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advice, criticism re my planPrinted From: the12volt.comForum Name: Car Audio Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc. URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=81277 Printed Date: May 12, 2025 at 1:49 PM Topic: advice, criticism re my plan Posted By: antoniob Subject: advice, criticism re my plan Date Posted: August 06, 2006 at 4:45 PM Hello,
I’m in the process of designing and building a new system for my car, and I would very much appreciate it if some of the gurus here would look over my parts and plan and offer their observations, potential gotchas, and criticisms. So first off, here are my parts: Subaru WRX STI 2005 PPI A404.2 (4x50@4Ohm, 4x100@2Ohm, 2x200@4Ohm Bridged) PPI A600.2 (2x150@4Ohm, 2x300@2Ohm, 1x600@4Ohm Bridged) Front: CDT Audio HD-62 180wRMS (https://www.cdtgold.com/braxial_hd62.htm) Sub: CDT Audio SQ-100 500wRMS (URL=https://www.cdtgold.com/subwoofers_sq100.htm) Rear: CDTAudio EF-51NEOX 60wRMS (https://www.cdtaudio.com/slim_neo_systems.htm) Head Unit: RAVDVD1 (5V preout, S/N 70dB, THD <1%) Power cable: Kolossus Kable 1/0 Knukonceptz Ground cable: Kolossus Kable 1/0 Knukonceptz Everything else Knuconceptz – Battery Terminals, Distribution blocks, Ground Blocks, etc PPI FRX-456 Crossover : 4/5/6-way X-over Outputs: 6pr X-over Frequency: 7-46, 20-270, 55-500, 80-1.77k, 80-7.5k Future protection: One thing I want to ensure with my installation and design is futureproofing things so I do not have to do anything twice, or rip things out and re-install. I obviously do not need 0GA wire to use 1000 Watts of amplifiers, however, I only wanted to run power to the trunk once and forever. That said, here are a list of things I plan on adding in the future. Carputer - This will be mounted in the trunk most likely along with the amps. The largest DC-DC power supply I can find is about 220 watts, so when using the system design assistant (https://www.bcae1.com/images/swfs/systemdesignassistant.swf) I just put 220 in for an "amp" in the flash configurator. I have 5 outputs on my distribution block, is there any reason that I cannot mix the outputs between the carputer power supply and the amps? I do not know if this introduces any kind of interference or not? Power Inverter (DC to AC) – I plan on adding at least a 1000 watt power inverter as well. As with the carputer above, does anyone see any issues with grabbing power for the inverter from the same distribution block that I’m running my amps from? Again I put 1000 in for an "amp" in the flash configuration tool. Total result was 2220 watts, so I'm putting in 0 Gauge power wire. Of course, I doubt the computer will be at full blast, the inverter maxed out, and my volume all the way up at the same time, but good to overbuild right? Rear Trunk Battery – I plan on adding a second battery in the trunk at some point, probably a Red Top. (As a side note, it seems in the carputer world these are known as “Tank circuits” however in the car audio world, nobody seems to refer to them with that nomenclature, I wonder why?) So I am not sure how this would hook up or how the system design would look, but I’m just going to leave an extra few feet of my 0 Gauge power wire curled up, as I assume that is what I will connect to the secondary battery when it gets installed. I just do not want to do anything limiting with this initial install. So, thanks for any input anyone has in these areas. Crossovers - Ok, now on to the current sound design considerations. The HD-62s come with passive crossovers, my version is called Satnet-480. Here is how they are described per their website: [quote]Technically speaking, the SatNet crossover design is a fourth order/24dB per octave design supplemented by a series first order/6dB per octave on the front end. The unique combination of the two creates a virtual 10th order, 60dB per octave crossover where the critical crossover point between the mid and tweeter is. The benefits of the design are many. First, the power transition between midrange and tweeter is virtually identical. Phase response problems and polarity shifts are almost entirely eliminated. What you HEAR, is a much more natural sounding component system, as if it were that one perfect speaker.[/quote] As I listed above, I also have a PPI FRX-456 Active Crossover. Can I use both the passive and the active? Is there any use for the active on the front components or should I just go with the passives that came with the setup? I assume I should use the active FRX-456 with a low pass for the subs. The rear fills are full range speakers, down to 55hz anyway. Should I bother with the active crossover on those? It kinda seems like I don’t even need the active crossover except for the sub. Here is what I found so far from the rec.audio.car faq: [quote] Many people find it advantageous to use both active and passive crossovers. Often, a separate amp is dedicated to the subwoofers, to give them as much power as possible. The other amplifier is used to power the mids and tweeters. In this scheme, an active crossover is used to send only the sub-bass frequencies to the sub amp, and the other frequencies to the other amp. The passive crossovers are used to send the correct frequencies to the individual speakers (e.g., mids and tweeters).