Acura RSX, ILX and Honda EP3 Forum banner

KDC-X701 Head Unit with Bose Amp / Sub - Need Help

2K views 4 replies 2 participants last post by  shoegazer 
#1 ·
I apologize as I realize the Bose amp to bypass or not to bypass issue has been much discussed on here, but I feel like I've gotten to a specific enough question that I just wanted to post a new thread, as I couldn't be certain I was doing this all right trying to piece together info from varying threads...the 4v output to the amp is my main concern on whether I should go 70-1721 or 70-1725 for the ideal system install.

So I currently have the following gear:

Kenwood Excelon KDC-X701 Head Unit (4V output / 6pre-amp RCA outs)
2 Pioneer TS-A1686R speakers in front
2 Pioneer TS-A1685R speakers in rear
Bose Amp / Sub

Already in-hands from Crutchfield's recommendation:
Metra 70-1721 Harness
SLC-4 Line Output Converter

Though I am reading people's recommendation for the 70-1725 harness, the Crutchfield guy said they would error on the side of caution by using the 70-1721 and SLC-4 as to not burn up the Bose amp/sub with the 4v output that the KDC-X701 provides. Any arguments?

...I really don't want to spend more money on a new rear sub or take up trunk space with a box as I'm mostly content with the stock amp/sub. Or, would the ideal setup be the 70-1725 harness with some sort of resistor installed before the amp to reduce the voltage? Can anyone provide a DIY including parts I'll need if that's the ideal route to go for best audio quality that won't burn the sub? Or is that basically all the SLC-4 is doing anyway?

If I go the 70-1725 route, which of the 6 pre-amp outputs am I connecting the RCA's to on the back of the HU to run to the Bose amp?

Also I may be looking at the Infinity BassLink 8" powered amps to slip under my front seats (if they'll fit) to fill in the bass in the future depending on how this all goes. Anything to keep in mind there? Would I just get RCA splitter adapters to branch the pre-amps out to all 3 subs if I used the Bose sub and then an Infinity BassLink under each front seat? I'm trying to minimize taking up space in my car, so I'm not interested in putting in a new bass/amp/box combo anywhere. I'll go without the extra bass if I can't wedge the Infinities under the seats.

Finally, I will be selling off my Bose HU with the Aux-Input mod that I did here shortly in Los Angeles if anyone is interested...it works well save for the hiss if you charge your phone. I did notch a few holes at the top of the dash cover so that I could run my USB charging and Aux cables up through the dash and out of the top of the HU to my phone that sits in a mount above...not terribly noticeable, but maybe not the cleanest look if you aren't going to run your own cables out of them. Please PM me if you want to buy as to not litter this thread. I will post on here if I sell it, so otherwise it's up for sale.

Thanks
 
See less See more
#2 · (Edited)
Alright, well I've gotten everything in and working. No hiss from the SLC-4 that I can tell. Made sure to ground it to the chassis. There is a hiss if I crank the head-unit volume up high with my phone volume low, but I believe the ideal scenario is to set the output volume (phone) to 90% to avoid overdrive and then set the speakers from there?...doing that, everything sounds pretty clean.

I was running out of time today (on top of being impatient) so I ended up twisting the gains on the SLC-4 all to full to ensure they were all at the same level rather than trying to make tiny adjustments on each, so I will probably eventually have to go back in and tone those down if those could be affecting something? Does the SLC-4 truly create a gain, or is it just not being as much of a resistor if turned to full gain?

The KDC-X701 head unit while more convenient with features and gives me the ability to go louder doesn't necessarily make the audio-quality sound any better than my Bose head unit running through my Pioneer 4-way speakers...about the same. Is there something I'm missing, or was the sound not really going to improve over my Bose head unit anyway? Swapping the Pioneer speakers in for the Bose speakers was an incredible difference though. The Bose speakers even looked and felt like junk when taking them out.
 
#3 ·
Generally...

70% seems to be the 'unity gain' setting on most players/pre-amps/etc where you're feeding the output to a final stage of amps. Less that than is turning down. More that 70% is adding gain.

Of course... normalized digital files and other stuff can make this situation one where you may bed to pad (cut) or boost a line level.

But 70% is a good starting point. And it's likely that it is the level that the engineers aimed for when designing all this stuff.

I'll re-read the other stuff re: the 4 volt wire and Metra harnesses later. Not enough coffee on board yet.
 
#5 ·
Never enough coffee. But some general thoughts:

Line output converters are famously noisy. The factory Bose sub is, IMO, not worth the trouble.

If it were me... I'd ditch everything Bose and go with your new system, hardwired to the new speakers with whatever harness does that.

You can add an aftermarket sub (and connect it to the sub pre-amp output on your Kenwood). Of course, it would need a power supply (and maybe a 'remote power' signal connection). Or... you could just let it run off of a switched power supply.

It's likely that no amount of 'hyper bass' settings on the Kenwood, going through the 5-6 inch speakers, will deliver the 'miami bass' effect. But it may be tolerable.

For me... a clean signal path, free of distortion-adding magic boxes, is optimal. The Kenwood delivers 22 watts RMS per channel. Normalize your music files and you may have a punch little system all on board the Kenwood.

Sorry I don't have an answer for the Metra question. I'm just not that familiar with it.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top