Mug

After five years of not having a real sub in my TL, I finally decided to research the topic. It has increased my desire to upgrade all the speakers. Because I'm not that crazy about audio, I don't want to get too wild. I like deep, sealed bass. I hate the thought that the highs will sound less powerful if I just upgrade to one sealed 12" sub.

So, I decided to upgrade the whole thing (except the head unit). Maybe a five channel amp to run the four corners and the sub. I've search and haven't found any clear reasons for not running speaker level inputs to the amp.

Why are so many people running LOCs and equalizers in their TLs? Is this just for increased control or do we need them because of our stock head units?

I hate cars

You can run speaker level to the amp if the amp accepts them. Some do, some don't. Coming off of the stock amp to an aftermarket amp, the signal is going to be pretty strong. I had to run a LOC off of the stock sub signal to knock it down a little, it was just too much for my amp.

The number one issue with going from the stock amp to an aftermarket amp is you're amplifying a dirty signal. You will have a little hiss no matter what you do because you're amplifying a signal that has a hiss in it.

With that said, going after the stock amp is very straight forward and easy and it sounds pretty good as long as you don't crank the gains up too much on the aftermarket amp. Otherwise you will have a hiss especially at low volumes.

Straight from the head unit, pre-amp has the potential for much cleaner sound but also the potential for more problems if not done right. You can end up with ignition and alternator noise. Doing it this way requires a good ground and following all install rules like keeping power away from signal wires and such. You will likely have to use a line driver (the opposite of a LOC) to boost the signal since it's only .8V best case scenario. Install the line driver as close to the hu as possible for the greatest noise reduction. I ran mine post amp for a couple years and I was satisfied with it. I now run it pre-amp because my higher end speakers really picked up the hiss a lot more and after a little troubleshooting it's virtually noise free even with a ton of power going to it.

It won't hurt to try post amp first with an amp that will accept the high level inputs and skip the LOC altogether if you're able to. If you're not satisfied, it won't take much to go pre-amp. Be careful because I started off like you and ran a couple subs and an amp with everything else stock for a couple years. Then I started upgrading to the point I became one of those "weirdos" that spends nearly $10k on a system. One thing I've learned is loud is pretty cheap. Sound quality is expensive. A system with both great sound quality and SPL is even more expensive.

As for the processors, they give you much more control over the sound and they can give you a good sound stage. For example, mine sounds like there's an actual stage above the dash up high but right around the hood where all sound comes from. On a good recording you can hear where the singer is, where certain instruments are, etc. You can no longer hear individual speakers and locate the source of the sound. Once you get used to it, it's hard to go back. With that said I wish I had never tried it. You can get great sound for a reasonable price by shopping around and keeping it simple. To get that extra 10-20% is where costs start climbing rapidly.

There are some great 5 channel amps out there. I run a JL HD900/5. It's a powerhouse and fits under the seats. Not cheap but it has a lot of features that I need plus it's a class D so it's efficient (less heat, less power consumption). There's also the JL XD series and PPI makes a great 5 channel that's cheap. I run a pair of 15s infinite baffle so they only take up a couple inches of trunk space. I still have 90% or more of my trunk available. Bigger is usually better with subs whether you want sound quality or loudness. They will have less distortion, more efficient, and dig deeper with less power but space is the downside unless you go IB. I chose this setup for sound quality because they're always in the most linear range since they barely move most of the time.

Trunk Monkey

iTrader: (1)

^ I was about to type that exact same thing. Touche

Mug

Thank you so much. That helps me out a lot. I'll try the post amp first and hope for the best. Thanks for spending the time writing that up.

stevemk07

I think I am gonna tryost amp as well. I soent some time holding a zoom h2 microphone where my head would be and it is very flat except there are two flat levels. Bass below 260hz or so is flat down to 80hz and past 260 it dips down until 500hz (will have to check the difference) then relatively smooth all the way up as far as around 8, 9k then slopes down. turning treble up 1 helps level it out to about 12k-15k. So I am thinking lowered crossover point and more active and pleasant tweeter would make the biggest improvement.

eggyhustles

what the hell is deep sealed bass?

