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Am I missing something or just lucky that my amp hasn't fried?


Raytheon

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I have been doing a much needed refresh on my system recently and noticed something very worrying. I just switched from a sealed enclosure for my two old Punch P2's, to a T-line enclosure with some better quality wiring.

The sound quality has improved; however, I noticed that my bass output seems lower that the sealed setup. I have taken a closer look into my sub wiring and I am concerned that I have had these wired wrong for years.

I have a Kenwood KAC-8103D Mono amp (500W@2 Ohms) and two older model RF Punch P2D212 (RMS 250W@2 Ohms). Looking at my old wiring, it seems I may have wired it down to 0.5 Ohms. I am assuming at the time (approx. 4 years ago) I thought the extra sub connections on the amp meant it had more than one channel.

I am willing to guess that because I have re-wired them correctly to 2 Ohms, the bass is not as loud.

My question now is, how did I not burst into flames?

I have not had any problems with this setup other than turning the input sensitivity down due to blown fuses. I find it odd that nothing has been damaged running this system at such a low impedance.

What signs of damage should I look for in the audio components or the vehicle itself? Could the relatively low wattage requirement have saved me?

Here are examples of the wiring before and after:

Before:                                                                                                                    After:

2_2ohm_dvc_05ohm.jpg8863dd7.gif

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Since a speaker is a reactive load the impedance will change with freq. When you're playing music the impedance isn't going to be 0.5 ohms, it will constantly change. 

If you want to see this in effect, hook up a ohm meter to your speakers and then touch them or make noise in the background, the reading will jump around.

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I would put it back to .5 but that's just me. I have seen a lot of different amps that can do .5 even though its not rated for or warranted for .5 ohms.

91 C350 Centurion conversion ( Four Door One Ton Bronco)

250A Alternator (Second Alternator Coming Soon)

G65 AGM Up Front  / Two G31 AGM in Back

Pioneer 80PRS

CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage

CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill

FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon)

Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon)

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I suppose it is a testament to the quality of components to operate issue free nearly 4 years that far out of their specified rating.

It does make sense that the resistance changes as the speakers are operating, and explains a lot considering I am fairly conservative in terms of settings and song selection.

I hope I am safe in assuming that many of the cases of catastrophic failure are from pushing the components to the limits while at that configuration (i.e. in competitions).

Before I consider switrching back to the .5 Ohm wiring, I will do some adjusting on the amp settings now that I have a more stable setup. It is possible I can boost the bass a bit to possible match what the output was at that rating.

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You're more likely to damage stuff by wiring at 2ohm and boosting and sending a clipped or distorted signal. It also sounds like you are just guessing with the amp settings, how did you set your gain? Another thing to consider, when those subs were in a sealed box they had a lot of preotection from over excursion. Now that they are in a quarter wave there is basically no protection

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You do have me there, I have not taken the time to truly tune the system. But that is due to my car audio situation has been in a sort of flux for a while. I have been trying do a custom touchscreen / tablet install in the dash, but due to my inexperience in custom fabrication, lack of time, and money, is has not been finished yet. I also do not have a true head unit, just an EQ and my phone into the auxiliary input.

I just did a basic tune using a -10db 50Hz track and a multimeter. With the EQ sub level set half way, amp bass boost off, and both main volume and phone volume set at approx. 90%, I set the input sensitivity toe get the correct voltage output needed for 500W RMS @ 2 Ohms (approx. 31.6V).

We will see how that sounds tomorrow on my way to work.

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If you wanted, you could check the tool map here for people in ur area with the SMD tools like a DD1 and CC-1. U cant rent/borrow the tools from them. Just go to the "SMD PARTNERS" section. Then D'amore enginering's threads, the first pinned post should be the tool map of everyone offering out their smd tools to locals in their area.

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