hey all

I've got a TS-W306C sub (400wrms) and its currents being underpowered badly (220wrms) and I'm going to get a new amp for it but I'm wondering if its better to underpower the sub or overpower is slightly (the 2 amps I'm looking at are 350rms and 450rms respectively).

So whats better for the sub in the long run?

its better to have an amp that puts out more rms than the sub
if the amp has more power you can just lower the gain and you shouldnt have any problems
plus if you get a decent high power amp you can upgrade in the future with no problems

get the 450 rws, it will be better in the long, you get maxium potential out of the sub. Getting this amp means it doesn't need to use 100% of its power, it has to work less, but i'm limited to know why this is good other then maybe no dips in sounds quailty from the woofer etc

get the 450 rws, it will be better in the long, you get maxium potential out of the sub. Getting this amp means it doesn't need to use 100% of its power, it has to work less, but i'm limited to know why this is good other then maybe no dips in sounds quailty from the woofer etc

its better to have more power to advoid "clipping"
just means if you descide to increase the db your amp can put out the power your asking it to without damaging your voice coils

I heard a wierd rummor a few years back that you are best to buy:
"An AMP that puts out half the power of the Sub."

I assume the person that told me this is wrong and it should be the other way around - still, it would be nice to have this clarified.

I think they may have said this for a Sub that had a MAX POWER XXX rather than the more correct RMS - (Dodgy manufactures don't put RMS on as it make to look better to have the comibined Output)

In technical terms it doesn't matter as long as the amp is tuned for the sub. Proper tuning will avoid overpowering the sub (allowing more power into it than it can handle) or underpowering (where the signal becomes clipped). But as Mr Roberto said it's better to have a more powerful amp to allow for upgrading later and a more powerful amp won't have to work as hard to do the same job.

I heard a wierd rummor a few years back that you are best to buy:
"An AMP that puts out half the power of the Sub."

I assume the person that told me this is wrong and it should be the other way around - still, it would be nice to have this clarified.
That's total rubbish, you can buy an amp that has any amount of power, just depends on how loud you want your sub to go.
A 500wrms sub will take 500wrms, a 200wrms will give a sub 200wrms, no more, so you're effectively using your 500wrms sub as if it was a 200wrms sub. However if you wanted to use a 1000wrms amp, you would simply match the output signal and 1/2 it on the gain control and limit the amp to only run at a maximum of 500wrms.

its better to have an amp that puts out more rms than the sub
if the amp has more power you can just lower the gain and you shouldnt have any problems
plus if you get a decent high power amp you can upgrade in the future with no problemsYep that would be the way to do it.

hey all

I've got a TS-W306C sub (400wrms) and its currents being underpowered badly (220wrms) and I'm going to get a new amp for it but I'm wondering if its better to underpower the sub or overpower is slightly (the 2 amps I'm looking at are 350rms and 450rms respectively).

So whats better for the sub in the long run?


This would be worth a read!!! (http://forums.justcommodores.com.au/showthread.php?t=49480)

This would be worth a read!!! (http://forums.justcommodores.com.au/showthread.php?t=49480)
Not really anything in there relevent to the question though...

Best bet is to ignore any power specs besides RMS. Max power etc is useless...

It is not better to under power or overpower a sub both will do damage. If you have a sub that can handle 3000 w rms, just because you like the sound of a sub, it doesnt mean you need an amp capable of producing that much power to enjoy the sub at normal listening volumes.

Ideally to get the best use out of the sub that you paid good money for. You would want an amp that can put out more power than the sub can handle then trim the gains appropriately.
Alternatively if you have an amp that cant put out that much you need to be aware that you can still damage the sub. If the amp is driven to clipping (by cranking the gains up usually) then the sub itself can be prone to overheating as the subs 'clipped' movement may not allow enough air into the motor to cool it.

(and it will sound horrible)

But at the end of the day you can power a sub with 200 w rms if you please, just make sure you set the gains correctly, and that you dont ask more than the amp can deliver.

Peace

Tim

That's total rubbish, you can buy an amp that has any amount of power, just depends on how loud you want your sub to go.
A 500wrms sub will take 500wrms, a 200wrms will give a sub 200wrms, no more, so you're effectively using your 500wrms sub as if it was a 200wrms sub. However if you wanted to use a 1000wrms amp, you would simply match the output signal and 1/2 it on the gain control and limit the amp to only run at a maximum of 500wrms.

correction..
a 500wrms sub is made to run at 500rms continuously but in spl contests competitors actually feed subs many times their rms rating but for a few seconds. You are way off saying they can handle no more. With a subsonic filter you can feed them even more.
also putting a 1000 wrms amp at half gain does not put out 500rms.
am amplifiers gain is to match your head unit output. ie headunits with 8v preouts should have the gain lower. All you do by running full gain is increase distortion and reduce output.

correction..
a 500wrms sub is made to run at 500rms for a prolonged period but in spl contests competitors actually feed subs many times their rms rating but for a few seconds.
also putting a 1000 wrms amp at half gain does not put out 500rms.
am amplifiers gain is to match your head unit output. ie headunits with 8v preouts should have the gain lower. All you do by running full gain is increase distortion and reduce output.
Yeh for SPL comps...and how often do you see a sub blow in an spl comp? I've only been to 3 spl comps and i've seen about 4-5 systems go down.

