Underpowered Sub?

[AgnessGP]

Hi All,

Been having discussion with volxstu regarding this but just want to rule one thing out (Stu, I know you said my amp should be okay but just want to check mate, its not that im not listening to you )

Am I underpowering my sub as, although I've learnt a lot, im still a bit unsure on power ratings etc.

My AMP ratings:
Output power in 2ohm = 90w RMS
Output Power in 4 ohm = 65w RMS

Mono Sub Channel 2 ohm = 280 w (no rms stated)
Mono sub channel 4 ohm = 170 W RMS.

http://dls.se/en/car/prod.html?produkt=en_102

This is currently powering:

Hertz ESK 165:
Power = 200 w Peak, 100 w continuoues

http://www.caraudiodirect.co.uk/hertz-energy-esk-165-3.html

DLS Rw10i:
Power = 250w rms

http://dls.se/en/car/prod.html?produkt=en_807

To me, that would look underpowered but unsure tbh.

The reason for this is that, after amping the speakers, the sub sounds much poorer than previous and just want to rule this out before making the setting changes stu has suggested.

Thanks in advance,

Sam

 

[PuntoHowTo]

Firstly all figures on that website are apparently stated in RMS. So basically you have an Amp some components and a sub

your amp is putting out 2 channels at 65W RMS 4ohm
your components need 2 channels at 100W RMS 4 ohm

your Amp has a Sub channel 280W RMS 2ohm
your Sub required a channel 250W RMS 2ohm

so basically your amp can deliver more power than your sub needs and the components can handle more power than your sub can supply I personally don't see a problem with any of these figures they are all pretty close your not going to risk blowing your components and the difference between the amp and the sub is fairly minimal personally i would prefer to under power a sub then you can be sure of its longevity but its its 30w RMS difference

without going in to complexities these are not figures set in stone you don't need to match a 50w speaker to a 50w amp and even if you did they can still sound crap. so if Stu has given you some tweaks to make to the Sub then i would follow his advice, I don't think it has anything to do with the amp because if anything it is capable of over powering your sub

 

[volxstu]

i would prefer to under power a sub then you can be sure of its longevity but its its 30w RMS difference

Never do this. Power doesnt kill speakers, distortion does.
Under powering is more likely to result in distortion and killing speakers. I always try to over power my speakers and make sure that im sending a clean signal. Its easier to get a clean signal with too much power as your not trying to set the gains to their limit to get the required volume.

Sam i will finish writing the things to try at lunch. I promise lol.

 

[AgnessGP]

Okay this rules out the amp, thanks @AndyRKett

Stu: Dont worry about it mate, any help you give is appreciated.

Just gonna get a pic of something if I can, I think the connections behind the stereo are a bit too tight and might be the culprit. If this is the cause, your suggestions are not wasted Stu as it can only make it sound better. If this is the cause though, I do apologise for not checking this first

 

[AgnessGP]

Right iv done some testing. I unplugged the sub to see if it made a difference and it appears the bass is coming from the front speakers only.

When setting the balance to all rears, no bass exists even with the sub plugged in.

So i checked the connections:



As you can see, the silver sub connection has no room to fit properly at all, however, i dont think this would stop the signal completely.

 

[volxstu]

Has the head unit got a setting where you have to turn the SW on?

This is where i have got so far.
No 1
This is your High Pass Filter. This will cut off any frequencies below the number that you have it set to. In this case it looks to be around 105hz. I would normally start at 56 and listen to what sounds best between there and 70hz but at a guess 56 should be ok.
Doing it on the amp may give you a little more control but for now i would just set No 1 to 50 on the amp and then change it to 56 on your head unit. Thats obviously the HPF setting that you said is off the other day. Then you can flick either way a bit and whilst in the car and listen to the differences.

 

[AgnessGP]

excellent mate will try this as soon as the sub shows sign of life. Yes I do have an option on the HU to turn it off and on...and it does work as tried it out previous to amping speakers.

However, even with the sub on, it's not producing anything. If i go into the boot whilst music is on there's no sign of life.

All connections appear okay, both HU side and AMP side.

 

[volxstu]

Right so i will leave the settings thing for a Minute.
Its normally something very simple. Go back to the very basics. Testing after each step.
1:- Swap the RCA's around, so that the ones that are doing the front speakers signal are on the Sub signal. Then if one of the RCA's is the issue the sub will work but the speakers wont. Then leave them swapped. That way the right angle ones will face up in that space that you have clear on the head unit rather than facing down at the Bottom making them liable to issues.
2:- Check that the Sub is connected on the outside of the box.
3: Check that the sub is connected to the amp and correctly.
4:- Check that the Sub is connected in the box. Both at the sub and the box connection.

 

[AgnessGP]

Right. Iv put sub rca in front speakers and front speakers in sub. Sub worked but speakers didnt. Its good to know sub works though.

What now though..does this mean rca connection on stereo is broke?

Edit: put front speakers in rear rca of HU. Oviously the balance is messed up but itworks. Should i just leave it like this?

 

[volxstu]

That should be fine. The Fader should be on 0 anyway. You can reduce the volume of either sub and speaker by adjusting the gain. Just remember once the gain is set do you don't get any distortion you can only adjust it so it go's quiter.

I'm just trying to visualise the pic of the amp you sent. Iirc it was only the crossover that needs sorting. Make sure that is done.
Oh and try the sub x-over at 60hz on the amp. See if that brings out the mid bass in the front comes alive a bit more.
Set the balance to the left 1-3 clicks to the left. Listen to what seems to make the sound come from the middle of the dash.
What kind of EQ does the HU have. Can you write down the adjustable Frequency points?

 

[AgnessGP]

Okay, not sure what you mean by the 'cross over needs sorting' mate?

Oh and I can't adjust the HPF (high pass filter) on the HU to 56, they are only set numbers and the nearest is 50 or 63hz.

Also mate, not 100% on what you mean by 'only adjust so it's quieter', do you mean it's only sensible to adjust the gain to make them quiter rather than louder (to avoid distortion)?

Here is the graphic EQ from the HU:

 

[volxstu]

Yes until you get to understand tuning a little more it's best to only make the speakers quieter to avoid blowing them.
Especially considering it looks like that Powerful EQ is adding 3db of boost at some points. Iirc 3db doubles the volume.
Normally when you adjust the EQ you should put the frequencies that you don't want to be louder down. So for example if you want 400hz and 1khz to be up 1db then you put all of the others down by 1db. This will ensure that you are still sending a clean signal.

Try the HPF at 63 then. I do t think your mid bass will like 50hz.

Personally I would say put the EQ Flat. Give 2db boost to the 10khz and 1db 8khz then maybe 2db at 120hz and 1db either side. Try that and see if you get a less distorted sound and hopefully a raised stage height.

 

[AgnessGP]

Thanks Stu Ill mess around with it and see what sort of sound I can get.

Thanks for the help and explanations.

Think my dad is gonna open up the stereo and see if they are dead connections on the sub RCA...it's out of warranty now unfortunately.