Audio FAQ, Part 2 - LONG - Compiled posts

[Sandi_k]

Audio FAQ, Part 2 - Compiled posts from Sept. 2005 to Aug 31, 2006
Compiled by Sandi_k

Part 1 here: Audio FAQ, Part 1 - LONG - compiled posts on speakers, installation, amps, etc.

********** Begin part 2 here **************

Sensitivity ratings of speakers
Replaced front and rear speaker, but rear speakers distort when turned up loud

The diamond speakers say 100hz-20,000hz. Should I get a bass blocker for 100Hz and below? Crutchfield says 600hz and below for 3 1/2 speakers, but the diamonds go lower than normal speakers

Brandon4589

Cos you'll notice the cute little highpass filter soldered on to the connector on the stock speaker in the rear? That prevents low frequencies from getting through and wrecking the speaker. Run to radio shack and grab one, and solder it inline, I'd say 500Hz to 1kHz for those little guys. Cheers.

B!tchmonkey

Well just because they can reproduce @ 100 Hz doesn't mean they can do it well. My little headphones here can do 40 Hz but only at about 1 inch from my ears. The 3-1/2 might do well at 5 inches away from your head in a nice quiet room but ya really have to make speakers work in a vehicle. I would say a 500Hz (or 600 like crutchfield says) is ideal for a 3-1/2 at full power. And last I heard, diamond audio stuff kinda sux, but I have never even heard one so I digress. You'll never get quality sound without an AMP and the CORRECT crossovers for each speaker.

I went with Boston 3-1/2's in the dash and rear pillars with and threw an inline 500Hz hgihpass filter on those…

B!tchmonkey

Speaker Installs in C Pillar:


Install pics of sub, amps, speakers in C pillar:
Complete Audio/Video Upgrade...

FJRod

Ruebarb did this too – he has pics of the finished product posted.


Amp Installs

I have an amp under the drivers seat, fits with ease. It does not block the air vent, it has feet and actually sits over the air vent without interrupting the air flow. Dimensions are:

» 13-1/4"W x 2-3/8"H x 9-9/16"D


I don't even have rear speakers, but had them wire me up for them should I want to add later. On the amp I have the sub on the rear and the other (rear) speaker wires on the front (for future use) and all the other speakers are running off the head unit. I am a former DJ who just wanted a good, clean sound -- but this system has MUCH more than that.

LAFJGirl


Both of my amplifiers are mounted under the seats. I cut out a piece of 1/2" MDF and siliconed it to the floor under the mat on each side. There is plenty of room under the seats and no holes in the undercarriage. We do this often on the rear wall of trucks too. Once set up, the panel will never come loose. You can get it out at a later date if needed.

Audiox


Re: Amp install questions... 2 or 4 channel?

Do you have a sub, do you want one in the near future?

If so, purchase a 4 channel. Use the front two channels to power the front speakers (components) then bridge the rears to drive your sub.

I wouldn't recommend using the rear speakers at all. If you do though, use the head unit power to power them.

If you're not going to get a sub, go with a 2 channel amp and use the head unit t power the rears (again, if so desired).

Vik

Re: Adding a sub and amp to the stock FJ stereo?

The stock systems don't have rca outputs. Just buy a line output converter if you just want to add an amp. They're easy to hook up, just tap into the speaker wires for either the front or back depending on what you want to amp.

Twofoolish2b

Amp Install

I mounted it under the passenger seat. In an attempt to not block the heat duct I cut, painted black, and mounted one 1/2" MDF spacer board on each side of the heater duct so the amp bridges over it.

Alpine MRV-345 has no gain adjustment for any of the channels.

Ropedrag


Re: Power for under-seat amp?
ChrisInSeattle previously said:

I want to install an amp under my passenger side seat. What's the best/preferred way of running power to that location? I guess you want to keep the power in away from the speaker outs, which would seem to preclude running both down the center console. But I don't really see where I could run the cable on the other side of the seat. I am probably going to have this professionally installed, but I want to know a little bit about it before I do down there.

Also, on a similar note, how do you remove the passenger seat?

There are 4 14mm bolts holding the seats down. You will also need to disconnect the wiring harness underneath the seat. The seats come out extremely easy, but the big problem is the fact there are rear vents underneath the seats. You either have to remove them and tape off the vent so no air comes out or mount the amp on top of the vent. When I installed my nav system, I ran wires down the center console and under the door sill. It's pretty straight forward. The rubber flooring is not glued down, so it lifts easy to run wires. Good luck!


(If a 4 channel amp were added):

You would have 1 speaker per channel if you are using 4 ohm speakers and trying to keep everything 4 ohms. If the amp is capable you could go 1 2 ohm speaker per channel or use two 4 ohms on 1 channel *I think*. If nothing else this is real close. This is sort of just a bump for you again to get some of the audio experts to hopefully take notice. I have been trying to get back into adding a stereo for the first time in about 10 years so I am a little dusty. Right now I'm building a box for a sub and just put in the Memphis 6x9" in the doors and 3.5" in the dash. I like them (although I never could get any feedback on them) They are budget compared to what others have talked about. It was $110 for both.