Trunk Monkey

iTrader: (1)

something you only get from JL Audio subs

stevemk07

oh yeah, not much response above 10k in this car. would that be result of the amp or tweeters?

I hate cars

The stock mids roll off up top naturally, no filter. The tweeter takes over between 8-10khz. There might be a gap in there between where the mid rolls off and the tweeter picks up. The 4-10k range is where things can get harsh, maybe Acura played it safe?

jda123

I can get over 20K with the stock HU and my aftermarket stuff. It is kind of immaterial what it is if you are going to replace it all - it is probably a combo of the stock amp and speakers. Even with very detailed speakers, I probably would have not noticed anything over 14-15K if it was not there unless I was really paying attention.

stevemk07

Since i first heard the system on the test drive i knew there were no upper range frequencies.

stevemk07

So anyone get good high frequency response when getting their signal AFTER the stock amp?

Mug

I'll let you know in a few weeks. I just ordered my stuff and plan to use the post amp signal.

I hate cars

Yep. I ended up with the full range.

Mug

Crap. Now I'm seeing all of this dynamat in the DIY threads. That stuff is expensive! I should at least do the back deck and truck lid right? 12" sealed sub is going to rattle the crap out of that trunk.

stevemk07

i havent noticed much rattling from the trunk. just the license plate. easy fix to put something there to stop those rattles.

Good to know about getting signal after stock amp. I guess the stock tweeters are the problem there.

Has anyone else enjoyed the results of turning the bass down to around -5? i get the flattest resonse this way with treble at +1. Sounds like better speakers in there.

I hate cars

It depends on a lot of factors. With a pair of 12W6s in a sealed box facing the rear of the car the deck and trunk lid would rattle. With the same subs in a much louder 4th order bandpass with the port firing through the skipass, no rattles because no bass was in the trunk.

With the infinite baffle setup, I had rattles since the trunk is the box and I have a pair of fairly high excursion 15s. Most of the rattles can be taken care of by stuffing a piece of foam or cardboard between the rear glass and the rear deck. I would start there and see how it sounds.

Make sure the license plate is secured will all 4 screws. Remove the license plate frame if you can. This is free and will take care of the majority of the rattles from the trunk. If you still have rattles, remove the carpet and start adding damping material.

My preference is Second Skin for damping and sound blocking but there are plenty of good companies out there. Some ripoff places as well. One of the most important areas to deaden is the doors and door skins. I would try the free stuff to stop the rear deck and trunk rattling first but I would deaden the doors for sure.

Mug

So with the Infinity Kappa Five, it says max input is 6 volts, and sensitivity is 200mV. Is the sensitivity the lowest voltage it will accept with satisfactory results, or is that something different? Also, if it does accept 0.2 volts input, does that mean I can use the pre-amp input from the TL?

Trunk Monkey

iTrader: (1)

The gain on the amp is for matching voltages of your input signal. Many people use it as a volume knob and then wonder why their speakers distort and sound like crap. With that pre-amp signal at around .5v, your amp gains will be damn near maxed out. I'd look into a line driver if going pre-amp.

Mug

Thanks trunk monkey, I thought it was around 1 volt so I thought I could go pre amp. I want the ability to adjust bass and treble from the HU anyway. Thanks for the info.

jda123

I use the pre-amp signals without any kind of a line driver. Gains modestly set in the middle somewhere. A lot of this depends on the amp and what kind of signal it will accept. I tested mine out at around .9 with an o'scope and I went with it. I have no idea what a DMM would read, but it would not be accurate on a audio signal.

Mug

What about the input post amp, is that more than 6 volts?

jda123

I never tested it. The post-amp signal is cut and it is full of noise, so I never cared.

stevemk07

while i have to wait to do my upgrading im having some second thoughts about it. My system sounds good with bass cut to -4. vocals are clear and focused, drums sound punchy, guitars have that bite back, etc. but knowing the system misses half the hz is a bit of a problem for me. Maybe just some nice tweeters would fix that. Anyone know of some sweet tweeters for liitle?

