12v Nick

Can't believe I didn't see this thread until now. Must be too busy assembling tweeters...

It's definitely arguable that the source is the most important element in an audio system. Since everything cascades down from there, the better your source material, the better the end result. That said, just because it's the most important doesn't mean that the rest of the system isn't. Every component in the chain has the opportunity to foul up the final response.

A head unit with a poor DAC can step on the resolution and dynamic range of your source media, a poor quality amplifier can distort that sound, and low quality speakers can skew the reproduction making a non-linear response. Even non-electrical components like the acoustic environment factor into the results.

My advice for anyone with a critical ear looking at a new car purchase is to explore your options for a local high-end audio shop to retrofit an aftermarket system into a "base stereo" optioned car. Now, geographically speaking, not everyone will have this opportunity due to the decreasing amount of aftermarket shops that have enough knowledge and skill to do that job right — that doesn't mean you shouldn't at least do some local searching before the purchase.

Heck, with a new purchase you could even have your car delivered to another dealer that had a local outfit they worked with like that.

squid42

Well, I still think the focus on speakers is correct.

The source - well your favorite music you have in whatever format you have it. You can choose, unless you exclusively like music that is originally 1990s style radio compressed (audio compression, in this case multi-band compression). You can play that in several places and presumably you already have a place where you like this music that is not your car (headphone, home stereo etc).

Amps. It possible now to make Class D amplifiers that perform well enough to not make a different with almost all speaker systems. You need some engineering, but the resulting construction can be made cheaply. You buy those amps from manufacturers who did the engineering (presumably), you don't start over. Speaker cables - well you either have to be outright broken or very, very thin to make an audible difference.

Speakers - well now it gets tricky. In the amp world your car manufacturer charges you $900-$1500 for a bunch of $10 amps and $10 speakers (subwoofers not included). But - they can buy a reasonable amp for $10 because of the progress made in Class-D amps. They cannot buy reasonable speakers for $10 a pop, and that is where the bottleneck is.


I would also like to remind people that some systems (and I think Porsche's Bose is included) use fiberoptic signal cables between crossovers and amps, and some of the amps might be physically a distance away from the head unit. If that is the case you get into a headache when you want to put in better gear because you won't have a copper wire there.

skynet

Easiest way to get great audio regardless of system is to simply play great recordings when in your car.

I don't even care if they are 128bps mp3s, these recordings will sound awesome.

some examples, try one of these in your car and report back:

Alison Krauss New Favorite
Dire Straits Brothers in Arms
Muddy waters Folk Singer
Norah Jones Come Away with Me
Michael Jackson Thriller
Daft Punk Random Access Memories
Beach Boys Pet Sounds

Dan Nagy

I drove a MGB that I purchased in Seattle to Washington DC. The ride in a Porsche would be a helluva better trip!

Thanks for working on the tweeters. I am looking forward to receiving mine.

cmjohnson

Speakers are first, quality of the source is as important. There is little difference in wire and cable. Note I said LITTLE difference, not NO difference.

Any wire has definable electrical characteristics, inductance, capacitance, and resistance. These are the components of an RLC network which by definition is a filter. There is no question that any cable acts as a filter for the signal passing through it. Knowing the values of the cable and the output impedance of the source and the input impedance of the sink, the precise response modification curve over a defined frequency range can be exactly calculated.

I do not question that wire and cable can make some difference, what I question is whether or not the actual cost to engineer and make "better" cables is in any way related to the price on the box that the customer pays for it.

"High End" cables are pure profiteering. If you were to know the secrets of how they make cable, the cable they use that they sell to you for a hundred bucks a foot plus another hundred bucks per termination probably comes from Alpha or Belden Wire and Cable and costs the brand name manufacturer under a dollar a foot at the receiving department dock.

squid42

We don't disagree on anything real here, just that the low impedance output of almost everything in Hifi or professional audio makes the LPF that the electrical properties of the cable (combined with stages "reachable" without impedance change) irrelevant. You need very bad cables to have enough capacitance to damage a low-impedance line output, not to speak of a solid-state power amp output. And unshielded speaker cable builds up practically no capacitance.

Exceptions are phono needles, passive guitar pickups and the like, those are high impedance units that are vulnerable to capacitance load and input impedance of the next stage, and the electrical properties of the cable combine with those of the magnetic coils.

Of course if you try hard enough you can find a bad enough cable. In practice I have seen a lot more problems with cables that kinda worked but were mostly broken and changed the sound that way.

In cars people go to length with either optical (signal) cables or heavy shielding because of the electric motors/generators which can cause audible electrical interference. However, such cables can lower the original quality of the audio (not counting interference).

cmjohnson

There is no disagreement from me. I know that source components can sound different, amplifiers can sound different, and speakers can sound different, but if cables make a significant change to sound quality then something is WRONG. With one caveat: In the case of amplifiers with a low impedance output, cable choice can demonstrably change the system response characteristics.

