Signal Analysis

Before I get into the build pictures of the trunk, I wanna run through the various signal analysis I performed during the build.

As with any vehicle that requires tapping after the OEM amp, having a good understanding of the stock signal is vital. In the Genesis Lexicon system, the OEM amp has three outputs that will be utilized. They are the midrange/high channel, the door woofer channel, and the subwoofer channel.

Using my TrueRTA and Fast Track Pro, here are the measurements I took at the amp speaker outputs.

Midrange and high:



Door woofer:



Subwoofer:



The subwoofer and door woofer signals were sent to the Mosconi HLA-Sum device, and here the analysis of those two signals combined after adjustments:



The OEM tweeter channels were fed into channels 1/2 on the DSP, while the summed signal from the HLA-SUM were fend into channels 3/4. Using the mixing and input EQ feature on the 6to8DSP’s software, I was able to achieve a signal that looked like this at the RCA output of the DSP, not too bad considering where I started from:



The signal from the DVD changer is fed through channels 5/6 on the DSP…just for giggles I also analyzed this line signal…little surprised, it didn’t need any adjustments. Hehe:



One thing I noticed was that the OEM master volume control did NOT alter the signal output on the amp, which was very surprising. But here is the plot comparison of that, the lower line is at volume 15, middle at volume 30 and top at volume 40…note that the response is virtually identical, just at different levels. This means that we can use the stock volume knob as the master volume control with little issue.



After my initial tuning session, I basically came up with three separate presets.

Preset 1: Driver oriented two channel, OEM signal source set to LOGIC 7 OFF, center channel speaker turned off. This is the daily listening mode. The final curve here as measured by my dual mic RTA setup looks like this, again this is just a preliminary tune:



Preset 2: Two seat listening, OEM signal source set to LOGIC 7 ON, center channel speaker turned on, time delay and levels were adjusted to effect as good of a sound stage as possible for both seats. This is the end result curve:



Preset 3” DVD changer signal source…this is for competition purposes and the final curve looks like this:



Overall, the OEM signal is a lot better than I thought, it is reasonably clean with a decent SN ratio for a stock post amp install…the DVD changer is a bit quieter and I hope to extract even more from it in the near future, but the oem signal source does an admirable job overall…perfectly acceptable for SQ listening. The two seat listening still needs to be fine tuned more, right now, I got it to sound pulled about 2-3 inches to each side depending on the listener seating position, having to work with the car’s inherent logic 7 system has its challenges, but I think over time, it can only get better. Tonality wise there isn’t much of a difference between the two settings.