Acoustic equalization in a vehicle, normal or faulty? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 2 Old 11-07-2019, 11:58 AM - Thread Starter
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Acoustic equalization in a vehicle, normal or faulty?

I need an expert opinion. The audio system in my vehicle, which is new to me, does not sound like it is functioning correctly. What I perceive is that there is very little midrange coming out of the system. I do not have experience in development or tuning of acoustics in a vehicle and so I would like to hear the opinion of experts on this question: Are the frequency response curves that I have attached the result of a correctly operating system, or is the system likely faulty?

These measurements were made by attaching an audio oscillator to the aux input of the head unit, and then plotting the response at four speaker locations. The larger "door" speakers were replaced by resistor loads for these plots, but this was difficult for the dash tweeters, so I left the speakers as loads. The responses are measured using an audio voltmeter connected across the loads. Both the audio oscillator and the audio voltmeter have flat frequency response.
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post #2 of 2 Old 11-21-2019, 11:44 AM
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Well that's not a very good looking plot, but if it's a 2-way system, all the drivers seem to be working even if there does seem to exist a major dip in the upper bass and midrange. You took each measurement under similar conditions? I'm curious why the woofers are so different. Are they even the same woofer in the 2 doors?

Generally I don't expect a person who installs Rockford Fosgate equipment to do a good job setting it up because that's not a respected brand. It's a well-known brand, yes, but it's not very good. Their cheap products suck and their decent products are overpriced for what you get. But the bigger issue is that if someone's like "YEAH I'm gonna buy some Rockford Fosgate stuff for my truck!" you probably don't want that person anywhere near your truck. A good installer could make RF components sound decent or even good, but I don't think most "good installers" would be installing RF to begin with.

It is definitely the case that stock systems put very little thought into audio performance and problems like air leaks in the door (since the woofers don't typically have a sealed chamber in most vehicles) can definitely mess with your overall response.

At this time I'm not able to tell you if something is blown or if this is just relatively cheap stuff installed by someone who did not tune the system. Would advise visual inspections. And just to confirm, even though I read something about you taking each measurement at that speaker... you did, right? The two woofers were measured under the same condition (i.e. you mirrored the position at which you measured)?

I'd try swapping your left and right channels and see if it makes the graph swap.

(Also... since when did this forum have a car audio section!? I don't remember seeing it before.)

Last edited by DonoMan; 11-21-2019 at 02:50 PM.
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