There are some guitar amplifiers that have multiple impedance transformer taps. While not recommended, choosing one tap and then another to plug your speaker cabinet into can have a very obvious effect on the overall sound of the amp.


An impedance of 1 ohm on the part of a speaker cable at a defined frequency is not a big deal unless it's a significant percentage of the output impedance of the amplifier. Like a tube amplifier, for example. Tube amps are more sensitive to cable changes than solid state.

It's not magic, it's electronics math. RLC and impedance of source, sink, and cable are all definable, their response modifications can be predicted, this can all be modelled in computer software, or even figured out with a calculator, and in fact nobody has yet invented the perfect current source or the perfect speaker or the perfect cable.

wisky

All you guys are scaring me. I just ordered a 17 C2S with the base stereo, how bad could it be?!

cmjohnson

Objectively, it sounds good. Subjectively, I hate Bose and love really GOOD sound and the highest priority option on my list if it's not going to be a track car would be to upgrade to the Burmester sound system. Some companies and some people, you hate them so much that you don't like anything they do ON PRINCIPLE. Bose is like that for me.

I simply hate the company and their advertising and marketing practices and their excessive pricing for the level of performance you end up getting. But their products are slickly packaged and easy to use.

12v Nick

Bottom line is that EVERY component in a good sound system is important. You can argue at the priority order, but the truth is that one bad element breaks the entire system – regardless of it's position in the stream.

If you enjoy music, you should be scared. Haven't heard the base stereo in the 991.2, but if it's anything like the past few generations it's going to be pretty lousy.

Hurricane

That's a long drive!

squid42

Those guitar amplifiers are tube amps, which have multiple taps into the output transformer (and which sound a bit different depending on how much of the output transformer you use). Tube power amps also have a fundamental property that makes them sound different than solid state, and that is that their output impedance doesn't brake the speaker as much as solid state amps when the signal suddenly goes flat. The tube amps let the speaker continue to oscillate quite a bit more. That loosens up the sound and makes it appear substantially less "stiff" which is an advantage in many applications, although strictly speaking it changes the sound from the original more than solid state.

Having said that, tube amps are not quite a realistic reference for car stereo.

For anything power amp you find in a stock car you will have a hard time making a sound difference with a speaker cable. The speaker cables in the car are also short. Of course a broken cable will do.

911boy

Thats what I have as well. Through ipod it sounds ok but radio isnt great. Sirius sounds brutal but same with most systems I would imagine. Having said that, the car is very loud so it doesnt bother me. Really don't know what they could do considering all the wind, tire and engine noise. Listening to radio can't be made much/any better i don't imagine.

911seeker

"Hard time" in this context is a great understatement... there will NEVER be ANY audible difference that a normal human being can perceive by changing cables in a car audio set up unless one (the pre existing or the new) is broken. Forget about your math...


Same applies to amps IF they are reasonably powerful to drive the specific speakers installed.


And same will apply to CD player, digital radio player, Sirius XM player, MP3 player.


Changes in those elements might make sense for other reasons, NOT sound quality.


You want to improve the system: change acoustics (not possible in a car), change speakers and/or equalize.


Best

12v Nick

Respectfully, and with a good deal of experience in this area, I'm going to disagree with some of that. Speakers are definitely the biggest rocks in the road on the way to quality sound, but the other components do make audible differences....

You're right about cables for the most part, but we have to consider what a signal cable's job is in a car audio application — (1) not degrade the audio signal and (2) not introduce any noise. The latter is the most important since the audible degradation of signal through analog cables in a car is only discernible in the worst cables made(chickity-chinese-garbage). Rejecting noise however, is an audible difference, and a cable with higher noise rejection will yield better dynamic range in an audio system. Is it dramatic? — no... Is is discernible to the average listener? — probably not.... but it does make a difference in high-end performance audio.

Amps not making a difference? I really with you were close enough to stop by and listen, and if you're ever in Portland, please do. My inclination is that you haven't head a difference in amplifiers yet so you might have a false sense of what changes they make in a system. Topology has a lot to do with this, and the industry is always advancing, but there are definitely major audible differences. Class-A/B amplifiers are much more warm and detailed than Class-D amplifiers. We literally just built a system in a BMW that we weren't in love with the end result — amplifier swap made all the difference.

The Source player is also a key element – it's converting the digital signal to an analog stream. That's an important job! It doesn't matter how bad *** your kitchen sink's faucet is — if the water treatment plant doesn't get it right, you're still going to end up with brown water.

Also, changing the acoustics of a car can easily be done. Well, let me rephrase.. It's a simply procedure for someone with the knowledge on how to strategically apply acoustic damping material to treat the interior of the car, thus creating a better and more optimal environment for the audio system.

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