I have threatened to do an audio upgrade for months, but have finally come up with a plan, and want to run it by you guys in case you know of any issues that might pop up on Monday when this is scheduled to be done.

I have a JL XD700/5 amplifier and two 6x9 subs. Plan is for the installer to remove both the tweeters and 6x9s in the rear compartment, and to replace them with the new 6x9 subs, which will be powered by the sub channel on the amp.

The old amplifier is to stay where it is, except that it will be bypassed to hook up the OEM speakers.

Should I expect any issues with this plan?

 

Here is lots of reading material for you in regards to your upgrades https://www.northamericanmotoring.co...an-kardon.html

 

Good luck...here is s bit of a bump for ya...modifing the hk systems tend to pretty problematic...they were a pain on gen1 cars, generally requiring a full rewire to bypass an amp and work...

 

Thanks Braminator for the link. Nothing there about bypassing amp in the thread that I can find.

Zippy, have read about Gen 1, but nothing about Gen 2. If you have any specifics please share with me.

 

Here is some more info https://www.northamericanmotoring.co...questions.html

 

Braminator looks like we found the same thread and posted almost at the same time. Thanks!

I did find the thread below. Magicmini towards the end of the thread seemed to do a bypass without much issue. My shop specializes in some mini custom work for the local dealership, but I don't know about their experience with this situation. They do not seem worried at all, we'll see.

https://www.northamericanmotoring.co...questions.html

If anyone has experience with bypassing amp in a R56 HK scenario, love to hear from you.

 

Very important information about bypassing the amplifier in the HK system.

While the install is not finished as of this moment and is being done as I type, I am optimistic after hearing my installer say that there is nothing particularly difficult or weird about swapping out the amplifier and running signals from the head unit to the new amplifier.

I only hope he is correct and that he is not overlooking anything.

Install will be done in a couple of hours, I'll report back.

I'm hoping to have a used HK amplifier, 6X9s, and a pair of tweets up for sale by 4pm today.

 

Lok forward to hearing your results. Good luck.

 

If I understand your plan correctly, it sounds like you are planning on driving the front 6 speakers (woofer, mid, tweet) directly from a new amplifier? This is not a good idea. The signal from the head unit is full range, and the frequency division (the crossovers) is built into the HK amp. In doing what you describe, you will be sending a full range signal to all speakers. In addition to causing significant distortion by asking speakers to reproduce frequencies outside their capability, you will also have severe comb filtering as overlapping frequencies being produced from different locations add and null. The tweeter has a passive capacitor in series (@ 8kHz), but the midrange has no passive filtering. It is not capable of the excursion necessary to produce sub-100Hz frequencies at volume, so depending on how much power you send it you will likely exceed it's displacement-limited power handling ability and will have a mechanical failure (and terrible sound quality until you do). Neither the midrange or the tweeter has much thermal power handling ability, so if you are sending more than 20W their way you will likely burn them. The woofer is good up to about 35W. Both the woofer and the midrange have very nasty break-up modes that you will be hearing since you will have no filtering of the high frequencies.

I believe the xd700/5 has variable active filters on all 5 channels, so if your installer configures it so that the front woofer is run off 2 channels and the mid/tweeter off the other two channels and sets the HP/LP at about 120Hz you will be ok as long as you are careful with the power.

Removing the HK amplifier will prevent future software updates at the dealer - the DIS-ISTA/P will throw an error when it doesn't see the HK amp on the CAN bus.

What 6x9 subs are you having installed?

 

Kevin, you had me worried about things until I read you saying I would be ok with the crossovers in the amp.

We are configuring things to run the rear 6x9 subs with the sub channel of the amp, installing a remote volume control **** to adjust as needed.

The fader will be setup as you say; the rear will be the subs in the front door, the fronts will be the mids/tweets.

I have heard there is an issue with software updates with removing the amp. I'm disappointed this is the case. The installer found no fiber optic cable, etc. which is what I though would be present. Apparently the speaker wire conducts the information?

Will the dealer be hindered from doing diagnostics or other things after this is done? Will I have to have anything reset at the dealer after this is done?

I had wanted to leave the old amp in to prevent issues, but the installer saw no reason to do so.

 

I think you'll be "ok" in the sense that if everything is setup exactly right and you are careful with the power, you will avoid the problems listed above and you won't damage the speakers.

If I'm being honest though, I would not recommend that solution for several reasons, and I think you'll find the overall sound quality better in some ways and worse in others, and on balance not that great (certainly not good in terms of improvement vs. what you are spending).

If you haven't already, take a look at the HK section of this thread (https://www.northamericanmotoring.co...-upgrades.html), specifically this image:



That's the output signal from the HK amp. Red is the front woofer, green is the front mid/tweet. As you can see, there is DSP built into the amp, and the signal is highly modified. There is a little bit of room correction, and a lot of speaker correction. The HK speakers are far from perfect, and that speaker correction is mostly a good thing if you are using those speakers, especially the modification to the critical midrange speaker. You will be losing that modification with your new setup. Example: see the bump in the green line at around 220Hz? The small 3.5" HK midrange has falling response in this region, but because the 6" speaker is buried low in the door the midrange really needs to produce this frequency range (it falls in the critical male vocal band and is high enough in freq that your ear can detect directionality quite well, and the wavelength is short enough that your leg can/will reduce/block/alter the sound). This eq bump is needed to avoid a significant dip in the response here. With your new setup you won't be able to replicate this, and will either have to carry the 6" door woofer higher in frequency and bury that region low in the door (which you will be able to detect), or you will have a broad dip in response here. The HK amp already delivers as much power as the HK speakers can handle, so there is nothing to gain from more power. Bottom line: the HK system is as well optimized/engineered as it can be (given the component quality level), and the speakers and amp are matched. Replacing or modifying individual components is not recommended.

