How far to buidl?

[Team808]

DC subs lvl 4's are a nice choice, Dc has great customer service.Also the dc amps are nice, i have 2 teammates that use them, 1 uses the 2k and the other the 5k,So cant go wrong there.Headunits pioneer,alpine ,clarion are 3 of my favorite. as far as highs you will probably wanna listen to some before you buy.If you go to a shop see if they have any installed in a car, listening to them on a sound board isnt the same.Good luck, and show some pics when you get the stuff!

[Team808]

Oh ya, i would do the 6.5's instead of the 6x9's also.

[Nine8SST]

To answer your question, "How far to build".....I say go as big and badass as you financially can, you wont regret it. The only limit I have on my build is my budget, if I had more money I would do more. But, with that being said.....creativity and hard work can make even a "low budget" build shine. Just look around the forum (not SMD specifically) and you will see what I'm talking about....there are people who drop tons of cash into their rides and just throw it together and it looks like shit, and then there are guys who have more time than money who are putting out SOTM worthy builds.

I agree with Sierra....I love my Kenwood HU. But, I just gotta know.....why do you need 4 volt pre outs? Also, for mids and highs I have experience with Fosgate, Infinity Kappa, Polk and Kicker.....I choose Fosgate. I just love the Fosgate sound and always have, and I'm sure part of it is that I grew up on it. However, you may want to rethink the Infinity....they are way too harsh IMO. With that in mind, id money were not a contributing factor I would be running Focal Components.....I heard them once and that was all it took for me to recognize the quality.

Mainstream subs are way over priced for what you get and when compared to several other brands. I didn't even know about DC until I joined SMD and when compared side by side with other brands they just cant be beat in my opinion. I have also heard great things about Sundown, and Skar seems to be making alot of people happy these days.

[ChrisAllen]

To answer your question, "How far to build".....I say go as big and badass as you financially can, you wont regret it. The only limit I have on my build is my budget, if I had more money I would do more. But, with that being said.....creativity and hard work can make even a "low budget" build shine. Just look around the forum (not SMD specifically) and you will see what I'm talking about....there are people who drop tons of cash into their rides and just throw it together and it looks like shit, and then there are guys who have more time than money who are putting out SOTM worthy builds.

I agree with Sierra....I love my Kenwood HU. But, I just gotta know.....why do you need 4 volt pre outs? Also, for mids and highs I have experience with Fosgate, Infinity Kappa, Polk and Kicker.....I choose Fosgate. I just love the Fosgate sound and always have, and I'm sure part of it is that I grew up on it. However, you may want to rethink the Infinity....they are way too harsh IMO. With that in mind, id money were not a contributing factor I would be running Focal Components.....I heard them once and that was all it took for me to recognize the quality.

Mainstream subs are way over priced for what you get and when compared to several other brands. I didn't even know about DC until I joined SMD and when compared side by side with other brands they just cant be beat in my opinion. I have also heard great things about Sundown, and Skar seems to be making alot of people happy these days.

There are several reasons that I want 4 or 5 volt pre-amp outputs. One reason is better sound quality. Another reason is you don't have to turn up the volume up to get the same loudness as compared to 3 volt pre amp outputs or other ones. Also, I don't know which Focals you would buy, but I've heard that Hybrid Audio Technologies is not only cheaper than the focals, but will beat the hell out of them. I am considering the hybrid audio technologies ones actually.

[Nine8SST]

You might wanna do a bit more research on your reasoning for wanting higher voltage outputs.

[ChrisAllen]

You might wanna do a bit more research on your reasoning for wanting higher voltage outputs.

Sorry if I don't know my information, that's what I was told by a guy that has a really big system in his car. Supposedly he hit 150+ with it, but who knows =? Could you give me some information?

[mlstrass]

Crescendo 1000C4 for $199 shipped is hard to beat for a solid 4ch amp. 125x4 @ 4ohm, so plenty of power for the comps you want to run.

Never been impressed by Infinity comps though. Just installed a set of the Pioneer TS 6.5's in my son's car, quite impressed for $115 shipped off amazon...

[Nine8SST]

Both of these articles are from other sites, but they explain things pretty well.

Pre-Amp and output voltage - By Eddie Runner

Pre amp is usually the control center. Your volume control, tone controls, EQ (if any) and source switching is usually at your pre-amp. The Pre-Amp is designed to be a very clean low signal voltage and take care of any signal modifications you might want to make to the signal (music) BEFORE the signal goes to the amplifier.

Pre-amp signal is usually LOW, it was designed to be low so there is less distortion at this stage. Home pre-amps usually operate with about 1 to 1.5 volts of output, the idea was to keep the voltage down as low as possible to keep the distortion down as low as possible in the pre-amp stage and then after the signal leaves the pre-amp we let the amplifier do what it does best.

In car audio we have used this very low level for years with pretty good success. But in many cases in car systems there might be some noise. Some of the car stereo manufacturers have stepped up the output voltage of their headunits in an attempt to help us have a noise free system.

Installers have always found that certain types of noises in a car system can be reduced by turning down the amplifier gain controls. But far too often the customer gets his system fairly noise free but with no gain!! The system just may not play loud like it should if the gain controls are turned down too far. Turn the headunit all the way up and it still wont get loud. This is where the manufacturers come in with the higher level headunits! Now you can turn them higher, even when your gains are very low (and hopefully any bad noises are also very low)...

Some purists find this added amplification (and distortion) on the headunits appalling. But most of us cant really hear the added distortion and find it much better than the noise !!!

