D class amps
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=31134
Printed Date: May 18, 2024 at 7:00 AM
Topic: D class amps
Posted By: 52brandon
Subject: D class amps
Date Posted: April 27, 2004 at 1:50 PM
I am sure this is a common sense question to most of you but bear with me here. How many subs can I hook up to a D class amp? A friend of mine that was an installer at best buy said I could do as many as I want, but I don't believe him. My subs are 4 ohm and 500 watts RMS each. Any amp model/brand suggestions will be appreciated. Thanks
Replies:
Posted By: One_Evil_Necro
Date Posted: April 27, 2004 at 1:56 PM
are your subs DVC? It would also depend on the stability of your amp 1 Ohm, 2 Ohm etc..arg work
Posted By: 52brandon
Date Posted: April 27, 2004 at 2:04 PM
Posted By: mross014
Date Posted: April 27, 2004 at 2:40 PM
If you think about it you can go parallel, then series ,then parallel, then series and repeat indefinately while adding subs, until the amp can't push any more.
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LivnLouder by the paycheck
Posted By: Thack79
Date Posted: April 27, 2004 at 3:30 PM
Dual Voice coil. Like many of the rockford fosgate subs that has two connections
Posted By: 52brandon
Date Posted: April 27, 2004 at 4:24 PM
oh sorry, just was drawing a blank on that one, no they are single voice coil
Posted By: forbidden
Date Posted: April 27, 2004 at 4:59 PM
You can still hook up as many subs as you want actually, I have hooked up no fewer than 36 single 4 ohm sub to Rockfords old Power 150.1 amplifier. The smallest mono amp that they had and it knocked the phone off the wall in the Subway next door. While this did not drive the subs to anywhere near the full capabilities, it was sure impressive. So I'm sorry to say that your friend was right, you can in fact keep hooking sub sup to any amp as long as the load on the amp is within the tolerance of it's design. You owe your friend a beer. As far as properly powering your subs, it is crucial to properly power a sub and match the amp - sub - BOX together with proper use. You need to post more info about your subs, vehicle, cd player, box type etc. Always post the barnd and model # of any equipment used. ------------- Top Secret, I can tell you but then my wife will kill me.
Posted By: 52brandon
Date Posted: April 28, 2004 at 8:43 AM
I am going to be getting a mid 90s cadillac deville, I wrecked my suburban and took my stereo out of it. My subs/box are Audiobahn ABP15, it is a 15" bandpass kit (I may need new subs too because I don't know if they were internally damaged in my accident). I am going to be using a Clarion DVD player for my head unit, the model number is DVS9755z, which brings me to a new question. The head unit uses a 5.1 system for the stereo (2 front, 2 back, 1 sub and 1 middle) and my car has 6 speakers and 2 subs. I am thinking about 2 different ways to hook it up let me know which would be best. 1) hooking up only 4 speakers to the speaker RCAs, and the 2 subs to the middle and sub RCAs, or 2) using 2 y-connectors to split my middle channel into 2 channels and my sub channel into 2 channels (therefore utilizing all of my speakes and subs). Please let me know the positives vs. the negatives, thanks
Posted By: forbidden
Date Posted: April 28, 2004 at 2:56 PM
You have a dobly digital surround sound system by the sounds of it if you go with the Clarion dvd. This means front left (1) front right (2) front center (3) rear left (4) rear right (5) and subs (.1) if you are not going to be putting in a front center channel specifically for surround sound, ignore it. This leaves you with a standard cd player for the sake of arguement. Front stage / rear fill + subs. Are you going to be amplifying all the speakers in the car or using the built in amp in the dvd?
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Top Secret, I can tell you but then my wife will kill me.
Posted By: 52brandon
Date Posted: April 28, 2004 at 3:30 PM
I currently have an MTX thunder 6304 4-channel for my highs/mids and was considering another 2 channel amp for my other 2 speakers. On the dvd player there is only 1 RCA for sub output rather than 2 as on most decks, would a y adapter work for that? I just remembered that there is an RCA output on my amp, so I could use that for my other 2 speakers rather than trying to wire it directly from the deck
Posted By: forbidden
Date Posted: April 28, 2004 at 3:54 PM
You are creating a monster, just because you have extra amps or speakers does not mean that you have to use them. Use the rca y splitter on the sub channel and run it to the sub amp. Use the 4 channel MTX amp for the front and rear speakers. I count mid / highs as one pair of speakers as they generally have a passive crossover that both the mid and tweeter wire into, thus one set of speaker wires from the amp. What speakers exactly do you have and where do you plan on putting them. Your list of equipment seems to grow by the post, post all of your equipment and state whether you have it or are going to be purchasing / replacing it.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: customsuburb
Date Posted: April 28, 2004 at 6:10 PM
forbidden wrote:
You can still hook up as many subs as you want actually, I have hooked up no fewer than 36 single 4 ohm sub to Rockfords old Power 150.1 amplifier. The smallest mono amp that they had and it knocked the phone off the wall in the Subway next door.
