocated my ABS brain and started making my under dash cabinets to house the mid drivers. Tweeter placement on top of the dash but on-axis will commence shortly. Bass still frustrates the hell out of me. I have had 5 or 6 boxes in my car so far, and none have really worked.

This time I am going to do an impedance plot, see if I can flatten response with a combination of resonance tuning and Zobel networks, then tweak with the EQX that I am finally going to get use out of.

If you want a quick soloution to a decent improvement, get a pair of "Dynasorb" panels and mush them in behind your front mids, then apply any of the butyl-based damping materials on the kickpanel itself. Make sure the speaker is actually mounted over the dynamat, too.

HTH,
Luke

[e30 gangsta]

holy fuck. You tottaly lost me.

[Alpine003]

OK, so like if you are actually familiar with this stuff, let me throw what I know at you.

First off, let me say that I have never seen an actual transfer function plot of an E30....but....I have done at least 30 multi-amped sub/mid/high E30 installs.

Every damn one of them has had a HUGE suckout at about 100Hz, with a fairly shallow Q. I would say in the range of about 15db drop, minimum. These are one of the worst cars this side of a Mazda 929 to exhibit "tinkle and boom".

All of that vertical glass make a enormous spike at about 3.5Khz, with attending sub-harmonics at (duh) about 1.75Khz and harmonics at 7Khz. I would guess the entire treble region to have at least a 8 to 10db spike between 2K and 8K...add a very aggressive tweeter placement (stock) and you get sizzle from hell, with massive sibilance (and listener fatigue) to go along with it.

These are tough cars to make sound good if you have high standards.

So far, I have relocated my ABS brain and started making my under dash cabinets to house the mid drivers. Tweeter placement on top of the dash but on-axis will commence shortly. Bass still frustrates the hell out of me. I have had 5 or 6 boxes in my car so far, and none have really worked.

This time I am going to do an impedance plot, see if I can flatten response with a combination of resonance tuning and Zobel networks, then tweak with the EQX that I am finally going to get use out of.

If you want a quick soloution to a decent improvement, get a pair of "Dynasorb" panels and mush them in behind your front mids, then apply any of the butyl-based damping materials on the kickpanel itself. Make sure the speaker is actually mounted over the dynamat, too.

HTH,
Luke

Thanks Luke for that insight as that was the kind of answer I was looking for. You are right about the midrange. I had to attenuate -8db from my Focals after I mounted the tweeter sails. The midrange seemed to work better all concentrated at the kicks(without the sails) but I noticed better soundstage and imaging with the tweeter sails.

As for the bass, I'm glad to hear that I'm not the only one frustrated with it after several tuning sessions. I hope someone can find the magic combo soon. I currenlty have my Alpine HU boosting +3 at 90db at a Q factor of 2 but anymore than that and it gets too muddy.

Funny thing you mentioned the dynamat on the kicks as I've done that while I was installing my new components. What really triggered it was all the holes below the speaker on the metal. I placed some Dynamat in both the cavity and outside metal around the speaker. I also placed a small amount of fiberfill in there as well. I used weather strip to fill in the area around the wiring.

At this point, I'm almost pondering on brining my 5.25" all the way down to 60-70hz and use my sub for mainly sub bass use.

Please keep us informed on any findings. The tweeter on top of dash sounds like it can be a good idea. On a side note, I wouldn't mind having a tweeter setup like the $6700 Bang and Olfusen option on the new Audi A8. ;)

[StereoInstaller1]

I have been actually thinking about doing a "Quasi-Bandpass" subwoofer, with 2 different tuning frequencies, both ported through the rear deck. I figure something like 1 tuned at 32~35Hz, then another tuned at about 85, basically around the low pass crossover point.

Of course the woofer will fire through the armrest. I dunno, every since I quit smoking pot, I am just not as creative. 9 years is a long time though, so I am not gonna start again.

If you are talking about running the 5.25 Focals down to 70Hz, I sure hope your crossover is 24db/oct or better, or you are OK with 100db or less!

that B&O Audi is interesting! Stolen directly from Earl Zausmers' E34, way back in about 1992. Neat to see motorized tweeters in the dash like that.

Luke

[auto da fe]

My radio won't turn on.

[NC325iC]

start a new thread

[LEANE30]

what is the best location for a truck sub box considering the poor acoustics? i personally do not have a trunk skipassthru and have been pondering the best way to go about the design, i'm planning on running just one 10" and bolt the amp to the exterior of the box itself....(minimal weight addition, i'm just looking for good full sound, not necessarily max DB)

StereoInstaller, do you have any experience with laying out a verticle rear deck port and a downward firing sub? (usingthe trunk floor as a backwall?) i have been also pondering a hanging box design ...what is the ideal box volume to house one 10"?

[MikeE30325i]

i put my 8" bazooka tube behind my passenger seat, and it is fine for me. bass hits hard and people outside know you have something.