Trunk Monkey

iTrader: (1)

^ The tweeters only cover from about 10kHz and up. Just keep saving until you can afford a complete set and/or separates and go with an amp that can go active.

stevemk07

mine only covers about 8 to 11k. The sound is very good despite that because most of the meat in music is below that point. I was thinking about the focal 165vb with an eq of some sort because i am the type to get one. i calibrate my tvs stereos guitars amps etc till perfect. drives gf crazy. keeps me sane possibly

I hate cars

I'm not sure why yours is only measuring to 11k. It should go higher even with stock tweeters. The crossover frequency from the mids is right around there, are you sure the stock tweeters are working?

For best sq, you want a system that covers 20hz-20khz. Yes, covering 20hz is important if you want to accurately reproduce music and it gives a ton of impact and sense of energy when it can go down that low. While most people can't hear 20khz, it's been proven important that the system be capable of it.

However, flat according to an RTA is not what you want. I've never met a person who likes the way a system sounds when it's RTA'd flat.

stevemk07

ya according to rta drops right off. maybe something is wrong with mine. Anyway my syb runs pretty flat to 25 hz where the subsonic filter is set at. Sounds good. tweeters is problem. when turn treble up i get a big spike that increases at around 10k. still sounds ok tho.

jda123

You guys sure about 10K? I remember that they play before 5K, but perhaps I am misremembering... I am getting old.

If you are happy, then just leave it alone for a while. Contentment is an expensive lesson wrought with lots of wasted hours - be one of the few that don't learn it first hand, or learn it young.

Trunk Monkey

iTrader: (1)

I'm just judging by the cap that's on the stock tweeter. (3.3uF cap)

Mug

Some pics. Not too happy with the quality of the sub. The outward facing seal was falling off right out of the box. The sub and box are easy to replace if I'm not happy with the sound. It's an Infinity Reference 4ohm DVC.

jda123

If you have the extra wire, put that thing in the rear corner and point it towards the other side. See how you like that.

jda123

That cap will limit based on resistance. Ohm load is nominal and changes at frequency. At most higher level frequencies, tweeters can be well above 12 ohms (or often times higher). I would guess that this is crossing from 3000-3600hz. Test tones would be the best way to verify if anybody still has the stock stuff in their car.

stevemk07

i ended up leaving centre speaker off and prefer this way. stage is wider and less confusing. i have found only one dvda disc in my area and nothing is really put in that format anymore. was interested in the new pink floyd dvda but you need to buy the $100 box set to get it. oh well...

ihc, thanks for pointing out that rta does not need to be flat. i also lowered subsonic filter to 15hz and it did make a noticable difference.

Trunk Monkey

iTrader: (1)

Look up "house curve" and you'll find lots of info about a non-flat EQ curve...or lack there of a curve.

stevemk07

Thanks I will look into these curves. I remember mention about sound curves in my reading but sorta ignored it. I thought it wasn't relevant to my purpose but I guess it is. Seems confusing at the moment.

Mug

I was planning on moving it around once I had it all hooked up to get the best sound. Not sure if it will look that great in the corner (box is too big). Has the corner been known to be the best location for a sub?

MOS805

I used pre amp signal with an Infinity Kappa 5 for my front components, it was enough signal for the amp but I did run into problems of noise in the signal that I was never fully able to get rid of. Kappa 5 will also take the speaker inputs post amp, I used that for my sub signal and it worked perfectly. But you do have to solder on RCA's to the input wires because even though the amp takes speaker level inputs it has to still be in the form of an RCA connection.

eggyhustles

weak motor

small sealed box

...equals poor response.

I hate cars

Agreed. I think a large box will work wonders for cheap or small motor subs. Look at the success some people are having from running $40 15" Pyle subs IB.