Pioneer 8 inch sub in 4th gen?

Well, right now I can't find the pics I took, and I'm getting ready to deploy, so it may be a while before I can get some new pics of it. Sorry. The clock is ticking & I've got a bunch of things to do before I go...
:bash:
 
Just out of curiosity, does anyone know how much the JBL sub box would run (no amp, unloaded if possible would be best)?
 
well, my friend just gave me an old soundstream 8 inch sub, which i measured from top to bottom is a bit less than 4 inch, so since it is a freebie here for me, i'll try to swap it in and see how's the sound quality on that without adding a new amp.
 
A/V1 said:
Hello. I got that same exact sub, and going from the 2 ohm output to the 4 ohm sub was a huge disappointment. You can barely hear it. The OEM sub was also a dual voice coil, and this one is a single. I ended up selling my OEM nav and went aftermarket (with an aftermarket amp for the sub as well) so I can't help out with how to alleviate the problem using the JBL amp.

You might be able to simply run the sub output of the JBL amp to the input of an aftermarket amp (high in), then run that to the Pio sub.

Good luck.
Click to expand...

I like how the pioneer is so thin to fit in our stock sub location. I am wondering if i need to have an aftermarket HU if i have the pioneer sub and new amp for it? I would just like to control the bass to the sub without killing my stock speakers.

My other option is to do as you did and get the aftermarket HU with the sub/amp. Did you keep the stock speakers? at this point it might just be worth it to change them out. Also did you install your self? These guys around here are killing me with there install prices. What should it run me to put in the 8" pioneer with a decent amp? if thats even possible. And sorry for the questions as you can see im a noobie at this stuff. Any advice would be greatly appreciated.
 
just an update that i am not wasting my time to replace the soundstream sub in place. the sound quality is going to be worse than stock JBL sub due to the difference in ohm. and i cannot spare any space in the cargo area to fit in an extra amp cuz i need cargo space for carrying stuff.
 
Stock wiring and dvc to svc conversion?

riverwolf said:
A clarification for a few comments in this thread.

The Stock JBL Synthesis sub is DVC and the stock amp dedicates *2* channels to the sub...one per coil at 45 watts each.

You need to remove the whole side panel and then some to get to the sub box. Access instructions. .

The sub enclosure is .6 ft^3 according to the original Toyota sales information kit that was posted on the forum back when the 4th Gen launched.

If you do a bit of searching, you should be able to find installs where folks have used Polk, Rockford Fosgate, and Elemental Designs 8" subs in the stock enclosure with the stock amp.

A manufacturer's power rating neither means the driver *requires* that much power nor that it will really handle that much power. Real world power handling is nearly always excursion limited unless the box is way undersized...excursion for a given power input varies with frequency and enclosure volume.

Thermal power ratings (what most driver power handling specs really refer to) has nothing to do with sensitivity. Two drivers with the same sensitivity rating could have different thermal power handling limits because of the marketing guys or due to longer vc, thicker gauge wire used for the same length vc, different material used for the vc wire, better air flow in/around the vc, etc.

-Brent
Click to expand...

Sorry to dig up an old thread on a topic that's been beaten to death, but my searches didn't lead *me* to any concrete conclusions. I may just be dense..:(

The stock sub is a dual voice coil, with each voice coil running at 2 ohms (each vc with it's own discrete wiring)?

Thus, is the stock amp expecting a 2ohm load from each pair?

Or is it wired as a 4ohm load split between each vc to make 2ohms total?

Bottom line is: if I get an 8" shallow 2ohm single voice coil replacement sub and wire it so both channels go to the one voice coil, will that then create a 1ohm load and risk blowing the stock amp, or will it just double the power and still maintain a 2ohm load w/ up to 90watts rms?

Thanks for helping clarify -- it's a bit confusing to me.
 
nightshade000 said:
Bottom line is: if I get an 8" shallow 2ohm single voice coil replacement sub and wire it so both channels go to the one voice coil, will that then create a 1ohm load and risk blowing the stock amp, or will it just double the power and still maintain a 2ohm load w/ up to 90watts rms?

Thanks for helping clarify -- it's a bit confusing to me.
Click to expand...

If you do this, you'll likely destroy the amp since you'd be connecting two outputs directly to each other.

The stock sub has two voice coils, as do all DVC drivers. One channel of the amp is connected to each coil.

Assuming a JBL Synthesis amp, you have 8channels total. FR/FL/C/RR/LR/Sub/Sub. The "tweeters" in the way back corners are wired in mono for the 8th channel.

If you just try to replace the driver, your overall system may be out of balance since the OEM amp has no gain controls that I'm aware of. The replacement driver may be capable of more output and/or lower frequency response, but likely at the expense of efficiency. Hoffman's Iron Law of subwoofers low/loud/small, pick 2. Picking random numbers. Say the stock amp driver plays the low note on a bass guitar at 90dB with a volume setting of 30. Your replacement driver might only produce 85dB for the same volume setting, but your main speakers will still be playing 90dB...and you'll think your new driver sucks, when the driver may be perfectly capable of playing much louder than the stock JBL if given enough power.