[/quote] How to wire everything: As far as the best use of my amps, I am not sure. The tweeter is 4 Ohms, and the 6.5” woofer is 4 Ohms, but since the amp is only connected to the crossover what does the amp see? I don’t see any specs regarding that on CDT Audio’s web site. I’m assuming it’s still 4 Ohms for now. It seems the best thing is to bridge my A404 into 200x2 and give each front channel 200 Watts. The speakers are rated for 180, so that is fairly close. Obviously the A600 would run the sub. It is 600 bridged and the sub is 500 watts RMS. So, I guess my real question is, how should I power the rear fills, which are rated at 60 RMS? It seems the easy solution is to just purchase another amp, probaly an A300.2 which is 75x2@4ohms. I also just realized I have an old Alpine V12 MRV-T501, which is 75 x 2 @4ohms@14.4v or 50x2@4@12v. I could also use that until I pick up an A300, if I in fact cannot wire things up nicely with just the two PPIs that I have already. Cooling (with water): I plan to have an enclosed box in the trunk holding the amps and computer, so I imagine it will get pretty hot in there. I will mount an amp rack behind the rear seat, but so that it looks more like a false front….I do not want anyone to be able to tell I have amps in my trunk, nor do I want to lose any space I do not have to lose. I have seen the PPI water cooling attachments on ebay before, but, I doubt they were terribly sophisticated back in 1996 besides being hard to find. I have this idea that one could take a high performance water cooling system (such as a Danger Den) and use it to cool the PPI amps, as well as the carpc when it is installed. The overclocking world has some nice water cooling setups now that it’s so common to do, but I sure have not seen many in the car audio world. So, fire away? Thanks any advice! Replies: Posted By: KarTuneMan Date Posted: August 06, 2006 at 5:44 PM How much weight are you planning to load into that 4 wheeled rocket ship....or is it NOT an issue?
Posted By: antoniob Date Posted: August 06, 2006 at 6:44 PM KarTuneMan wrote: It is not much of an issue, as I'm attempting to design the amp rack to be removable, but also completely unhidden and very hard to remove without knowing how to do so. To make it easy to remove I have bought or plan to buy the following items: I've purchased some 16 pin Molex connectors to which I will attach the the various speaker wires so I can unplug all speakers from the amp rack with one plug. I don't have a good quick disconnect RCA solution yet, but pulling them out of the amps is probably not a big deal, there are only a few. The power is only 1 wire, so that's not too bad. The only power quick disconnects I've seen were only for 4 Gauge wire, and cost 60 dollars. Ouch. For a water cooling line quick disconnect I was thinking of using hydraulic quick disconnects like we use on tractors and air tools. The sub I plan on sticking in the tirewell in the floor in a fiberglass enclosure that can be removed as well, and hopefully also maintain the spare tire. This sub might be too deep for that, though, I am not sure. So, to answer your question, yes weight does matter a lot on track days, but hopefully I will be able to easily remove everything. and like they say, the easiest way to go faster is to mod the driver, not the car. (ie, lose some weight!) Posted By: stevdart Date Posted: August 06, 2006 at 10:22 PM Here are some sources you can study. This is a forum search for "crossover". The following are a sampling of some of those threads. You can also do a search for "EQ" or other topics. https://www.the12volt.com/installbay/forum_posts.asp?tid=77065&KW=crossover Note particularly DYohn's input on questions regarding SQ setups. There are references to EQs, passive and active crossovers, and general setup info in the above threads. The following site is great for info on passive and active crossovers: https://sound.westhost.com/biamp-vs-passive.htm I suggest you should get most of the basic stuff out of the way so that you can ask questions on one particular or another. You may not get a whole lot of response to such a long list of issues. ------------- 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: August 07, 2006 at 1:00 AM Consider Rob's school of widsom as sometimes it has aided many a person. I am a big time fan of 5 channel amplifiers in moderate systems. Your system lends itself to this perfectly. The Eclipse XA5000 is a full range class D ICEpower amp rated at 50wx4 and 450w x 1. It is probably a better match of power and use of power at the same time. Heat is nowhere near as much as a factor nor the power draw on the electrical system vs. the class AB amps you are considering. Nect up, the saving of real estate in the trunk, the extra expense of wire and it's weight. You eliminate another possible source of a ground loop at the same time. The more I use this amp, 3 in the last week, the more I enjoy what it does for my customers to build a great system around.
