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Car audio amp/power question


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14 replies to this topic

#1 of 15 Neil Joseph

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Posted June 07 2004 - 04:39 PM

I just replaced the deck in one of my cars. It can do 45W x 4. It only currently has 2 front speakers and nothing else. I want to add two rear speakers and then later add an amp and woofer box. As the car is a little older, I absolutely don't want to spend a bunch of money on this upgrade.

My question is this... Would it be wise for me to use the deck to power the 4 main speakers (2 front and 2 rear) and use the amp (a cheaper mono amp) solely to power the woofer? Will I have to be careful not to get too powerful an amp for this woofer and if I did, would the woofer overpower and drown out the other speakers or would my bass adjustment be enough to reduce the woofer in comparison to the other speakers?

Ideally I would like to simply run the 4 speakers off my existing deck and save on the amp.
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#2 of 15 DarrenHo

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Posted June 07 2004 - 06:09 PM

you absolutly can do this. powder the four full range speakers with the deck. get an amp and how every many subs you want. you can always match the level of the speakers and sub from either the deck or the gain on the sub amp. i'm assuming you have preamp outputs on the deck. this is the way i originally ran the system in my car. i did get a 4 chanel amp for the front speakers eventually.

#3 of 15 DonnyD

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Posted June 08 2004 - 12:14 AM

Neil,
Sounds like a plan to me...although there may be a thing or two to keep in mind.
First, while the deck may be rated at 45x4, it probably will be more like 18-20 wrms which still should give you better than stock according to the speakers you have.
It would be a plus to you if you can actually use some type of simple crossover so that your deck amp is driving your sats in the 80hz and up range and allow a small amp/sub config to get only the 80hz and below. Kinda like Home Theater.. right?

This would utiize the deck amp and the sq would improve due to the deck amp not having to reproduce low end.

If your deck does not have a crossover built in, then you could use some simple bass blockers to limit what goes to the sats. Then the amp you purchase for the sub should have a built in crossover so you can pick its transfer also....

Hey, I'm pretty sure that car audio can get about as complex as HT!!!! As a matter of fact, I have an 8 year old deck that allows me to select slopes of 12,18,24 db per front, rear and sub,..variable crossover points for each,..eq for each speaker,..along with a bunch of other stuff. So when you get started in this, the nature of your HT system may be your driving force.....BUT.. car audio is SO MUCH cheaper to get that monster sound....Have fun and enjoy!
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#4 of 15 Brad_Harper

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Posted June 09 2004 - 07:06 AM

You can certianly power your 4 speakers off your deck. The actually RMS power coming out of a 45x4 deck is probably only around 12 watts (not a lot). Just be sure to buy really efficient speakers (over 90dB) and you won't have a problem. When you do add a sub just adjust that gain on the sub amp as to not drown out the other speakers.

#5 of 15 David.G

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Posted June 13 2004 - 06:50 PM

ok, well good ideas but little off. First a 45x4 from most major manufacters does 20-25RMS. Only Clarion goes below 20RMS. Secondly, they can power certain speakers but it depends. Since it sounds like you're on a budget than most of the speakers you buy will be ok. I won't expect too much SQ even if the HU is decent. And yes, car audio is as complex as HT and maybe even more due to the constraints. If you look at my HU, its DSP, 2 chip parametric EQ(mid and high EQ), time alignment with db level, 8v preouts, low,low/mid,mid/high/high crossover each with slopes between 6-24db, phase, and the usual graphic EQ. i won't try to compare HT to car audio cause they're different environments and needs. Also even if you buy efficient speakers you need to buy speakers that don't need a huge RMS rating to power them. You'll be looking at the lower end models. You'll get better results if you buy a 4ch amp use the first 2 channels for the front speakers and bridge the 3and 4th for a sub. It works pretty good. Also you can adjust the gain of a sub at the amp for level or at the HU. HU does more sound level, the amp does more the frequencies it receives. If i were you i'd get a K series Elemental Design flat cone model for 65-105$. They're in the overstock sections since they're making V.2 for their sub lines.
David is the car audio guy, Jason is the home audio so if you see a post in car audio thats David, if in Home thats more than likely Jason. Confusing isn't it!!! Also i hope i am allowed to put my sounddomain down on my equipment page. Its car audio but you guys might enjoy it.

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#6 of 15 Neil Joseph

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Posted June 19 2004 - 08:24 PM

I have decided to go slowly on this project. Currently I have very poor quality 4.5" front speakers. I think I will begin things by replacing them and also installing two rear speakers of decent quality at the same time. Phase 2 will comprise of the amp/sub upgrade.
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#7 of 15 VinhT

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Posted June 20 2004 - 01:33 PM

Quote:
First a 45x4 from most major manufacters does 20-25RMS. Only Clarion goes below 20RMS.
Oh dear, more misinformation, David? I think you will find that most head units, regardless of their peak rating, will offer 12 to 13 watts RMS. Even your beloved brand, Eclipse, openly admits to a mere 13W RMS despite 50W peak claims. As for the statement concerning Clarion, when you make such a generalization, it may help to offer some sort of objective data to back it up. Of course, this is all irrelevant, since your head unit will power your coaxial speakers just fine, Neil.