bold - I never said halving the gain would halve the output, i said matching the amps gain to the HU signal and then halving that would give you half the output of the amp (in theory, not all amps will output the exact same).

you said a 500rms sub can handle no more.... if thats so then what is the peak power measurement for.

i think the only reliable way to get 500rms from a 1000rms amp is to go up from 4 ohms to 8ohms if the amp can

The systems you have seen go down could be 100 reasons and not that "their amp was too big"

I have been competing since 2000 and have yet to blow anything other than a fuse.

you said a 500rms sub can handle no more.... if thats so then what is the peak power measurement for.

i think the only reliable way to get 500rms from a 1000rms amp is to go up from 4 ohms to 8ohms if the amp can

The systems you have seen go down could be 100 reasons and not that "their amp was too big"

I have been competing since 2000 and have yet to blow anything other than a fuse.
Sorry i should have stated it can take no more than 500wrms constantly :P.

Or you could match the signal strength from the HU and halve it? It's not exponential i don't think.

I know 2 of them blew subs, but they were running amps twice as poweful and you could smell the subs voice coils were gone.

Cool you're very lucky :).

cool.

Leo from Doran Pro Audio runs his Soundstream subs with a 4000w RMS Clif Designs amp
Anthony from Speed of Sound runs the same subs with a 7000w RMS US Amps amp

Neither have blown subs but obviously thats pushing your luck and admittedly not everyone wants all the batteries you need to get 18 volts to your amp !

Never heard about halving your gains to get half the wattage. I was under the impression that the amp always produced its RMS rating (depending on vopltage and music transients)and increasing the gain merely increased the amps "starting point" from where amplification starts, so to speak.

Never heard about halving your gains to get half the wattage. I was under the impression that the amp always produced its RMS rating (depending on vopltage and music transients)and increasing the gain merely increased the amps "starting point" from where amplification starts, so to speak.
The gain is just a sensitivity adjustment. The gain is similar to a volume control in that it turns the volume up and down, but in a car audio system using one or multiple amps, we only have one volume controller (the headunit) unlike in say an AV system where we use the amps volume controller.

Given this the gain should always be matched to the headunits output. An amp with the gains on full is bad for a few reasons.

-You cannot use the headunits full range of volume options - Say the headunit goes up to 35 and by the time you hit 15 the sub is already distorting, so instead of having 35 usable increments you only have 15.

-You risk blowing your gear, especially with drunk friends in the car who will crank up the tunes straight away, if this happens then you will easily damage equipment

- Lower gains allow you to use a higher voltage output (stronger signal) from the headunit. As the headunit volume needs to be higher. This is less susceptible to interference. (providing your headunit preamps dont distort at full volume.)

To set your gains. Find a CD you know well, turn the gains on minimum, turn the headunit up to the highest point before distortion (usually between 80% and 100% depending on quality)
Then slowly raise the gains until distortion sets in, once you hit this point dial it back a bit.

You should now be able to turn the headunit up to full without distortion - your gear should be kept safe and you can use the full range of your headunit.

Peace

Tim

Yup tims way is the best way of levelling your system i believe it's called.
But just one more thing some amps actually have written on the gain control voltage signal strength so you'll be able to use this to match your headunits output or use it as a base to start off with when leveling.

You should now be able to turn the headunit up to full without distortion - your gear should be kept safe and you can use the full range of your headunit.
Tim

I have a DSP that dislays when my H/U is clipping and no H/U would go to full without distortion. I just leave my AVH5700DVD volume at around 20 and can go to full on the DSP volume

I have a DSP that dislays when my H/U is clipping and no H/U would go to full without distortion. I just leave my AVH5700DVD volume at around 20 and can go to full on the DSP volume
Depends what headunit... My headunit (Alpine 7998r Phantomface) can go all the way to full without audible distortion. (Although some CDs are louder than others)

It has no internal amplifier though.

Peace

Tim

Yeah I have 6.5V pre outs and my Pioneer can go all the way with minimal distortion on quiet CD's. On some CD's it can only go to 35/40. Its all about being smart.

sam350 there are 3 ratings for a sub, WRMS, peak music and peak power ( max power ). WRMS is the advised power you should give to the sub that will cause minimal thermal destruction over time. This is usually about the power that you aim for.

Peak music is the maximum power the sub can take while playing music as varying signal strengths will cause problems. Playing at this input can put the driver beyond its limits and the manufacture can not guarantee its long term life.

Peak or Max power is the maximum load the driver can take from a sine wave and only for a few seconds. Your warranty will be void at this point.

This is why a sub like the Crossfire XT is 1000WRMS nominal, 2000WRMS peak music and 4000WRMS in bursts. My Boston G5 is rated at 450WRMS yet Boston recommend running it off the GT-28. That is a minimum 700WRMS @ 4ohm and 1350WRMS @ 2ohm... go figure?

that illustrates you better off over powering than under powering which i have seen on countless car audio forums.

the 7998r has no internal amp,just preouts hence low internal distortion. The hard work is all done by the amps. Good unit for sq but not practical for everyone.