The only real relevance of the OEM driver being 2 ohms per coil is the stability of the amp and the power a driver will draw from the amp. With the OEM amp rated to safely deliver 45wpc@2 ohms, it will likely produce 25-30 watts into 4 ohms. While not done often in auto sound, you could technically wire up an 8 ohm speaker with the likely output maxing out around 15 watts or so. Any amp can be used with a higher impedance load than spec'd, but not lower due to potentially too much current draw. Theoretically, an amp should double its output wattage when the impedance is halved, but it's a bit less in reality since we don't have an infinite power supply, wire resistance, etc.

-Brent
 
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riverwolf said:
If you do this, you'll likely destroy the amp since you'd be connecting two outputs directly to each other.
Click to expand...

Thanks Brent

.. I guess no amount of wishful thinking will get around the consensus that their really isn't a satisfactory way to replace the stock sub without adding an separate amp until someone develops a shallow mount, 8", 2-ohm dvc sub.
 
nightshade000 said:
Thanks Brent

.. I guess no amount of wishful thinking will get around the consensus that their really isn't a satisfactory way to replace the stock sub without adding an separate amp until someone develops a shallow mount, 8", 2-ohm dvc sub.
Click to expand...

The physical driver's not really the problem. I think the usable depth was in the 4.5"-4.75" range without needing a spacer...measurements were posted in several threads years ago, but I don't know if they still exist. Rockford and Kicker both make 8" DVC 2-ohm drivers that should fit the enclosure's depth. Elemental Designs also has a driver that looks like it should fit and can be ordered with 2 ohm coils. Based on the specs alone, I would expect the eD to be a better driver...lower Fs and more Xmax, but it probably "wants" a larger enclosure based on the difference in Vas compared to the RF/Kicker.

The problem is how much output each driver will produce for a given wattage compared to the OEM sub. We can use software modelling on the aftermarket drivers, but we don't have the necessary parameters for the JBL to compare to.

Let me try a different tack to explain the potential issue. At its simplest, an amplifier just takes a small input voltage and makes it bigger. It doesn't care what driver is attached, it's going to amplify the incoming voltage from the head X times up to the limits of its power supply. With the OEM amp, this multiplier is fixed while aftermarket amps give you control of the multiplier (gain control). The problem then becomes what the driver does with a given output voltage. Even if the RF/Kicker/eD drivers' impedance is exactly the same as stock, they could produce less output due to a heavier cone, voice coil former, stiffer spider, or other driver parts that effect cone movement, resulting in a bass shy spectral balance. There's also the potential that one or more will actually be more efficient (louder) than the OEM driver, producing a bass heavy balance...we just don't know.

In the end, it looks like a lot of work for a project without predictable results. The only way to "guarantee" the outcome of a replacement driver in the stock enclosure is to use another amp with hi-low conversion off of the stock amp's sub channels. This new amp would give you the necessary gain controls to balance the new sub with the main speakers. As mentioned above, you're looking for a driver that plays nice in 17 liter (.6 ft^3) sealed enclosure. I would spend time with something like WinISD Pro running my own simulations from drivers' T/S parameters as opposed to depending the manufacturers' enclosure recommendations to choose a suitable driver.

-Brent
 
Great info

riverwolf said:
The physical driver's not really the problem. I think the usable depth was in the 4.5"-4.75" range without needing a spacer...measurements were posted in several threads years ago, but I don't know if they still exist. Rockford and Kicker both make 8" DVC 2-ohm drivers that should fit the enclosure's depth. Elemental Designs also has a driver that looks like it should fit and can be ordered with 2 ohm coils. Based on the specs alone, I would expect the eD to be a better driver...lower Fs and more Xmax, but it probably "wants" a larger enclosure based on the difference in Vas compared to the RF/Kicker.

The problem is how much output each driver will produce for a given wattage compared to the OEM sub. We can use software modelling on the aftermarket drivers, but we don't have the necessary parameters for the JBL to compare to.

Let me try a different tack to explain the potential issue. At its simplest, an amplifier just takes a small input voltage and makes it bigger. It doesn't care what driver is attached, it's going to amplify the incoming voltage from the head X times up to the limits of its power supply. With the OEM amp, this multiplier is fixed while aftermarket amps give you control of the multiplier (gain control). The problem then becomes what the driver does with a given output voltage. Even if the RF/Kicker/eD drivers' impedance is exactly the same as stock, they could produce less output due to a heavier cone, voice coil former, stiffer spider, or other driver parts that effect cone movement, resulting in a bass shy spectral balance. There's also the potential that one or more will actually be more efficient (louder) than the OEM driver, producing a bass heavy balance...we just don't know.

In the end, it looks like a lot of work for a project without predictable results. The only way to "guarantee" the outcome of a replacement driver in the stock enclosure is to use another amp with hi-low conversion off of the stock amp's sub channels. This new amp would give you the necessary gain controls to balance the new sub with the main speakers. As mentioned above, you're looking for a driver that plays nice in 17 liter (.6 ft^3) sealed enclosure. I would spend time with something like WinISD Pro running my own simulations from drivers' T/S parameters as opposed to depending the manufacturers' enclosure recommendations to choose a suitable driver.

-Brent
Click to expand...

Brent -- Great info! If this had been stickied and I wasn't piecing together a lot of disparate info/posts, it would have saved me a lot of time in research I only half understood. :)
 
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