Quote:
Also even if you buy efficient speakers you need to buy speakers that don't need a huge RMS rating to power them.
There you go again, holding steadfast to the notion that amplification and speaker RMS ratings must be matched. This is simply not true.

Consider for a moment how sensitive car audio speakers are (usually due to minimalistic passive crossovers). Most are in the 90dB at one watt range. Now, consider that sensitivity ratings are usually derived at one meter. When you put the speakers in a car, cabin gain comes into effect. Furthermore, you are sitting ridiculously close to the speakers! As a result, car audio speakers can get damagingly loud with very little power. (Note that subs are not mentioned here.)

I think you might be misunderstanding what RMS stands for. It has nothing to do with power requirement.

Quote:
And yes, car audio is as complex as HT and maybe even more due to the constraints. If you look at my HU, its DSP, 2 chip parametric EQ(mid and high EQ), time alignment with db level, 8v preouts, low,low/mid,mid/high/high crossover each with slopes between 6-24db, phase, and the usual graphic EQ.
Level of complexity is the same, car audio is just more difficult due to the unforgiving nature of the car environment. Home theater receivers can perform the same functions as your head unit. There is not as much flexibility needed in the home environment when it comes to crossovers. As for graphic/parametric EQ, I use one in my car (AudioControl DQT), and it is a dangerous tool without measurement capability (which is probably why auto-EQ functions in receivers are so popular).
Vinh Tran

#8 of 15 Neil Joseph

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Posted June 19 2004 - 08:24 PM

I have decided to go slowly on this project. Currently I have very poor quality 4.5" front speakers. I think I will begin things by replacing them and also installing two rear speakers of decent quality at the same time. Phase 2 will comprise of the amp/sub upgrade.
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#9 of 15 VinhT

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Posted June 20 2004 - 01:33 PM

Quote:
First a 45x4 from most major manufacters does 20-25RMS. Only Clarion goes below 20RMS.
Oh dear, more misinformation, David? I think you will find that most head units, regardless of their peak rating, will offer 12 to 13 watts RMS. Even your beloved brand, Eclipse, openly admits to a mere 13W RMS despite 50W peak claims. As for the statement concerning Clarion, when you make such a generalization, it may help to offer some sort of objective data to back it up. Of course, this is all irrelevant, since your head unit will power your coaxial speakers just fine, Neil.

Quote:
Also even if you buy efficient speakers you need to buy speakers that don't need a huge RMS rating to power them.
There you go again, holding steadfast to the notion that amplification and speaker RMS ratings must be matched. This is simply not true.

Consider for a moment how sensitive car audio speakers are (usually due to minimalistic passive crossovers). Most are in the 90dB at one watt range. Now, consider that sensitivity ratings are usually derived at one meter. When you put the speakers in a car, cabin gain comes into effect. Furthermore, you are sitting ridiculously close to the speakers! As a result, car audio speakers can get damagingly loud with very little power. (Note that subs are not mentioned here.)

I think you might be misunderstanding what RMS stands for. It has nothing to do with power requirement.

Quote:
And yes, car audio is as complex as HT and maybe even more due to the constraints. If you look at my HU, its DSP, 2 chip parametric EQ(mid and high EQ), time alignment with db level, 8v preouts, low,low/mid,mid/high/high crossover each with slopes between 6-24db, phase, and the usual graphic EQ.
Level of complexity is the same, car audio is just more difficult due to the unforgiving nature of the car environment. Home theater receivers can perform the same functions as your head unit. There is not as much flexibility needed in the home environment when it comes to crossovers. As for graphic/parametric EQ, I use one in my car (AudioControl DQT), and it is a dangerous tool without measurement capability (which is probably why auto-EQ functions in receivers are so popular).
Vinh Tran

#10 of 15 Neil Joseph

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Posted June 24 2004 - 12:02 PM

Update:

I bought and installed 2 rear speakers, Alpine 5.25". Then I replaced the 2 factory fronts with Alpine 4.25". Finally, I got the amp (Solid Audio) installed today plus a 10" box and all I can say is it is much better than the lone two factory 4.25" speakers that I had initially. Posted Image
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#11 of 15 Neil Joseph

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Posted June 24 2004 - 12:02 PM

Update:

I bought and installed 2 rear speakers, Alpine 5.25". Then I replaced the 2 factory fronts with Alpine 4.25". Finally, I got the amp (Solid Audio) installed today plus a 10" box and all I can say is it is much better than the lone two factory 4.25" speakers that I had initially. Posted Image
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#12 of 15 David.G

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Posted June 30 2004 - 06:01 AM

actually the low end Eclipse(3454) was benched at 15-17 and the 8443 was benched at 19-20s. The Pioneer IMO has the best ratings with a consistent 20. Companies always underrate or overrate their products so even if they do print out something its not always accurate. From my experience the Sony amps ( i had the GTX460, 4x25 or something like that) give about the same output as my HU. I was severly disappointed with the Sony amp and sold it, but it disappointed me so much because there was no difference in output as if i had run it off the HU. And also i'm quite aware of RMS but for me i'm not as "get by with just enough" mentality towards car audio. I'm not saying you guys don't like good sound, but from a lot of the posts here, you guys don't want huge performance from your stuff like i do. To get the best performance from the speaker w/o having to crank up the volume or turn up the gains, you should try to run a speaker close to the recommended RMS rating. I always try to get within 20RMS for most speakers and the subs i suggest w/in 100RMS for a sub, but there are exceptions to this like my EDO12.14.
As far as complexity, i'm not syaing that home audio isn't technological like car audio, but IMO car audio is much harder and unforgiving as HT. The different materials in the cars change the environment and is much harder to tune. i think thats why most car people like front stage only and not 5.1 or a full stereo setup, cause they're too lazy to calibrate the speakers correctly. But anyways as long a your happy with the results thats all that matters.
David is the car audio guy, Jason is the home audio so if you see a post in car audio thats David, if in Home thats more than likely Jason. Confusing isn't it!!! Also i hope i am allowed to put my sounddomain down on my equipment page. Its car audio but you guys might enjoy it.

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#13 of 15 David.G

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Posted June 30 2004 - 06:02 AM

also how do you like the DQT? I'm not sure if i want to get one of the Audicontrols EQ or get a DSP processor or just get a Digital amp.
David is the car audio guy, Jason is the home audio so if you see a post in car audio thats David, if in Home thats more than likely Jason. Confusing isn't it!!! Also i hope i am allowed to put my sounddomain down on my equipment page. Its car audio but you guys might enjoy it.

http://members.sou...

#14 of 15 VinhT

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Posted July 01 2004 - 03:12 AM

The AudioControl DQT is a fine piece of equipment. Unfortunately, it's not fulfilling, because after you work your magic with the front speakers, you want to do the same with the rear speakers (if you happen to turn on the rear speakers for guests). While a DQT is adequate for a two-seater, I would definitely recommend the DQS (six-channel)for sedans to prevent upgraditis later on.

Also, lately I've been wanting to check out Eclipse head units, since you keep pushing them. Posted Image Sadly, Tweeter in my area has recently dropped Eclipse. I was interested in the 8454, but had doubts about the global EQ. Since there doesn't seem to be any other Eclipse dealers in my area, I won't be able to check them out. What impressed me most about their head units is I noticed that the volume of each channel can be adjusted while in the time correction menu. This is an important feature found in home theater receivers, and I have not seen it in other head units. The balance control is a substitute I suppose, but a bit imprecise for my tastes. I have always wondered how effective time correction can really be when there is still left-side bias due to sound level difference between the two sides.
Vinh Tran

#15 of 15 David.G

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Posted July 01 2004 - 06:37 AM

you'll love the 8454. I don't like to push products unless i've used them and was impressed with them. It does have the ability to adj the DB level for 6 ch. in the Time alignment section. 0 to -6db for high left and right, mid left and right, and low left and right. I don't really use mine for the lows but mid and highs i use it alot and it makes a difference especially at high volumes. The PEQ( pro mode) is also a killer EQ. its basically like two parametric EQs in one. You won't find an EQ like this in any HU i've seen so far. Its 10-bands but each band is adjustable in frequency, so its not like the other EQs where you just adjust the gain on preset frequencies. This one you pick the frequencies, pick the gain, and the slope. You seem like a SQ nut so you'll be happy with it. Its very precise since its digital processing and the 24DACs are very nice for CDs.

I haven't gone to an active EQ yet b/c of the Eclipse but i'm adding more in my car so i'm looking at an active crossover or just upgrading the amps to either digital amps or get TRUTECHNOLOGIES amps. Which reminds me i have a post for you techheads here.

Also back to the original post,how do you like your speakers and setup?
David is the car audio guy, Jason is the home audio so if you see a post in car audio thats David, if in Home thats more than likely Jason. Confusing isn't it!!! Also i hope i am allowed to put my sounddomain down on my equipment page. Its car audio but you guys might enjoy it.

http://members.sou...


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