------------- Top Secret, I can tell you but then my wife will kill me. Posted By: antoniob Date Posted: August 13, 2006 at 4:54 AM stevdart wrote: While I do thank you for responding, I have to say I am quite dismayed at the response. I spent quite some time crafting my post so that it would convey, without question, that I am not a rude internet n00b who showed up without bothering to search, and without investing lots of my time before asking somebody else to spend their time. I made a long post with most of the relevant information that anybody might ask so that nobody would need to waste their time looking up the specs of any part that I have, and so that nobody has to waste their time asking me questions when I could have politely included all relevant information in the first place. I have read through thousands of posts, and I've searched my ass off on the12volt, bcae1.com, termpro, elitecaraudio, diymobileaudio, avsforums, carsound, sounddomain.com, mobileaudio.com, rec.car.sound, mp3car.com, carputer.org, zedaudio.com, etc. I was looking for a critique of the setup as a whole, and of the individual components as they relate to each other. While I am well aware of the general benefits and drawbacks of passive and active crossovers, I am still unfamiliar with the specific quality or characteristics of the crossovers that CDT uses. For example, they claim they are "phase perfect". Is that true? I don't know, if it is, that is one less reason to go fully active. It seems to be better than average for a passive, although that has been hard to determine without actually asking someone. This passive is 24dB, the active I have is 12dB. Is that a point in the passive's favor? Hence me asking those kinds of questions. stevdart wrote: I only asked 4 or 5 questions. I'll make the same post for you, succinctly.
Posted By: antoniob Date Posted: August 13, 2006 at 5:25 AM forbidden wrote: Thanks for your help, and ideas. I have read his website, most of it anyway. He reminds me of Richard Clark. In a "The Emporer has no clothes" kind of way. forbidden wrote: That would be very nice, to only need 1 amp. However, are you sure that this will take full advantage of the speakers I have? The sub is rated 4 Ohm, 500RMS. The XA5000 only puts out 350 Watts at 4Ohms. And the components are rated 180RMS, while the XA5000 can only put out 50x4 @ 4Ohms. Wouldn't this amp be vastly undpowering the speakers? I honestly would much rather use an amp like the one you suggested. What I really need is an 8 channel amp, that will do 200x2, 75x2, 50x2, and 500x1 bridged. I have never found such a thing, though. Thanks again! Posted By: forbidden Date Posted: August 13, 2006 at 12:06 PM As far as the speakers "needing" that much power, simply untrue. Your speedometer says your car do 240 km/h but it is just as happy driving at 50 km/h. Having played with more and more and more of these new amplifiers every day (another 5 channel and 4 channel yesterday), I am more than convinced that they are what you should consider. If you really have a hangup for power on the front speakers, consider then the XA4000 (125w x 4 ) and the XA1000 (450w x 1). The amps sit real nice side by side and look like one big "cool" (as in ICEpower cool) amplifier. While the power is more than you need for the rears, gain setting of course can help you overcome the power obstacles. The XA5000 is one stellar platform for balanced output all the way around. The XA4000 and the XA1000 is also a balanced platform, not too much in the front, not too much in the sub, just right in the rear. ------------- Top Secret, I can tell you but then my wife will kill me. |
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