Amplifiers and speakers, Understanding the numbers?

greatwhite · 03-02-2008, 12:07 PM

Hi all,

I "sort of get" some of the numbers a specs on amplifiers and speakers. BUt I lack the knowledge to understand how they all work together or what constitutes a "good" piece of equipment.

Does anyone know of a decent "layman's terms" site that explains the meanings of the numbers and how they relate to real world use?

Or how to properly select your components so that they work well together to give a decent SQ setup?

I've looked at the FAQ's, and unless I missed something, they were of little use with regards to this.

For example, here's the spec list for an amp I'm using now (I know it's not a high end one, I've only got so much money to through around right now):

Pioneer GM 6200F

CEA 2006 Specifications
Output Power (4 Ohm, <=1% THD) 60 Watts x 4
Output Power (4 Ohm Bridged, <=1% THD) 150 Watts x 2
Output Power (2 Ohm, <=1% THD) 75 Watts x 4
Signal to Noise (1 Watt into 4 Ohms) 80dBA
Dynamic Power (4 Ohm) 60W

Peak Music Power 600 Watts
Number of Channels 4
Load Impedance Capability 2~8 Ohm (Stereo)
4~8 Ohm (Bridged)
Continuous Power (4 ohm) 60W x 4
Continuous Power (2 ohm) 75W x 4
Continuous Power Bridged (4 ohm) 150W x 2
Frequency Response 10Hz ~ 50kHz
Total Harmonic Distortion 0.010%
Signal-to-Noise Ratio >95dB
Dimensions 11-13/16" x 2-3/8" x 13-1/4"
Features
Bridgeable
Channel # Capability 2/3/4
PWM Regulated MOSFET Power Supply
Compression-Type Speaker Terminals
Balanced Isolator Input Circuit
RCA Inputs 4 Channel
RCA Outputs (Pass Thru)
Speaker Level Input 4 Channel
Input Level Control Hi-Volt (400mV ~ 6.5v)
Built-in Crossover LPF/HPF (Front/Rear Independent)
Crossover Frequency Range 80Hz, -12dB/Oct.

Other than knowing that the RMS wattage is the only real number for the power (seems most people agree peak is for marketing purposes) I don't really understand the numbers.

Here's a pair of components I have:

MB Quart dsg 216

TECHNICAL DATA
Power Handling: 50 - 120 W
Frequency Response: 45 - 32.000 Hz
Impedance: 4 Ohms
Crossover Frequency: 5.200 Hz
Sensitivity: 87 dB (1W/1m)

FEATURES
0.75“ (19 mm) tweeters with titanium dome and neodymium magnet system in plastic housing
Woofers with two-piece plastic chassis, red polypropylene cone with edge wound voice coils

Other than trying to match the rms ratings, I'm kinda lost with regards to how the amps and speakers should be selected for each other (altough I do understand the amp should be powerful enough to prevent clipping and adjusted properly).

Oh, in case soemone wants to know, I'm running and audigy 4 with kx drivers (still trying to figure that out well enough) and the aformetioned 6.5's and a single 12" sub. No other processesing of the signal is done other than what comes out of the "as downloaded" kxdriver.

Thanks from someone who wants SQ but doesn't have a lot of cash to spend on it.............

greatwhite · 03-02-2008, 12:29 PM

Hmm.

This was somewhat useful:

http://www.rayfes.com/caraudio/ampspec.php

This was helpful also:

http://www.rayfes.com/caraudio/power.php

scott_fx · 03-02-2008, 06:00 PM

those article sounded pretty good, i just quickly skimmed over them though; are you in the process of purchasing new equipment? or just want to learn? if you're going to be getting new equipment and have the drive (it seems like you are proactive anyways), you should consider going 'active'. an active system drops the passive crossovers usually associated with component speakers and instead uses a processor in line before the amp to route signals to the appropriate speakers (kx project should be able to do this) The downside... more tuning needed, and you'll need more chans of amplification upside... more tuning needed (with the benefit of better sq), tuning dialied in based on your car and cost of speakers. (you can spend 1/4 of the amount on raw drivers then a component system with the same sound quality)

this is also a helpful link if you'r going that route:
http://www.diymobileaudio.com/forum/showthread.php?t=31

another thing that that article didnt go into is 'headroom' it brushed apon it with thd ratings but it didn't go into the benefits of getting 100 watt amp vs. 50 watt amp. first you'd think that it'd just be louder, that is true.. yes but the other benefit is when playing at the same volume, the 100 watt amp won't be taxed as much and give you a cleaner signal. the important thing is to set your gains correctly. Think of it this way, you have a 100 hp car and a 200 hp car. both driving at 65 mph... which one is less stessed?

