system without head unit?

While it has been argued over for quite some time, SQ is largely subjective, but there is also significant training given to iASCA SQ judges... Not as much for SPL competitors/judges. SPL is all about the mic; fixed, unwavering. Concrete, empirical measurements. SQ is all about the judge; a human. There are definite criterion that must be adhered to in the judging aspect, just as there are rules for SPL competitions. Pink noise is used for objective qualifications of "flatness". Imaging, sound power, frequency response, tonal balance... Many subjective aspects taken into consideration, but this is the very reason it is so important that SQ judges be trained correctly - to give FAIR and impartial numbers to all competitors. (Pretty much) ANYBODY could put eight 18s in a cutcab, feed them 1200 watts each, and make 155dB on a burp... The magic there would be the install... NOT everybody can make a car interior sound like you never want to leave it. The magic there is the presentation. Does the music sound like the artist wanted it to? How emptional is the presentation? Things like this all add up to sound quality. (Install points are counted as well in SQ.) Because of this, my opinion is that SQ competition is MUCH more difficult than SPL. (Not to minimize AT ALL what our own Jeff does...)It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."