[Redzsi]

Hi! I have Harman kardon system in my 2017 bmw, and the bass was awful and I bought a sub with amp to the trunk. The problem is, if I turn up the volume in the car, the sub not getting louder with the sound system. It's just staying in like 50-60% and the mid and the high speakers gets higher. So if I listening it like 40-50% loud, it's good. But when I turning it louder, just the mid and high speakers gets louder. I have a jbl amp with 300-400 rms watt with same watt sub. I tried it with much stronger setup but it did the same thing. In lower and mid ranges was stronger but when I get higher ranges the sub stuck in 50-60% ranges. Please help!

[DreamerJoe]

have you tried adjusting the gain on the amplifier? try turning it up a little bit, maybe a 1/4 of the way

[Redzsi]

The gain is almost max. it's feels like the car not letting to get higher ranges to the bass. Thanks for the response!

[Billfitz]

How did you connect the sub to the system? What sub is it?

[Gaffer]

Yep, more info needed.

Was it wired in as per Technic's harness (i.e. boot sub getting signal from underseat sub signals)? If wired in via rear speakers then they're XO'd higher and won't be giving an adequate signal to the sub.

If wired from the sub feed, what gain have you set the LoC on? (i.e. is it clipping and the boot sub going into "protection mode" or something)?

What is the gain on the boot sub? What is the power of the boot sub?

[Billfitz]

Originally Posted by Gaffer

What is the power of the boot sub?

That may be the issue, but probably not in the manner that most would assume. All drivers have a mechanical limit on their output, based on the maximum cone excursion. It's seldom apparent with midbasses or midrange speakers, which tend to run out of thermal power capacity before they run out of excursion. Woofers and subwoofers, however, may run out of excursion at well below the thermal rating. When that happens more power applied does not give more output.

[Encanto]

Originally Posted by Redzsi

Hi! I have Harman kardon system in my 2017 bmw, and the bass was awful and I bought a sub with amp to the trunk. The problem is, if I turn up the volume in the car, the sub not getting louder with the sound system. It's just staying in like 50-60% and the mid and the high speakers gets higher. So if I listening it like 40-50% loud, it's good. But when I turning it louder, just the mid and high speakers gets louder. I have a jbl amp with 300-400 rms watt with same watt sub. I tried it with much stronger setup but it did the same thing. In lower and mid ranges was stronger but when I get higher ranges the sub stuck in 50-60% ranges. Please help!

Most probably this sub input signal is coming from the rear speakers.

[Redzsi]

Thanks guys for the response! So I have 4 gauge cables, with 300w jbl 5501 amp with 300w Sony sub. I did the line from the front right sub. The LOC is on max and the gain is almost on max like 80%. I thought 1 of the subs under the front seats gonna be enough for the line.

[Redzsi]

Originally Posted by Billfitz

That may be the issue, but probably not in the manner that most would assume. All drivers have a mechanical limit on their output, based on the maximum cone excursion. It's seldom apparent with midbasses or midrange speakers, which tend to run out of thermal power capacity before they run out of excursion. Woofers and subwoofers, however, may run out of excursion at well below the thermal rating. When that happens more power applied does not give more output.

I think you are right. The bass line has an output limit. I hope somebody knows that answer for that problem.

[Billfitz]

I could tell you how much power the sub driver is capable of taking before it runs out of excursion if I had the driver Thiele/Small specs and cabinet details. As already mentioned if you pull the signal from one of the underseat woofers you won't get the full range of the low frequency content, as the OEM amp high passes and equalizes the output to the woofers. The best way to do it is with a harness that taps the signal before it enters the OEM amp.

[Redzsi]

Originally Posted by Billfitz

I could tell you how much power the sub driver is capable of taking before it runs out of excursion if I had the driver Thiele/Small specs and cabinet details. As already mentioned if you pull the signal from one of the underseat woofers you won't get the full range of the low frequency content, as the OEM amp high passes and equalizes the output to the woofers. The best way to do it is with a harness that taps the signal before it enters the OEM amp.

So if I'm getting right, I have to search for that cable what is going in the oem amplifier, and find the sub line cable.

[johnung]

Originally Posted by Redzsi

So if I'm getting right, I have to search for that cable what is going in the oem amplifier, and find the sub line cable.