scott_fx · 03-02-2008, 06:05 PM

oh.. and if you go active you can spend less then $150 bucks and have an amazing two way setup that will sound a lot better then passive systems costing many times as much. In my dailly driver i'm going with a two way setup with some phaze audio mw-64's that i picked up for $75 bucks (new old stock) and its in the air right now but probably a seas tweeter ~$25 each. That $125 system will probably beat anything you could find at cc or bb

greatwhite · 03-02-2008, 06:07 PM

Right now I'm just looking to learn.

Been fooling around with audio for some time now, but I'd say I've probably been making the classic mistakes everyone makes of throwing parts together. You know, Buy it, bolt it up and wonder why doesn't it sound good?

Also, budget has dictated lower end components for me so far, so I need to upgrade incrementally for now.

I will probably experiment with what I've got for now (finances dictate that currently) and see how much I can tune out of it. Maybe I'll learn a bi tin the process.

I understand the very basics of setting an amps gain, but that's about it.

Like I said, looking for links that will educate in layman's terms right now. I'm (perhaps) slighty advanced past that point, but only slightly............still Googling...........

Cheers

greatwhite · 03-02-2008, 06:13 PM

Quote: Originally Posted by scott_fx

oh.. and if you go active you can spend less then $150 bucks and have an amazing two way setup that will sound a lot better then passive systems costing many times as much. In my dailly driver i'm going with a two way setup with some phaze audio mw-64's that i picked up for $75 bucks (new old stock) and its in the air right now but probably a seas tweeter ~$25 each. That $125 system will probably beat anything you could find at cc or bb

Now you have my attention...................

Preparing to Google with the words "active" included...................

scott_fx · 03-02-2008, 06:26 PM

just go to that link i sent you and search through that forum.. specially the tutorials section. you can get some very high quality dayton speakers from parts express and be a very happy camper. check out www.zaphaudio.com as well. he has a tweeter mismash and a 7/8" driver comparo that will help you a lot as well.

Look at the Dayton RS180 and Seas CA18RNX for high-quality mids. If 7" is too big, look at the Dayton RS150, the Tangband W5-704S or the Seas CA15RLY

the rs180 is $31 bucks at parts express and the seas neo's are about the same... that setup would be great and cost less then one of the tweeters in my corvette :dumby:

greatwhite · 03-02-2008, 06:29 PM

Quote: Originally Posted by scott_fx

just go to that link i sent you and search through that forum.. specially the tutorials section. you can get some very high quality dayton speakers from parts express and be a very happy camper. check out www.zaphaudio.com as well. he has a tweeter mismash and a 7/8" driver comparo that will help you a lot as well

Thanks, got them both open in another "tab" already.

Reading...................

scott_fx · 03-02-2008, 06:32 PM

http://www.partsexpress.com/pe/showd...number=295-364

i try to always buy from p.e. if possible. they ahve outstanding customer service

Woofnstuff · 03-02-2008, 07:47 PM

with the KX simple is better when making your own DSP.
ive got 5 KX setups now and they have enabled me to do things that would have cost a heap load more for next to nothing

gimme a yell if you get stuck on KX

greatwhite · 03-02-2008, 08:17 PM

Quote: Originally Posted by Woofnstuff

with the KX simple is better when making your own DSP.
ive got 5 KX setups now and they have enabled me to do things that would have cost a heap load more for next to nothing

gimme a yell if you get stuck on KX

Heck yeah.

I'm using the kxdriver as delivered right now. Still reading on that one too. I'm actually a little bit scared to mess with making my own dsp yet, not sure if I'd bugger it up and not be able to go back to stock.

