Let's talk amps and box rise

[DaytonLax14 10+ year member]

What's up fellas?

Let's discuss amplifiers and box rise. If impedance is raised two times (or more) due to box rise, does that mean you should use an amplifier that is double the subs rated power?

For example say you have a sub that is 1500 watts rms and wire it down to 1 ohm, is it wise to purchase an amp that is rated for 3000 watts rms at 1 ohm? And then set your gain as you normally would (dmm, dd-1, etc)?

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[Dmac1991]

typically yes, that's the smart thing to do if you want your sub to see "rated"

But don't forget to account for electrical

 

[adulbrich 5,000+ posts]

If you're smart about how hard you push things, that's fine. It's what I'd do.

 

[cocoleveo7686 10+ year member]

well that would get very expensive for someone trying to get to get 4000 watts to 2 subs, then they would have to get a 8k amp. I think if you know your box rise you can wire to .5 and the amp wont see that. Ill let others chime im cause im kinda interested too. Like for me ill have to spend 1300 to get a 6k to see only 3k. Or some have told me i can go with 2 2ks at .5 and see 4k true for less money.

 

[Papermaker85 5,000+ posts]

What's up fellas?
Let's discuss amplifiers and box rise. If impedance is raised two times (or more) due to box rise, does that mean you should use an amplifier that is double the subs rated power?

For example say you have a sub that is 1500 watts rms and wire it down to 1 ohm, is it wise to purchase an amp that is rated for 3000 watts rms at 1 ohm? And then set your gain as you normally would (dmm, dd-1, etc)?

the Industry does have a standar on deriving RMS ratings but its not required. SO some companies do the logoical thing and put them in a test car and spply power to the woofer in different alignments to get a RMS power handling. its not a bad thing its alot simpler this way honestly.

id suggest you do the same. typically most companies underrat there product by 10-20% just incase someone decides to clip it. so typically as you pondered you can give them 10-15% more clean power once you see the impedance rise it should be fine..

what i like to do is suggest a RMS rating. a true long term power handling that the coil will basically last 20 years, them i like to do what i call a MUSIC rating. and typically i find that double the RMS number is good for music applications. for example a 2.5" flat wound coil using 28 gauge that has a winding length of 60mm can handle 600 RMS for 8 hours. i find on music they handle anywhere from 1000-1500 depending on the alignment motor streght etc etc. that probably wont work for other companies and te other companies would typically just rate it for 1kw and call it a day which is fine but you have people who clip them to death with 1k and burn in up in a few moths or even weeks.

 

[Boominburban]

My box is bolted down through floor. I don't have any box rise ..... sounds like it sux though ......

 

[Papermaker85 5,000+ posts]

My box is bolted down through floor. I don't have any box rise ..... sounds like it sux though ......

******* genius.

 

[Boominburban]

******* genius.

ikr .....

 

[DaytonLax14 10+ year member]

My box is bolted down through floor. I don't have any box rise ..... sounds like it sux though ......

Hahaha that made me chuckle.

Thanks for the input gentlemen.

 

[germanyt 10+ year member]

One of the reasons I like .7 and 1.4 ohm coils instead of traditional 1 and 2. Rise on a .7 load is still a fair bit over 1 ohm most likely but at least your not giving away so much.

 

[Boominburban]

Hahaha that made me chuckle.

Thanks for the input gentlemen.

You're welcome.... That's all it was meant to do ....lol

 

[ciaonzo 5,000+ posts]

What? No discussion about what is happening inside the region where "rise" is taking place?

Let's discuss what impedance rise really is. It is the progressive upward curve on the impedance profile plot that represents the inherent inductance of the driver. It gives you an idea of how high the driver may be able to reach in terms of frequency response, but not necessarily concrete.

This is not to be confused with the impedance magnitude of the driver at the fundamental resonant frequency. This is the spike seen at Fs on the impedance profile plot. It is indicative of where the driver is most efficient in terms of output simply because it is naturally resonant in this region. It takes very little input power to excite the driver at this frequency.

In reality, this spike that was mistakenly dubbed "rise" is the region where the amplifier struggles to maintain control over the driver because of the phase angles on either side of the spike/peak that is associated with the impedance magnitude. The enclosure can mitigate this spike to some degree but it is simply minimized and shift in frequency. Sometimes to great effect, especially if it is out of the passband.

 

[ciaonzo 5,000+ posts]

Here's a helpful link for a little more on the subject. --> Speakers: Impedance (Z)

 

[Papermaker85 5,000+ posts]

Here's a helpful link for a little more on the subject. --> Speakers: Impedance (Z)

you sucesfully wasted your life.. lol

 

[ciaonzo 5,000+ posts]

you sucesfully wasted your life.. lol

I fear you may be right, lol.