Subwoofer (help)...

[slim6y]

Ok, here it is... The question I have been waiting for and I'm turning to us herpers for advice...

I have just built a subbie for my home theatre.

It's a 10in speaker (which I got for nothing) and an unbranded 150WRMS Subwoofer Amplifier Module...

I've built it into a box (pretty temporary at the moment - but its doing the job) and it sounds great during movies and PS3 games.

It's hooked up to a Harmon Kardon AVR 347 Amplifier - through the 'Subwoofer' pre-amp output to the sub line in on the back of the module.

The problem was when my old subbie blew up (I think it over-heated) the amplifier stopped sending signals to it... I changed some of the settings but now I don't really know why it's not picking up when I play 2 channel music through the PS3....

I'm over-coming the possibility of over-heating again by incorporating two 12V computer fans on the heat sink of the module.

So... I have options for the subbie...

What channel SHOULD I use from the amp and what channel should I use in the back of the subbie?

What settings (ie LFE, Front, Centre, Left/Right Surround) should I use for the subbie from the amp???

I'm so confused - the 'auto' config doesn't put anything for the subbie... which sux...

I'm a little lost with this sort of technology because it seems so obsolete to be so difficult... There should be a setting that just says... 7.1 Surround.... And that's that!!!

Anyway - hopefully some tech on here knows what the hell I am on about and can help... don't make me go to geek forums please...

 

[driftoz]

i wouldnt think the sub would work at all if your only running 2channel on the ps3 as its only putting out L+R audio, and also how is the ps3 hooked upto the amp ? hdmi, optical, AV?

 

[slim6y]

PS3 to Amp - HDMI.

You're right - the sub won't work at two channel... but... I am sure there are ways around it... How do I get Smack My Female Dog Up by the Prodigy to make that bass thumping sound in two channel

What if I put the sub in the 'left' channel or the 'right'... What if I leave the sub in the sub out from the amp but change the settings???? These are the things i don't understand quite as much...

Right now it's set on LFE... but is that really the best? Doesn't my amp module already have a low pass filter on it? So why would I use another filter on the amp (which is built in?)

 

[The_Dreaded_Pets]

not so sure been along time since i played with home theatre lol but i know on my pc i can set 2.1 which is left right and sub can you do something like that on ur 5.1amp my ps3 is broken atm hdd died so i cant look through the settings on that for you.

otherwise runing in sterio u might be able to set the amp up to recieve in sterio but output in 5.1 since music is sterio it will usually play left right and sub with centre being skipped atlest thats in my experience.

 

[slim6y]

not so sure been along time since i played with home theatre lol but i know on my pc i can set 2.1 which is left right and sub can you do something like that on ur 5.1amp my ps3 is broken atm hdd died so i cant look through the settings on that for you.

otherwise runing in sterio u might be able to set the amp up to recieve in sterio but output in 5.1 since music is sterio it will usually play left right and sub with centre being skipped atlest thats in my experience.

I think you're right about the settings in the PS3 and the 7.1 amp... However, I did it once and it sounded awful haha... Will look at it again though

 

[Zoltag]

Right now it's set on LFE... but is that really the best? Doesn't my amp module already have a low pass filter on it? So why would I use another filter on the amp (which is built in?)

If the LPF on the amp module is a good filter (not all filters are born equal) and if your main amplifier is able to set a HPF low enough, then you could set it to a HPF and create an effective band pass filter to ensure your sub produces the cleanest sound.

If your PS3 is only sending 2 channel sound to the amp, you may not be able to do anything about it. However, you may be able to plug your left and right channels into crossovers, use them to split the high and low freq's, then combine the low frequency outputs and send them to the sub, whilst sending the high freq outputs to the speakers.

 

[slim6y]

If the LPF on the amp module is a good filter (not all filters are born equal) and if your main amplifier is able to set a HPF low enough, then you could set it to a HPF and create an effective band pass filter to ensure your sub produces the cleanest sound.

If your PS3 is only sending 2 channel sound to the amp, you may not be able to do anything about it. However, you may be able to plug your left and right channels into crossovers, use them to split the high and low freq's, then combine the low frequency outputs and send them to the sub, whilst sending the high freq outputs to the speakers.

That's the sort of thing I was talking about...

So - if I go from the 'left and right' pre-amp outs from the amp and into the 'left and right' ins on the subwoofer (is that correct?) - then set the amp to LFE left and right (I think I have that setting)... Will that work???

Can I run from left, right and subwoofer pre-amps to the subbie - or does that defeat the purpose?

 

[The_Dreaded_Pets]

nope that will make everything run in low pass .

in a car for example ur 4channel amp will run say the back speakers and a set of subs ch1 & 2 will usually be bridged and switched to LPF for the subs while ch 3 & 4 will run ur rear speakers or whatever on HPF then if ur runing splits u will have hpf going into the 6" woofer then have crosovers conected from that speaker which filters the super high frequency sounds into the tweeters also connected to the crossovers.

so in a home theater i guess u would have to do something simular unless ur amp or preamp has setings to automatically do it for you.

i would suggest droping into your nearest jaycar storeespecially if you have basic electronic knowledge talk to them about what you have and want to do. they may be able to help yopu or atlest sell you a LPF crossover.

the reason i mention haveing basic electronics knowledge is u pay bout 1 3rd of the price to buy kits and put them together yourself pretty easy diagrams to follow and golden rule is u have 3sec with the soldering iron on the circutboard before you burn it out (little leway but thats the rule i was tought).

fyi responce speakers from jaycar were rated in as being in the same catagory as speakers 4x there price the yr before last so they are good value for money the car amps are average there home theater gear i havnt had alot to do with.

hope this helps you out some more if i have trouble sleeping i will reply with more answers / ideas when i think of them haveing 4 kids in the house means those kindsa toys just get distroyed so i gave up on owning them along time ago haha

gl mick

 

[Zoltag]

The sort of thing you would need to do is like the attached image.

Now, the amp you have appears to be quite sophisticated. It may actually be able to perform this sort of setup internally, but I wouldnt know how to configure it.

 

[slim6y]

The sort of thing you would need to do is like the attached image.

Now, the amp you have appears to be quite sophisticated. It may actually be able to perform this sort of setup internally, but I wouldnt know how to configure it.

I will look into this I think... I'm sure the amp is quite sophisticated - but most people go for the auto-set-up options (of course)... Which I did do for quite some time myself... Who knows if it helps...

The auto-setup does these very loud hisses through the speakers to test their frequency ranges - very clever - but any good??? I don't know!

 

[The_Dreaded_Pets]

that diagram should work however becareful with the volume on the sub as in home theater systems the .1 (sub chanel) is 10% of the output that the other chanels have since home theater subs have a builtin amplyfier (as you stated yours haveing) wireing it up in parall with the L & R chanels then filtering the hpf n lpf through crosovers will send the full amount of power through your subwoofer which is aprox 10x more power then is needed to run it.

FYI best volume/quality is acheaved with 30-50% amp power - whatever your speakers are rated at (from memory car audio used to be my hobby before kids haha), this means you will not overwork your amp prolonging its life ect and your speakers shouldnt clipout due to underpower/overpowering meaning they also last longer dont get distorted and have nice crisp sound at all times.