Running an amp at .25 ohms

[Matt A 10+ year member]

Hello,

I am getting ready for an upcoming competition and currently i am running my 4 hdc3s at 1 ohm off a 3500d.1. I'm not 100% positive what the impedance rise is but I would guess it would double in my enclosure. I was thinking of running the amp at .25 ohms for the competition (never daily). What are your thoughts and what is the maximum time I should burp it? Thank you.

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[Imtjnotu 5,000+ posts]

if the amp can handle it and u can hold an electrical system thats well above 14.4 then it may be possible.....even if it is for a comp u may end up killing off that amp.....

 

---------- Post added at 09:38 AM ---------- Previous post was at 09:38 AM ----------

 

i wouldnt run it on less then 15volts

 

[ahole-ic]

The gains won't be worth the risk. If you can hold above 12.6v the amp SHOULD make it, but you never know. You'd be much better off just paying for a test n tune at your local shop, or with thegreatestpenn. You will get MUCH larger gains from finding your freq, tweaking your interior etc, than you will from the mediocre gain .75 ohms less impedence will give you.

 

[Matt A 10+ year member]

ic ic so just to make sure I understand... if the box raise doubles at 1 ohm, it does not double when its wired to .25 ohms? the box raise is added not multiplied? and in the winter time my voltage would be a steady 14.7 volts but in the summer months its been at about 14 without music.... im guessing the weather really affects it

 

[MONSONwarrior Premium Member]

ic ic so just to make sure I understand... if the box raise doubles at 1 ohm, it does not double when its wired to .25 ohms? the box raise is added not multiplied? and in the winter time my voltage would be a steady 14.7 volts but in the summer months its been at about 14 without music.... im guessing the weather really affects it

Your voltage goes down when the alt is hot, so yeah, weather affects it. I'll charge 15 in the winter and 13.8 in the summer, it *****.

 

[ahole-ic]

ic ic so just to make sure I understand... if the box raise doubles at 1 ohm, it does not double when its wired to .25 ohms? the box raise is added not multiplied? and in the winter time my voltage would be a steady 14.7 volts but in the summer months its been at about 14 without music.... im guessing the weather really affects it

Correct. It is added and not doubled.

 

[Matt A 10+ year member]

hmmm.... well i guess the only reason i would jump on the idea is because audioque said it should be fine and i have a volt and clipping indicator right in front of me on the dash... so on the whole no go?

 

[ahole-ic]

hmmm.... well i guess the only reason i would jump on the idea is because audioque said it should be fine and i have a volt and clipping indicator right in front of me on the dash... so on the whole no go?

It's your stuff. If you want to, go for it. I don't think it will help you much. It's not like you're eeking every tenth out as it is. Controlling impedence rise is really only an option after everything else is tweaked as far as it can go.

 

[Matt A 10+ year member]

ic ic.. well i will not do it i guess because i just got the amp repaired so unless it will do wonders i wont do it... for some reason when i metered it last time it was a 145 when the woofers were 2 minutes old.... im not sure if thats a box issue or a wiring issue tho

 

[ahole-ic]

ic ic.. well i will not do it i guess because i just got the amp repaired so unless it will do wonders i wont do it... for some reason when i metered it last time it was a 145 when the woofers were 2 minutes old.... im not sure if thats a box issue or a wiring issue tho

Why is a 145 an issue? Low tuned, large box and not a huge amp. That's about right for the way you have it set up.

 

[bhsdriller 10+ year member]

I wouldn't hesitate to run that amp at .25....just for a burp though, wouldn't do it for daily

Just watch your voltage

 

[Matt A 10+ year member]

well if you c a lot of other setups online with the similar setup they are well into 150.... in my designs i was thinking a big box and low tuning would be the best of both worlds as far as efficiency with the power i have and the strong low end air flow.... i was expecting 5 db more than i got i guess

 

[mlstrass 5,000+ posts]

I wouldn't hesitate to run that amp at .25....just for a burp though, wouldn't do it for dailyJust watch your voltage

First sensible answer in here. Used to run 4 AQ3500's at 1ohm daily and .25ohm for burps. Would gain 2.7dB's when wiring down. You'll have to roll up the volume as they won't pause burp at .25ohm.

Amp will soft protect at 10.6v, but you should not drop that low on a 3-5 second roll up burp. Also some clipping is fine and normally you'll meter louder. GL at the comp...

 

[bhsdriller 10+ year member]

Forgot that...roll into the volume

 

[Matt A 10+ year member]

hmmm so start at 0 volume and cranck it to 3/4 volume... ive never heard of that constraint feature in an amp before but u learn something new every day lol... i mean the woofers will be able to take pretty much any power level i throw at them...its the amp im worried about... but does my electrical look like it can handle 3 second bursts for iasca and db drag spl? ( i doubt it will handle bass race or basss boxing with the electrical i have)