ok, this is gonna involve over 240 measurements with my DMM, so at least read the bullsh*t that comes before it so it makes sense and so i dont take wrong measurements, use incorrect equations, etc.
http://i39.photobucket.com/albums/e164/fcelau1/part1ofchart.jpg
take a look at this so you see what im talking about, its the first of several pages of charts...
first off, since i joined these boards i have been given a sh*tload of badly needed advice and have been offered many suggestions which proved correct. this 'test' is also one of them.
hopefully, this will help people with pioneer HU's in general, and i know it will help if you also have the 7800 (or the 9800). its about time i was of some use to somebody, as opposed to me asking me people back in the day (march) if a 5 channel would be good to add a sub to a stock system. as you can tell by my equipment in my sig., ive come a long way.
i got my pioneer deh-p7800mp and installed it myself a few weeks ago. i have made some progress tuning my system, getting my levels matched and tuning my EQ band, but I am still learning a lot about my HU every day.
since i have retuned my system about seven times in the last 2 weeks with varying degrees of success, I figure a good place to start would be to figure out the optimum volume on my HU in terms of unclipped preamp voltage.
Since boosting EQ levels and using other sound processing tools will increase the power the HU is asked to produce, I decided to do 2 tests. I will be doing (thanks thcn) a measurement at each HU volume at both 50 Hz, 0 dB ref., and 50 Hz, -3 dB ref. I will then graph the diff bw [log(0 dB) – log(-3 dB) @ each HU volume level.
According to THCN, the diff. bw the two values will be somewhat constant, until the HU begins to clip and the values given by this equation will then become much smaller.
However, this is not the most practical way of doing things, since I use a great deal of the sound processing capabilities the HU has to offer and this will make the HU clip much earlier.
Don’t know if this will make any impact on tuning, but I will add this disclaimer:
Less than a year ago, I had no idea about any of this sh*t. Until a few weeks ago, my HU had only Bass & Treble.
Now I have a 13 Band EQ that I am dedicating a lot of time to learning to use, but I still have a long way to go.
However, because I have received a sh*t load of advice and support and these forums, and because I have little in the way of expertise to give back, I will make sure that these measurements and the resulting analysis are as accurate as within my means. I am in my 3rd year of law school, so I can certainly handle this!!
My equipment for this test is pretty solid:
1. Tsunami x15-17 RCA’s for the morel comps in the front. Rockford Fosgate piece of sh*t RCAs for the sub. Therefore, any across the board diff in results bw the readings taken from the front output RCAs and the sub output RCAs will be understandable.
2. Goldseries Shielded Audio Y-Cable ($13.99, see link below) that I will take great care when splicing so as to wire it up to my DMM. I didn’t want to just touch the leads to the RCA tips to get the results bc it could be difficult to maintain a direct connection, it would get to be a pain in the *** since I am making hundreds of measurements with the DMM, and also, some preamps can be shorted out if u touch the tips of the DMM to the RCA cable in the wrong fashion. (there was a brief, but terrifying post on carstereos.org I read).
3. Craftsman MS8200T Digital Multimeter ($60 @ sears). I will be using the 20V range when measuring AC current, and the DMM is accurate +/- .8% in this range.
http://www.sears.com/sr/javasr/product.do?cat=Electrical+Shop&pid=03482175000&vertical=TOOL&subcat=Multi-Meters%2C+Testers+%26+Accessories&BV_UseBVCookie=Yes
http://www.radioshack.com/product/index.jsp?productId=2102978&cp=&pg=2&origkw=audio+y-cable&kw=audio+y-cable&parentPage=search