I'm just looking for front 6.5 componets and a sub right now. I might be looking for 5.1 in the future. I have to say though, your post on listening to music and someone else watching a dvd was intriguing...........

I've read the how to's, saved a couple and may take the plunge soon in making my own "little boxes and lines".

Guess my biggest question is not routing the sound through the dsp, it's whether or not I need to add effects, mixers, etc or if the chip will do it all as delivered.

Biggest problem I have with the kx project right now is that I can only play with it in the car and it's currently -11 C here.............

scott_fx · 03-02-2008, 08:53 PM

just an update, the northcreek tweeter from zaph's site says it was discontinued but they have 200 pairs left

Woofnstuff · 03-02-2008, 09:10 PM

this is my KX setup i use for my application.. i wanted 4 stereo outputs...

if you bugger the KX setup just right click in the dsp windows somewhere and "reinitialize DSP" that puts it back to factory

scott_fx · 03-03-2008, 06:34 PM

just read about this sub which looks really promissing in a ported box or even a smallish sealed box:
http://www.partsexpress.com/pe/showd...number=297-460

ronjon228 · 03-03-2008, 08:02 PM

Well I took a quick skim over those links and just had a few questions/comments to make to sum up my experience with car audio equipment and tuning.

Always, always remember KISS (Keep it simple stupid). Too many people go with all kinds of EQ's, Crossovers, Amps, Channels, etc. that absolutely murder the source to the point that it's already mucked up beyond comprehension. Here's a few good rules of thumb to go by...

-Always tune with our EQ's flat (only use the EQ after for MINOR adjustments +/-2db or so)
-Never cross over a signal more than once (ie running low pass out of head unit/pc and then having low pass filter on @ the amp = bad)
-Only go active if you have SQL experience and a good ear (also SQL equipment REALLY helps)
-Tune to what sounds good to YOU (this really is the most important)

If you follow those rules, you should be ok. Basically the less you alter your source, the better the end result is going to be. If you have to change your EQ settings, cross over settings, or gains out of spec, it means your hardware isn't made for what you're trying to do. Therefore at this point it becomes highly beneficial to purchase hardware suited to your application/preference. Then you can use the hardware as your base tune and fine tune with your EQ's, cross overs, gains, etc. In the case of signal processing, less is always more.

When purchasing various equipment there are important factors to consider. The following generally apply.

-Signal to Noise Ratio or SNR (the higher the better, especially important for amps)
-THD (lower is better)
-Frequency Response (Hz range)
-RMS power (peak power is useless)
-Ohms

When picking up amps or speakers remember that the above is important in COMBINATION.

First, decide whether you want to go active or passive. This will influence all of the purchases hence forth. If you're going active, do your homework and be prepared for some serious tuning. In the end, any finely tuned active system will sound better than a comparable passive system. However this tuning takes more experience and equipment than passive route. Just keep this in mind.

Next pick out your speakers based on your preference. If you like soft highs, get silk dome tweeters. If not, grab metal dome tweeters. If you like more heavy mid-range get mid-bass drivers that have lower Hz response. Etc, etc. Also, make sure to note the impedance (2ohm, 4ohm, etc.) of all the speakers you'll be using. This is important for matching up the proper amp.

Once you've got your speakers picked out, get an amp to match them. First and foremost, make sure your amp can operate at the proper impedance (ohms) of the speaker(s) you've selected. If your amp can't match the impedance of speakers being used it will render the amp useless. You can cause MAJOR damage to the amp or speakers by running incorrect impedance levels (especially to the amp). Check the x-over's on the amp vs. the Hz response of the speakers to make sure you can match them up. If you're going active, it really doesn't matter, but you get my point. Also, get an amp that pushes 25-33% more RMS (very important to use RMS on all components) than the speakers are "rated" at. This way you can keep the gains down and the signal clean. Remember that any amp produces more noise and higher Db levels, meaning that even an amp with a killer SNR will sound terrible if you're using 100% of the wattage it can produce. This is why using that 25-33% buffer zone is important.

Once you've got the speakers and an amp selected, the rest is up to you. Tune the system to your liking and DON'T mess with it after. One of the worst things you can do is try to fiddle with it too much or change/add/remove too many components. This will throw all the work you've done out the window, remember KISS again.