Speaker Upgrade

[Dylans95Chevy]

Looking to do the sound system in my truck. Already have a really nice Pioneer head unit. Im wanting the jl audio c2 series. I want to put the 5 1/4 in the rear instead of a 4x6 or 4 inch. Has anyone put bigger speakers in the rear and kept it looking factory? What size did you use?

 

[df2x4]

I've seen people do 5 1/4" round speakers back there, but it doesn't look anything close to factory. You have to mount them on top of the plastic trim to get enough clearance for the magnet. Looks strange IMO. Just go with a 4" in an adapter plate or a 4x6" speaker if you want the factory look. Adjust your high pass filter so they don't get any bass signals below 100Hz or so. You don't want a ton of sound coming from behind you anyway, your front speakers should be the loudest.

 

[Dylans95Chevy]

Looks like jl audio has c2 4 inch speaker. Ill be running the components up front and a jl audio 10 inch sub and a 5 channel amp.

 

[Brian9o12]

I have pioneer 6x9's in the back of my truck and 6.5s up front. No pics at the moment but they look pretty good


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[Dylans95Chevy]

I dont want to have cut plastic though.

 

[michael hurd]

Regarding rear speakers:

When you go to a concert, do you face the rear of the auditorium or venue, so the musicians play from behind you?

I highly doubt it.

Yes, you do hear a portion of reflected sound from the rear and the sides of the venue, however this is much lower in amplitude ( much quieter ) with an inherent lack of high frequencies, and delayed in time, as sound propagates at around 1125 ft/sec at room temperature.

Consider if you were in the close to the middle of the venue, 100 feet equidistant from the left and right speaker array, with the rear wall about 250 feet behind you. The direct sound would reach you from the speakers in about 0.09 seconds, then reflections from the rear of the venue would have traveled at least 600 feet to arrive back at you. [ (100+250) + 250 ]

The time of flight for a reflection would be about 1/2 second ( 600 / 1125 ) or 0.5333 to be more accurate.

High frequencies, with their short wavelengths will be absorbed simply through the sheer amount of people, and the thermals rising off of the packed crowd will cause the sound to be refracted upwards.

See the animations on this page, it will give you a better understanding of what refraction is:

http://www.acs.psu.edu/drussell/Demos/refract/refract.html

The middle animation is what I was talking about with the heat from the crowd, the same thing occurs at an outdoor concert, on extremely hot days or with wind gusts that can deflect the lobe of sound away from it's intended area.

Lower midrange and low frequencies have large wavelengths, and refract off of many more surfaces, with less attenuation than high frequencies.

Use the factory rear speakers for 'rear fill', upgrades are not needed here, unless of course the cone edge suspension is toast, or the coil is damaged. Turn them down in level compared to the front speakers, as they need not be very loud at all. With rear speakers producing high frequencies, the results are really not great, or 'realistic'.

 

[michael hurd]

I would put any money that you would spend on rear speakers aside, and use it for other things, like increasing the amount of sound abatement products, instead of 'rear speakers', unless the factory ones are non-functional.

Looks like Crutchfield pricing is around $ 140 bucks for a pair of the 4" speakers.... that can purchase a bunch of Dynamat or other like products, which will be of more benefit to your enjoyment, both with the sound system playing, and without.

 

[df2x4]

Regarding rear speakers:

When you go to a concert, do you face the rear of the auditorium or venue, so the musicians play from behind you?

I highly doubt it.

Yes, you do hear a portion of reflected sound from the rear and the sides of the venue, however this is much lower in amplitude ( much quieter ) with an inherent lack of high frequencies, and delayed in time, as sound propagates at around 1125 ft/sec at room temperature.

Consider if you were in the close to the middle of the venue, 100 feet equidistant from the left and right speaker array, with the rear wall about 250 feet behind you. The direct sound would reach you from the speakers in about 0.09 seconds, then reflections from the rear of the venue would have traveled at least 600 feet to arrive back at you. [ (100+250) + 250 ]

The time of flight for a reflection would be about 1/2 second ( 600 / 1125 ) or 0.5333 to be more accurate.

High frequencies, with their short wavelengths will be absorbed simply through the sheer amount of people, and the thermals rising off of the packed crowd will cause the sound to be refracted upwards.

See the animations on this page, it will give you a better understanding of what refraction is:

http://www.acs.psu.edu/drussell/Demos/refract/refract.html

The middle animation is what I was talking about with the heat from the crowd, the same thing occurs at an outdoor concert, on extremely hot days or with wind gusts that can deflect the lobe of sound away from it's intended area.

Lower midrange and low frequencies have large wavelengths, and refract off of many more surfaces, with less attenuation than high frequencies.

Use the factory rear speakers for 'rear fill', upgrades are not needed here, unless of course the cone edge suspension is toast, or the coil is damaged. Turn them down in level compared to the front speakers, as they need not be very loud at all. With rear speakers producing high frequencies, the results are really not great, or 'realistic'.

Super cool info as usual Michael. The time alignment issue you touched on is a much bigger deal than I once gave it credit for...

The Pioneer head units I have in my trucks (DEH-P880PRS) have tiny little microphones that you use for tuning purposes. You loop them around your driver's side headrest, connect them to the faceplate of the head unit, then start a diagnostic process on the head unit and get out of the vehicle (in a quiet indoor room). It goes through a series of clicks, white noise, and beeps through each speaker which takes about ten minutes. In the process, the system calculates the distance of each speaker from your listening position and adjusts output delay accordingly, while also making adjustments to your EQ. The Auto-EQ features I'm not a huge fan of as I usually leave things mostly flat, but it does provide a good baseline to find your specific vehicle's resonant frequencies. The time alignment on the other hand, MAN that makes a huge difference. The first time I set one of those head units up and ran the procedure I was blown away.

I've seen a lot of home audio stuff that uses similar tuning procedures, some higher end Velodyne subs for example.

Back on topic for a second, I definitely prefer a nice pair of rear fill speakers, but I keep them turned down way low in the trucks. Like half the output of the front stage or less.

 

[michael hurd]

Super cool info as usual Michael. The time alignment issue you touched on is a much bigger deal than I once gave it credit for...

The Pioneer head units I have in my trucks (DEH-P880PRS) have tiny little microphones that you use for tuning purposes. You loop them around your driver's side headrest, connect them to the faceplate of the head unit, then start a diagnostic process on the head unit and get out of the vehicle (in a quiet indoor room). It goes through a series of clicks, white noise, and beeps through each speaker which takes about ten minutes. In the process, the system calculates the distance of each speaker from your listening position and adjusts output delay accordingly, while also making adjustments to your EQ. The Auto-EQ features I'm not a huge fan of as I usually leave things mostly flat, but it does provide a good baseline to find your specific vehicle's resonant frequencies. The time alignment on the other hand, MAN that makes a huge difference. The first time I set one of those head units up and ran the procedure I was blown away.

I've seen a lot of home audio stuff that uses similar tuning procedures, some higher end Velodyne subs for example.

Back on topic for a second, I definitely prefer a nice pair of rear fill speakers, but I keep them turned down way low in the trucks. Like half the output of the front stage or less.

RE: Home AV Receivers with Audyssey:

Great idea, and absolutely makes a difference.

That said, I have an ancient dinosaur that decodes 5.1 DD and DTS, and does not have Audyssey capability.

I do have my own calibration microphone, software, and associated equipment that I can manually optimize what Audyssey can and more.

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[michael hurd]

The software package I use is very powerful, however to understand what you are measuring, and interpretation of results takes literally years to master, you have to have a solid understanding of physics, acoustics, and math in order to utilize it.