It's been discussed at length on this forum, but using 6x9's subs in the rear location presents a number of significant challenges. You will lose your rear fill (it will seem "empty" behind you, your rear passengers will have a very poor audio experience, and the sub-bass performance will still be quite poor (the rear location is not IB, there are no commercially available subs with ideal parameters, and two smaller speakers do not have equivalent parameters to one larger speaker, which is what you really need in this situation).

It is probably too late to be of any help now, but within the $$$ range you are likely spending the best improvement would be to leave the the HK system intact and add a larger subwoofer in an proper enclosure. This would maintain the rest of the system as is, and if you turn the bass tone control down a few notches on the HU you will eliminate the 70Hz exaggerated bump in the HK system and add decent performance below 60Hz - the two biggest weaknesses of the HK system. Plus you'd still have the amp in place which would allow dealer software upgrades (the amp is connected to the CAN bus, this is how the DIS knows it is there and how program changes are made).

 

Upgrade was disappointing, not unlike how you described, Kevin. Your predictions were spot on, sadly. The 6X9 subs were a total waste of time.

On a positive note, the front end is much improved running the 6" speakers at a higher freq.

The vocals pop now, imaging up front is much improved. That is a very nice change.

The muddiness that came from the 6" speakers is gone, and the shrillness from the tweeters is gone, the high end and mids are, overall, are much better.

I am most disappointed in the subs, it does sound empty behind me as you predicted.

I had used the 6X9 solution in another car and it worked SO well, but I can understand now why it worked in that car and not this one. The front speakers in the old car were coaxials, and the amp I used was very powerful.

I spent about $900 for this upgrade and still have to fix the rear speaker issue, I'm considering what to do. Overall things don't feel hopeless, but I do feel I spent too much for this modest upgrade.

I hate to admit this, but I should have saved my money and gone with your solution, Kevin. I cannot spend any more at this point, save for a couple hundred for anything that might salvage this situation.

 

Spoke with technician, he suggested going to a six channel amp and running full range speakers in the rear in place of the subs.

 

I can't say I'd recommend that. The trouble is that the amount of rear volume is key - not enough fill and you have no spaciousness (seems empty behind you), too much and you completely destroy any imaging and sound stage (I've written here previously about why that is, search through my old posts if you are interested). With your current setup, you really need to get low frequency output out of your rears since you have no other source for it. That means driving the speakers rather hard. If you did this with full-range rears you would have far too much mid and high frequency coming from the rear, and no more imaging and sound stage. The only way to make this work would be if you were able to eq the rears to adjust the low/mid-hi freq balance. You'd really need a shelving filter to do this, traditional eq would not be the way to go. Given what they've done so far, I suspect this is well beyond the capability of the shop you are using.

If you look at the green line in the graph above, and imagine flattening it, you'll see where the differences you hear are coming from. You've basically elevated the region from 1kHz and up relative to the other levels, as well as eliminated the roll off above 8kHz. This will definitely sound noticeably different. Vocals will indeed "pop", especially female vocals, because they are boosted relative to the rest of the freq spectrum. I think over time, once you've had a chance to listen to it more and become familiar with the differences by listening to specific tracks, you will start to notice the broad freq dip below 300Hz (male vocals will now sound subdued relative to female vocals).

This is a decidedly good thing, as you've found. Again, looking at the graph above makes it easy to see why. Exaggerated low frequency sells systems in a showroom. The obscene level of eq boost centered at 70Hz is the biggest failing of the HK system, but it gives a clear showroom difference between the HK and the standard 6 speaker system. It sells, and that's why they did it. Removing this is, in my view, the best outcome of your current setup.

Well, I of course wish you had too, but that's an easier decision to make in hindsight. Sorry I couldn't have been there to help you in time. Adding just our subwoofer system to the HK is a great way to go for about what you'll have ended up spending on your current setup.

If it were me, I wouldn't continue and likely just throw good money after bad. Rather than buy a new 6-ch amp, I'd reinstall the HK rears and drive them off the HK amp. Buy the best proper sub and enclosure you can afford and drive that from the 5th channel of your current amp, or save your pennies and buy our subwoofer - we will soon be offering it without the amplifier and wiring harness (at least on a trial basis).

 

Kevin, you've helped clarify what is going on with my car, and while it's too late to undo much of what I've done without wasting the money spent, I'll try to salvage things best I can.

The HK amplifier is already removed, it's been taken out. Would you reinstall it then? I guess I'd need to do that to power the 6x9s.

As an afterthought, I do have a JL 360/4 gathering dust, it would power the 6X9s also.

Do you have an estimated price on how much you'll offer the sub without the amp? Since I'm a videographer/phootographer, I use the boot for my camera case, so your stealth solution would be ideal.

 

It occurs to me that using a second amp to power the 6X9s will leave me with no volume control for those speakers. Am I mistaken?

 

Yes, I would reinstall it.

Around $700.

 

Thanks, Kevin. Keep us posted on the status of the sub kit w/o amp.

 

Wow, what a difference tuning the amp properly makes.

I played with it last night and it is vastly improved. I flipped a switch on the sub channel, tuned and adjusted things on the head unit, and it is amazing.

The bass on Sexyback actually made the hair on my head vibrate, very weird.

The sound system has completely changed. It's not perfect: full range 6x9s and a sub would obviously be better, but with the system tuned it is SO much better.

 

After spending about an hour this morning tuning the amp, and head unit, it is very very nice.

Audio gets much louder than I can stand. My friend heard me from almost a block away today when I was driving up to her house. Bass is awesome.

Imaging is much improved running the 6x9 at full range. Full range speakers would produce better imaging, I know, but it's not bad at all as is.

I'm hearing parts of the music I never heard before.

Overall I'm pretty happy for now.