Whoaaa! Could you PM me the whole story?
Posted By: forbidden
Date Posted: April 28, 2004 at 7:58 PM
How's about I let it out of my bag of tricks for all to see, it is really quite simple. As long as the amp sees a stable impedence, we can do pretty much anything. Here is how I did this, if I remember right. Take 36 single voice coil 4 ohm subs, I used the basic Rockford punch subs. Take 18 generic ported dual 12" sub boxes. I used the Megahertz CR212P ( a perfect match to the subs) Stack the boxes 6 high and 3 wide. Install all the subs. Take a sheet of 1/2" plywood and anchor the backs of the boxes together (don't want the leaning tower of subwoofers) Wire all boxes in series to 8 ohms each, thus 18 8 ohm loads Think of each stack as two stacks of three 8 ohm subs, parallel wire the three boxes together, each stack of three now should have a reading of 2.67 ohms. Parallel the top stack of three to the bottom stack of three on each stack of 6. Each stack should now have a reading of about 1.145 ohms. Now you should have 3 stacks each with a reading of 1.145 ohms, series wire each stack for a final reading of about 3.345 ohms. I'm going from memory here and this looks pretty close to what I had, can't remember for sure. This setup wails, even though each sub was only seeing about 5 watts, it played well into the 140db range here in the front of the store. No replacement for displacement. And yes indeed it did knock the phone of the wall next door. ------------- Top Secret, I can tell you but then my wife will kill me.
Posted By: customsuburb
Date Posted: April 28, 2004 at 8:09 PM
You had that many subs in stock? Did you have any mids or highs or just the subs?
Posted By: forbidden
Date Posted: April 28, 2004 at 8:24 PM
Yes I specifically made this wall to show the customer what the capabilities of a Rockford mono amp really were. My competition kept telling my customers different so I proved them wrong and let the wall stay for one full year. I like my competition, they send me business. The wall was hooked to the sub out on my Rockford display so yes I could actually listen to this wall as well with a decent set of components.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: stevdart
Date Posted: April 28, 2004 at 8:31 PM
I've read that there is a 3 db gain just by adding the surface area of another subwoofer. If this is true for a situation like this where a relatively small amount of power is used, that's an increase of over 100 decibels. Is this right?
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: forbidden
Date Posted: April 28, 2004 at 8:39 PM
Each time that you double your surface area you gain 3 db, thus 1 - 2 - 4 - 8 - 16 - 32 - 64. You are close but no banana. The same formula applis for power, 50watts - 100 watts = 3db. 100 - 200 watts = another 3 db. 100 - 125 watts = sweet fa.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: stevdart
Date Posted: April 28, 2004 at 8:51 PM
oh.... ok. That was way off. Then the db increase (due to surface area) with the 36 subs amounted to just slightly over 15 decibels.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: 52brandon
Date Posted: April 29, 2004 at 8:17 AM
ok, my entire list of what I have and what I plan to buy: Head Unit: Clarion DVS9755z, Speaker Amp: MTX Thunder 6304, Speakers (need to buy still): planning on Infinity Kappas but still undecided (please let me know other suggestions) the sizes are 5.25 for 2 pairs and 6x9 for 1 pair, My subs are the Audiobahn ABP15(4 ohm, single voicecoil, 500 watts RMS each). I am going to be running these off of a 1/0 gauge power wire into a distribution block that splits it into up to 4 different 4 gauge outputs and all twisted pair RCAs. The things I need to get still and would like to get some suggestions from you people that have more experience than I are: a 2 channel amp for my 6x9s, a Monoblock for my subs, new speakers, a 5 farad cap and speaker wire (probably 14g twisted pair). Thanks a lot for all of your help.
Posted By: 52brandon
Date Posted: April 30, 2004 at 8:43 AM
up
Posted By: forbidden
Date Posted: April 30, 2004 at 1:47 PM
I'll have to get to this when I have a little more time free. When I come in in the mornig, the first thing I do is have my bagel and tea and reply to topics. Some I leave for later as I need time to think them through, some require an extensive amount of thought which must be done when I do not have 4 installs on the go at the same time. Not that I do not want to look after you, just time management here at the store, I must look after my paying customer first, no offence intended. First piece of advice, lose the cap, you do not need it. A cap does not make power, it stores and uses power. You will need something that makes power, in this case a alternator. DO it if you need it, it is still too early to tell but I'm pretty sure that you will need one so start your search for one.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: 52brandon
Date Posted: April 30, 2004 at 3:24 PM
so you are saying rather than a cap, to buy a bigger alternator? Should I get a new battery too? I completely understand that you don't have time for this right now, so when ever you get a chance.... thanks a lot for all of your help
Posted By: chevyman26
Date Posted: May 05, 2004 at 8:30 PM
forbidden wrote:
No replacement for displacement..
------------- You'd better get me out of this lord... or else you'll have me to deal with. -- Hunter S. Thompson "F.A.L.I.L.V."
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