Hi all,

This is my first on the forum so please bear with me. I just installed a bass tube in my hatchback Toyota Yaris, the Pioneer ts-wx20lpa http://www.pioneer.eu/eur/products/archive/TS-WX20LPA/index.html. The sub is hooked with the factory oem h/u, therefore I installed a high/low converter, the exact model being this one XScorpion LC09 http://www.sonicelectronix.com/item_40150_Xscorpion-LC09.html . The power cable is a standard cable which came with the sub and is directly connected with the car battery (no capacitor or fuse). The sound is quite good and solid considering it is a bass tube, however I notice that at certain very low frequencies the bass response suffers and the sub starts to struggle. For example take Phil Collins - In the Air tonight, that deep bass hardly comes out at all. Gain on the sub is at almost half way, maybe pushed a little more, 1 o'clockish

I would like any suggestion from you experts if I can do anything to improve my setup and improve my frequency response. Thank you

Welcome to the forum. I could find no mention of the frequency response of the Pioneer. Very odd. There could be a number of issues here. First, your signal you tapped into for your RCAs could be filtered and not passing the lower frequencies. Your RCA adapter could be suspect. Cheaper ones usually don't work too well and given the amplifier on the Pioneer has speaker level inputs, you'd be best off using those. It's just one less thing to go wrong. You could also have the crossover on the Pioneer set incorrectly, a cancellation issue, or it just simply may not dig that low.

I'd start by checking the filter on the amp and adjusting it all the way to the right. See what happens. If that does nothing, I'd move the tube around to rule out cancellation issues, if that doesn't work, remove the adapter. You see where I'm going with this?

I agree with Tirefyr. Use the speaker level inputs. Most of the "affordable" RCA adaptoers are iffy at best. I recently installed an Infinity Basslink in a friend's Hyundai Santa Fe. He opted to keep his factory radio, and we had better results using the speaker level inputs on the Basslink. He really enjoys the sound of that Subwoofer. He listens to Jazz, Blues and older Metal (Judas Priest, Ozzy, Dio..). He wanted his vehicle to sound like his home stereo. That's what he got. It sounds clean and tight. It's definitely NOT a window shaker. It just sounds good. I think you'll enjoy that Pioneer sub once you get it set up right. Have fun tweaking!

Many thanks for your responses Tirefryr and Teambrownnote. First off I checked the manual of the sub and it stated that freq. response is 25-200hz, so I guess it goes a bit deep. I perfectly agree that I can start off by playing around with the filter on the amp and moving the sub around. The next step I can't really understand (excuse my ignorance, I am a complete beginner to the sound mod scene); so you're suggesting that I directly connect the sub to the rear output of the oem h/u and eliminating the hi/low converter. What kind of cable do I require to do that?

I also forgot to mention that I have the rear speakers sharing the same output of my sub. The exact model of the oem h/u is this : W58824 (seem to be from Panasonic).

Thank you for your assistance

That frequency response is the -3db response of the driver itself, or where in free air the response dips down by 3db. It is in no way representative of how that driver plays in the enclosure. The enclosure a subwoofer is mounted in and how it is built and designed is what decides the outcome of its response.

As for the wiring, you simply run some speaker wire from each of the rear speakers to the speaker level inputs on the amp. You should have already done that for the low level converter, so just take those wires and go directly to the speaker level inputs on the amp.

Cheers guys, I just played around with the filter knob and moved the sub around, sq is already better. Didn't have time to hook the speaker wires to sub (thanks for your input Alton, now understand what the other meant), my next step will be to eliminate the RCA adaptor. Also I have the gain input centred at half with bass eq at -5 db from h/u. Do you think this is a good good setting for the sub ?

Cheers guys, I just played around with the filter knob and moved the sub around, sq is already better. Didn't have time to hook the speaker wires to sub (thanks for your input Alton, now understand what the other meant), my next step will be to eliminate the RCA adaptor. Also I have the gain input centred at half with bass eq at -5 db from h/u. Do you think this is a good good setting for the sub ?

You're on the right track, ea25. As far as settings go, you're kind of at odds with what the factory speakers can handle. In the Hyundai (and other vehicles with factory speakers I've worked on) we adjusted the h/u settings to get the best sound possible at a comfortable volume level, then dialed in the Basslink to add to the bottom end. Turned out quite nice, actually. The owner can get a little blurring in the rear view mirror...

Keep experimenting. Keep in mind, that if you ever replace the factory speakers, you'll be tweaking the subwoofer again. Keep us updated on your progress!

