Hey Everyone,

I have a question about an audio upgrade I'm planning, specifically about wiring the 3.5" and 5.25" speakers up front. I've been combing the forums, and have found a lot of great info, but I'm still not clear on a couple of things.

The plan is to have a 4-channel sub, 2 channels driving new 5.25" speakers in the doors, and bridged to drive a 10" sub in the trunk. I'm also hoping to swap out the 3.5" for some higher quality speakers.

My question (it may be a dumb one) is can I wire the 5.25" speakers to my amp while leaving the 3.5" wired to the factory head unit? The reason I ask is I purchased an Integral Audio harness (off amazon) to get access to the head unit output via RCA, as well as to tap into the door speakers. I only see two pairs of speaker wires on the harness though.

I guess I'm asking if the 3.5" speaker wiring is separate from the 5.25" wiring (are both present, and separate, in the x3991 connector?)...

...and can I leave the 3.5" connected as-is (just swapping the actual speaker itself) while only tapping into the 5.25" speaker lines to connect to the amp?


Thanks in advance!

Best,

Brian Harms

 

If you have the standard 6-speaker system then they share the same wiring (connected in parallel), and the connection is available in the X9331 harness. To have independent wiring connections you'd need to run new wiring into the door. Not impossible, but not super easy either. My recommendation in this case, if you are trying to keep costs down, would be to put a 2-way component set in the doors, mounting the tweeter where the 3.5" is. Not ideal, but better than the alternatives if cost is an issue.

If you have the HiFi or HK systems, you'll have direct wiring access to each speaker from the HiFi or HK amp. The speaker connection in the X9331 harness does not apply in this case.

 

Thanks for the quick reply!

OK so it is what I suspected. Would it be silly to just wire the new speakers in parallel? My amp is stable down to 2 ohms (maybe 1 actually if unbridged). I wouldn't be opposed to this as long as the sound quality wouldn't be significantly inferior to the component setup. I just think I remember one or two threads where people put components in and there were several comments about the placement being odd for sound quality.

If one were to do this, would I just need to look for speakers with similar RMS values? Or would they need to be identical?

Thanks again,

Brian harms

 

So after a quick look at Crutchfield I believe I've answered my own question. Looks like the Watt rating for all of their 3.5" speakers are 50 or less, so if I wanted to wire the door in parallel I'd have to choose a much less powerful 5.25" speaker to match ratings... Not going to happen.

Although what are the specs on the speakers used in your Soundstage that let them be wired up together?

I'm not totally opposed to the tweeter in the upper slot. In your experience, has this ever created strange sound qualities?

Thanks,

Brian

 

The power rating (watts) of the speakers doesn't matter, as long as you don't exceed it. Resistance (ohms) does matter, in this case you'd need to use at least 4ohm speakers to remain above a 2ohm load to the amp.

The problem with wiring two sets of speakers up in parallel in this situation has to do with the fact that they would both be receiving/producing the same, overlapping sets of frequencies. This results in something called comb-filtering. Since both speakers are producing the same frequencies but from different locations, you get peaks and nulls as frequencies combine, in and out of phase, cancelling and adding to each other. Envision dropping two stones into a pool of smooth water at the same time. Think about what happens when the two sets of waves start to meet each other. That's what's happening here, only much, much worse: It's happening at an infinite number of frequencies between 20Hz-20kHz, and instead of just happening in the 2D plane of the water surface, it is happening in the incredibly complex 3D space of the vehicle interior. This is what comb-filtering looks like:



The peaks are as high as +6dB, and the nulls are complete cancellation. Not pretty. The locations of the centers are a function of the frequency, the distance between the speakers, and the listener distance from each.

This isn't an issue with our Soundstage, because the speakers aren't wired in parallel. We sized the PCB of our vehicle-specific crossover for the midrange and midwoofer to fit into the armrest cavity. The crossover divides up the frequencies, applies some shaping, and then delivers it to the individual drivers. The tweeter doesn't share the door wiring, and so we have a separate tweeter-only crossover that installs in the sides of the dash.

If you use a 2-way system with the tweeter in the midrange location, and find a location in the door for the crossover, you won't have the comb-filtering issue described above. It isn't ideal: you are burying the critical vocal midrange band at the floor, and the tweeter location is too low and will be heavily influenced by knees/etc in the way. But it is far, far better than trying to wire up two different speakers in parallel.

 

Kevin,

Thanks again for your clarification. Not having done any audio upgrades before it's been very helpful.

I've gone ahead and ordered some component speakers to do just as you suggest. I'll have to dig up that other thread where the guy did a similar thing (and fabricated the mounting brackets himself).

Cheers!

Brian

 

EDIT 1: oh jeez the resolution on these images is horrible. Is that a NAM limit or something? Let me try uploading those again.

Edit 2: Ok I just pasted links to the images in my dropbox. Hopefully they are readable.

Kevin, thanks again for your help. I'm going to be starting my install soon and I have a quick question. I ordered the harness you guys are selling on Amazon and it looks a bit different than in the picture I saw. I think I know what to do but I wanted to check with you before I snip anything. Could you take a look at these pictures and make sure they look right?

Dropbox upload attempt:

https://www.dropbox.com/s/io7rog412q...2022.45.41.jpg



Also, it looks like the two rca pairs are both front channels. So I can just ignore one pair, run one red/white cable to the amp, and then use a couple splitters at the amp to divide into 4 channels?

https://www.dropbox.com/s/gad6escaon...2022.42.25.jpg



Thanks!

Brian

 

Brian,

That is all correct. I'm assuming you must not have received the instructions pdf via email (spam box maybe?). Here's a link:

http://www.integralaudio.com/install...structions.pdf

 

Perfect, thanks! Yeah it must have gotten lost somewhere in the interwebs.

Cheers!

Brian