New car hi-fi build!

[Marco]

Whoa, someone's been a busy boy!

Did you build the sub-box to the correct internal volume for the driver? That's absolutely critical. A fair bit of maths is needed to get that right

Marco.

[fatmarley]

Ported is critical but you do have some leeway with sealed. A smaller sealed box takes more power to achieve the same volume as a larger one and it raises box q, so you can end up with a hump in the frequency response. But because I'm crossing at such a low frequency, the hump wont matter so much.

Recommended internal volume is 28ltr, mines 22ltr. Worse thing is to go too big imo, the cone just flops around and sounds loose (but obviously that's not the case if your driver has stiff suspension).

[Marco]

No worries... You'll just need to see how it sounds when you try it with some bass-heavy music, at volume. Is the sub going in the boot?

How much power's going to the sub?

Marco.

[fatmarley]

Sub is going behind the passenger seat.

I've got the same JBL mono amp as you, so 350w into 4ohm. If I feel it lacks depth, I'll buy the Eminence Lab12C that I mentioned earlier in the thread.

[fatmarley]

Fitted everything in, including a new pair of JBL GTO 609C components and - Oh dear! With the gain on the amp set to maximum there was hardly any extra bass. A select few tracks were loads better but most weren't that impressive. Feeling very dissapointed I Googled the problem and found out that Alpine head units have a subwoofer level control that adjust the pre amp output voltage. You have to set it to maximum before adjusting the gain (lots of people seem to have been cought out by this one).

How does it sound? It's like a disco in my car Bass is tight and hits hard, mids seeme pretty good to me. Treble is mostly good but sometimes gets a little bright or busy. One tweeter does measure with a big dip in the middle of the response (around 7khz IIRC). Maybe I should message the seller, or JBL UK?

I'm waiting for some foam rings to put around the outside of the midbass drivers to seal them against the door panel. Apparently it improves midbass and possibly midrange. I'll take some measurements after to compare.

Measured the thiele/small parameters of the Standard Toyota midbass driver. It's got an incredibly high QES (3.6) & QTS (2.6) caused by the smallest magnet i've ever seen on a speaker. It's 3db less sensitive than the 92.5db 2.83v/mtr JBL 609C.

Not sure if I should upgrade the head unit or not. If I do i'll probably get this - Alpine CDE-178BT

[Marco]

Good stuff, mate. Glad you got it sounding good in the end!

You're not still using the Toyota mid/bass drivers, are you? Because the JBLs shouldn't sound "bright or busy", although that could be the influence of the head unit. Make sure you familiarise yourself properly with all the setting controls, to optimise the sound as best as possible. Also play around with the positioning of your sub.

Btw, if you're thinking of upgrading your head unit, Kenwood do the perfect one at that price level, as it a very healthy output voltage, which gives the whole playback system/amps plenty of 'headroom'. My installer sells them, just need to check the model number, and I'll let you know, plus he'd do you a good deal

Marco.

[struth]

The toyota sound system gets a bad name, although i think mine sounds pretty decent for a standard equipment...They do a jbl upgrade but i didnt bother.

[fatmarley]

Good stuff, mate. Glad you got it sounding good in the end!

You're not still using the Toyota mid/bass drivers, are you? Because the JBLs shouldn't sound "bright or busy", although that could be the influence of the head unit. Make sure you familiarise yourself properly with all the setting controls, to optimise the sound as best as possible. Also play around with the positioning of your sub.

Btw, if you're thinking of upgrading your head unit, Kenwood do the perfect one at that price level, as it a very healthy output voltage, which gives the whole playback system/amps plenty of 'headroom'. My installer sells them, just need to check the model number, and I'll let you know, plus he'd do you a good deal

Marco.

I've still got the standard Toyota speakers in the rear but they are playing at a 3db lower level because of the sensitivity difference over the JBL, and they are high passed at 80Hz. I haven't removed the door panel yet but I think they are a full range driver because there is no sign of a tweeter anywhere. Reading online and going by my old car hifi days, most people say you shouldn't use rear fill unless it's bandpassed and delayed. I think i'll try fading to the front on my head unit to see what the JBLs sound like on there own. The old tweeters sounded similar (with and without an amp) so maybe it is the head unit causing it.

I'd rather stick with a Alpine head unit because the amp I use only works with Alpine (KTP-445A). Thanks for the offer though

[fatmarley]

The toyota sound system gets a bad name, although i think mine sounds pretty decent for a standard equipment...They do a jbl upgrade but i didnt bother.

I suppose it depends on what year/model Toyota you have. My old Avensis was much better than my Auris.

[struth]

I suppose it depends on what year/model Toyota you have. My old Avensis was much better than my Auris.

mine is new(chr) but to me sounds fine. goes loud enough for me and doesnt do anything nasty. not saying its great by fancy stereo levels, but, to me its a car stereo.
think astral make the head unit. china i believe