Yeah, in fact I already started looking for some 6.5 comps. So far Hertz and Focal Access are on the league, but anyways I shall discuss those on another thread. Btw the rca adaptor seems to have a "Signal Adjust" on it. Do you think I should play around a little with it as well before removing it completely?

That's just going to adjust output voltage. You can mess with it if you want, but I would just eliminate the thing.

Yep in fact I just lowered the output voltage for each channel a little, and increased the gain from the sub amp. But overall sq remained the same. Tomorrow I'll buy some speaker cable and try to hook it directly as suggested. Btw while I was tweaking I noticed that the backside of the head unit became rather hot after about half an hour. Is this normal? Thank you guys for the time being

Edited February 6, 201213 yr by ea25

i assume the hu heating up is nothing to worry about. if you notice a change in sound quality from speakers (increased distortion) then the hu is getting too hot. double check ground/power connections as well.

Cheers Lithium, will do

Yep in fact I just lowered the output voltage for each channel a little, and increased the gain from the sub amp. But overall sq remained the same. Tomorrow I'll buy some speaker cable and try to hook it directly as suggested. Btw while I was tweaking I noticed that the backside of the head unit became rather hot after about half an hour. Is this normal? Thank you guys for the time being

How hot are we talking? It is normal to get warm, but very hot is not good.

Actually not all of the h/u gets hot, but there is a metal plate on the back which definitely exceeds the degree of "warm". But I haven't noticed any distortions or other symptoms from the speakers.

I also tried to hook the sub directly to the h/u but it seems it is turning out into quite a complex task (for my newbie standards at least). Well the 4-pin speaker line input cable which was supposed to come with the sub is missing. I tried to contact the shop where I bought the sub from and told me it will take more than a month to arrive! Therefore I went to the computer store and bought a normal 2x2 molex connector (the likes of this one http://www.atmarkit.co.jp/fsys/cableconnect/09power/04power_atx12v-cbl-l.jpg ) However I would like to confirm from you guys whether it is up to the job quality wise. The cable is 16awg and I am planning to connect it to some normal speaker cables.

Thank you and sorry once again for my newbiness

For that connection it will work just fine. Not nearly as critical as the power and ground connections on the amp for example.

Thank you Alton. So now I spliced the wires of the 2x2 plug and connected longer speaker cables so that I can get coverage from the rear of the car (Sub) to the front (h/u). However, when I plugged the 2x2 into the terminal into the sub I noticed that the upper cables (the black ones) are corresponding to the + input. Aren't the black cables supposed to be negative ones ?! Thought I just ask before removing the adapter and start connecting from the h/u side

The wire color isn't relevant. Just make sure that you are connecting the positives and negatives (at the amp) to the correct wires at the deck. The manual for your Pioneer powered sub should show which leads are positive and negative (possibly marked on the amp itself?). It's not likey

that the molex plug you purchased at the computer store has the exact same colored wires as the original Pioneer plug anyway. Do you know which leads to connect to at the h/u?

Thank you for your input teambrownnote. From the h/u side it should not be a problem, I already have +/- marked as they are connected to the RCA adapter. However strange as it may seem on the sub they are not marked neither on the manual! However I found the Alpine MRV-100M which has an identical socket to my sub (2x2 and same alignment). On the manual of the alpine + are marked as the upper row. Can I assume that the same applies to the pio ?

Ok managed to find the datasheet http://www.eserviceinfo.com/download.php?fileid=58405 and interpret the polarity of the sockets. Yep, upper seems to be positive. Will set it up tomorrow and see how it goes

good luck with your testing

Damn, I ran into another problem guys.

So I checked the wiring diagram of my yaris. It seems that the guy that fitted the LOC connected the + out (according to the diagram) from the h/u to the - in on the LOC and vice verse. Should I stick with the wiring diagram? The other thing is that the wiring diagram is for the yaris 2007 in general (which is the model of my car of course), but factory stereos fitted in the yaris vary from region to region. The exact model of my h/u is a Panasonic W58824. The pins and cable colours also match from the wiring diagram I found to the actual pinouts on my h/u.

Any suggestions appreciated. Thank you

Here is the back side of the h/u if it might be of any help

The blue socket appears to be for speakers, the one next to it (black, yellow, red, white) is power, and the big black line is antenna.

The rest are probably for steering wheel controls, dimming, etc.

Edited February 10, 201213 yr by stefanhinote

Exactly my first taught, but the blue plug covers both power + fronts. I'm only concerned with the adjacent white plug which handles the rear out. Just want to figure out which y/b/r/w wires represent a positive or negative.