Some rookies find the added headunit voltage an advantage cause now they think their amp will play louder! NOT TRUE! The amp will still have its maximum output power and it will not change in most cases of the amps max drive can be achieved. Many rookies compare a 1or 2 volt headunit with a 4 to 8 volt headunit and they only notice that with the higher voltage the system gets loud at 10 (on the volume scale) and you used to have to turn it up to 30..!! Some rookies are fooling themselves into thinking this is GOOD! This is better!! But it may not be.

Ideally, a system has a good swing to the volume control... Too much signal voltage into the amp the system will get loud too soon on the volume swing. Not enough signal voltage to the amp and they system volume control can go all the way up and not get loud like you might like it. Setting the amp gain controls correctly will give you this proper swing!

And the rookies may not know it, but if they set the gain controls correctly with a low signal output headunit and compared it to a high signal output headunit then there would be NO volume difference anywhere in the system volume swing...

But I still hear them say, "WOW, I got a 5 volt headunit!, it sure plays louder!, its worth the money!"

I just shake my head in amazement...

Preamp output voltage by Perry Babin

Preamp Output Voltage

You have probably heard (or read about) people discussing 2 or 4 volt output head units. This section will help you (hopefully) to understand what they're talking about. If you haven't read the 'audio output' or 'head unit' pages, you should go read them now. The 'op-amp' page will also be of interest to those who want to know more about the electronic components.

Regulators:

In virtually all head units, the available voltage is the battery or charging system voltage. The voltage supplied by the charging system is not exactly 'clean'. It has all sorts of spikes and dips from electrical accessories turning on or off (or just from the current they pull). Most head units use op-amps (covered earlier) as buffers on their preamp audio outputs. These op-amps can reject some of the noise from the power supply but not all noise. To get a 'cleaner' power supply, the engineers employ a voltage regulator. This voltage regulator reduces the voltage to approximately 10 volts. The op-amps operate from this regulated voltage. The following diagram shows the 'dirty' voltage from the charging system and the 'clean' regulated voltage. OK, enough about regulators.

Op-amps:

In general, most op-amps cannot drive their outputs all the way to ground or to the regulated voltage. They may not be able to drive their output within 1.7 volts of either. This means that their output signal is limited to the regulated voltage (9 volts) minus 3.4 volts (1.7 * 2) equals 5.6 volts. Now remember that we are talking about peak-peak voltage output. The RMS voltage is only 35% of the peak to peak values. This means that the output from the op-amp will be limited to 1.96 (2) volts.

Rail to Rail Op-amps:

In recent years, the audio manufacturers started using opamps that could swing very close to the full supply voltage. This means that their peak-peak output voltage is very close to 9 volts. This means that their RMS output voltage can be as high as 35% of the regulated voltage. With a regulated voltage of 9 volts, they can get 3.15 volts out. If they increase the regulated voltage to 10.5 volts, they can get close to the claimed 4 volts out without a switching power supply. Some head units will use a second, inverted 4 volt output on the pre-amp output shield (which would otherwise be connected to ground). This will produce a balanced 8 volt output. This configuration is similar to amplifier bridging.

Switching Power Supplies:

A few head units and more than a few signal processors, use a switching power supplies (similar to those used in amplifiers) to get a 30 volt (plus or minus 15 volts) power source. These are getting even more popular in decks that have EL (electro-luminescent) displays. In these devices, the op-amp can swing to within 1.7 volts of the +&-15 volts for a total peak-peak voltage of ~26.6 volts. The RMS output can be as high as 9 volts. You will see this type of output rating on many equalizers and crossovers.

The diagram below shows the relationship between the voltage output levels of each of the types of outputs. The white line would represent the voltage output produced by the op-amp powered by the switching power supply. The green colored waveform, the 4 volt output. The yellow, the 2 volt output.

NOTE:A piece of equipment that has a higher maximum output voltage is not necessarily going to sound better than one which is only capable of 2 volts output. The higher output will allow you to reduce the gains on your amp (or any down line signal processor) which will lower the noise floor of your system. If you are not having trouble with noise (alternator, hiss...), you may not benefit from the extra output voltage. You also need to realize that the voltage may be more than your amplifiers can handle. The extra voltage will not damage the amplifier but if the lowest sensitivity (gain setting) on your amp is 2 volts, and you drive it with anything more than 2 volts, it will cause your amp to clip*.

*This assumes that the gain setting is the voltage that will drive the amp to max power. Some amps are underrated and may have slightly more headroom and therefore will clip at a little higher power.

Output Impedance:

Some head units (or other devices that have an audio output signal) rate the output impedance of their pre-amp lines. These specs will tell you how robust the output signal is. Since all decks have more than a zero output impedance (50-500 ohms) and all other devices have something less than an infinite input impedance (10,000-100,000 ohms), the input circuit will affect the signal from the previous piece of audio equipment. A lower output impedance (50 ohms) will be affected less than one with a higher output impedance (500 ohms). The most common (and least degrading) effect on the signal is the slight reduction in the signal level. This slight reduction is generally never noticed and is completely normal. A bigger problem appears when some piece of equipment does not have a purely resistive input circuit. This is generally from a ultrasonic filter on the input. These will cause the high frequency part of the signal to be attenuated more than the rest of the signal. Equipment with higher output impedances will have more high frequency roll off than those with a lower output impedance.

[ChrisAllen]

Wow, thank you so much for that information. I think I am a bit more confident to look for a good head unit now. I'll talk to a good friend that owns an audio shop.

[ChrisAllen]

So, what pre-amp output voltages should I be looking for? Right now, I'm looking at a 4v headunit, a 2.2v headunit, a 3v head unit, and a 5v head unit. Actually, several of each.