Rhettdog


Impedance

Re: 6 speakers replaced, great difference
I replaced the dash and rear speakers with Blaupunkt 3.5" coaxials and put 7" aluminum cone woofers in the doors (8"drivers would also fit just fine). I had to fab some standoffs from 2 layers of 3/4 ply to properly mount the door speakers. There was also some trimming required on the inside of the door panels, but it looks stock from the users side...

I also added some crossover components to dash and door sets to ensure that each driver is working in its best range. You can get parts at www.partsexpress.com if you want. I've dealt with them for years, they have some nice stuff.

Properly matching impedance of the new drivers to the old ensures plenty of volume without an extra amp. It'll work fine.

Bartt


Re: 4 ohms/8 ohms

After a little more research, it seems that the front dash speaker (8 ohm) and the 6x9 door speaker (4 ohm) are wired in parallel on the two front channels. This would give you and impedance of 2.66 ohms. Because it is a parallel system, the affect of adding a 4 ohm speaker is less. By adding a 4 ohm dash speaker with a 4 ohm door speaker the total is 2 ohms, thus the difference is .66 ohms. I retract my previous statement that this would overdrive the head unit. Slight difference, but not enough for concern.

The same seems to hold true for the rear. The ceiling exciters are 4 ohm and the rear pillar speakers are 8 ohm. Replacing the rear pillar speakers with 4 ohm would yield the same effect. The reason toyota has done it this way, is to limit the amount of power that goes to the small 2.6" high range speakers in the dash and in the rear pillar. A 8 ohm speaker will receive a little less than half of the wattage that a 4 ohm speaker would in a parallel wired system (the 4 ohm speaker has less resistance).

Long story short, 4 ohm full range speakers can be added to the dash and pillar without ill affect. Although, they will play a little louder than the 2.6" 8 ohm speaker do now.

GSGMac

General Comments that Might Be Useful


8” Rounds vs. 6x9” speakers

Not without reading the spec sheets on both. The 6x9 will put out more bass. More cone area. I prefer the sound of 6.5" midbass drivers, and let the sub take care of the bottom end. But speakers and sound reproduction is a very individual thing. What sounds great to one person may sound like crap to someone else. If possible, listen before you buy. The Quarts are nice. I have a set of Q series 6.5" components that are amazing!

Audiox


Re: Speakers for a Jazz Fan

Personally, I'd avoid a metal tweeter for jazz. Piano highs, etc can be a bit much when the volume is turned up. But you may enjoy the bright sound... and many speakers allow you to lower the tweeter volume...

For deck power alone you need to find a more sensitive speaker to take advantage of the lower power the deck pumps out vs and amp.

Rps 23


Re: Speaker Recs only?

If you want to keep the stock deck, but replace the speakers make sure you get ones that are very sensitive (ie higher db rating the better). More sensitive speaks will work better with less power. Higher sensitivity will significantly reduce the issue FlyBiz had

Infinity Kappas are really sensitive, so may be a good choice. They have a rating of 95db for the 6x9s vs 89-92ish for other "major" brands or even the infinity refs. 3db may not seem like a lot when you look at the #s, but it really is a ton in volume/performance with a low power system. Kappas are 95db for the 3.5s too... If I was going with stock deck and no amp these would probably be my choice, plus they are pretty cheap online!

Rps_23

Re: BAHHHH Infinity Kappa Speakers Help! UPDATE:

Ok, I've gotten around my little hiccup and if anyone else got the Infinity 3.5's with crossovers by accident never fear. There is plenty of room in the dash to mount them. I actually attached mine with two plastic zip ties around a small vent tube for air on each side which is accessible via the speaker openings.. There is plenty of room for the speaker and crossover unit.

Silverdusk


The rockford 3.5's are great choice for the 4 surrounds, I put Pioneers in the doors, due to their 28 Hz response, my low end is actually better than stock. I found them online after a few hour searching for the right response 93 db and frequency range 28Hz to 33k Hz. None of the Rockford 6x9's could match this combo. I then searched by part number and found them at Walmart online and they were available a mile from my house for $75, good deal..........The sound is incredible without amps, very clear and not muddy.

AttillaHunley


The other thing that I have advocated before is adding some crossover elements (1mH coil for each woofer, and an 80uF polyester cap for each tweeter), otherwise the highs will dominate.

Bartt


Re: Speaker Recommendations only?
The difference is night and day, and I have not added an amp yet. What I find really amazing is the quality of the head unit for an OEM part. With all the right drivers I can max it out and there is virtually no distortion. I thought that it might clip at higher volumes, but it doesn't.

Overall I only spent about $110 on all the drivers including the dual voice coil driver in the rear door and the 7 inch drivers in the doors, and it sounds damn good. Everyone who's heard it agrees. :-)

I've been designing and building audio systems for many years so I know a little about this.

Bartt