Have you checked the Technicpnp website? I bought a harness for $50 that split the signal wires right out for me to feed into the LOC. Photos attached.

[Redzsi]

And you don't have this problem? If this thing will solve my problem I will order it right away!

[johnung]

Originally Posted by Redzsi

And you don't have this problem? If this thing will solve my problem I will order it right away!

No problems at all with this harness!
I'm running an Audio Control ACM-2.300 amplifier. It has 300 watts that are split into two separate 150 watts RMS into two 8" Earthquake SWS-8Xi (2-ohm) subwoofers. The AudioControl has a built-in LOC that is rated to handle high level 40volt speaker inputs coming from the H/K stock amplifier. Right now I have the gain set halfway and it is not maxed out.
Hope this helps!

[Billfitz]

Originally Posted by Redzsi

And you don't have this problem? If this thing will solve my problem I will order it right away!

You have two separate and distinct issues. One is the connection from the head unit to the sub amp. That is probably preventing the sub from playing as low as it should. Fixing that will probably get you a better result, and it might even seem louder. But if the sub has inadequate headroom, either electrically or mechanically, that problem won't be affected by fixing the sub input connection.

[Encanto]

Originally Posted by Billfitz

You have two separate and distinct issues. One is the connection from the head unit to the sub amp. That is probably preventing the sub from playing as low as it should. Fixing that will probably get you a better result, and it might even seem louder. But if the sub has inadequate headroom, either electrically or mechanically, that problem won't be affected by fixing the sub input connection.

HK OEM HU outputs to the OEM amp is MOST -cannot be tapped for an aftermarket sub amp. OEM amp woofer outputs are tapped for an aftermarket sub amp.

[Redzsi]

Thank you guys! I I just ordered this cable I hope this will solve my problem. I will let you know soon as I can!

[psyki]

I have a the HK system and bought a Wavetech Link2 along with the PNP harness from Technic in order to wire up my JL Audio 10" and JX250 amp, it's my understanding that you need a dedicated LOC to power your amp due to the 40v output, unless the amp is designed to handle that (many are not). With this setup I have the "input sensitivity" on the amp all the way down and the gain on the Link2 at about 60%. Sounds terrific and bass scales with the volume as it should.

[johnung]

Originally Posted by psyki

I have a the HK system and bought a Wavetech Link2 along with the PNP harness from Technic in order to wire up my JL Audio 10" and JX250 amp, it's my understanding that you need a dedicated LOC to power your amp due to the 40v output, unless the amp is designed to handle that (many are not). With this setup I have the "input sensitivity" on the amp all the way down and the gain on the Link2 at about 60%. Sounds terrific and bass scales with the volume as it should.

I agree with your comment...

"you need a dedicated LOC to power your amp due to the 40v output, unless the amp is designed to handle that (many are not)."

In my research I found a bunch of amplifiers that claimed to have speaker level inputs but they often did not specify a value. Luckily a forum member cautioned me that the H/K amplifier speaker output signal can be up to 40 volts. I finally found that the smaller Audio Control amplifiers have speaker level inputs that are rated to handle 40 volts. It was important to find a combo unit because I didn't want to give up space for a separate LOC and a separate amplifier. The AudioControl ACM-2.300 fit my needs perfectly.

[Redzsi]

So I just got the cable what you recommend for me. Unfortunately didn't help. It's just a little bit stronger in the lower and mid range. But in the high ranges still really weak. I tried almost everything. I put in a better LOC (LCi2), better cables, stronger amp, stronger sub, Technic pnp cable. But none of these are the answer. I don't know what should I do right now.

[Billfitz]

What do you mean by high ranges? If you mean high frequencies subwoofers aren't supposed to reproduce high frequencies, or midrange for that matter.

[Redzsi]

Originally Posted by Billfitz

What do you mean by high ranges? If you mean high frequencies subwoofers aren't supposed to reproduce high frequencies, or midrange for that matter.

I mean if I turn up the volume. The low range (sub) stays on 60-70% and the mid and high range getting louder. If I turn the volume to max I'm not hearing the bass at all. Just only mid and high. My amp is set to 60hz. It's really weird.