Setting up a high level signal subwoofer

[timbo999]

Hey all!

I wanted to post in the HiFi section as my question is for stereo and a high level signal to a sub and just for music.

I've just kitted up with an Onkyo 509, Mission 733 floorstanders, 75C centre, Mordaunt Short big stand mounted for the rear and my MJ Acousticd Pro 50 mk2 with high level and LFE connections.

It might not be a true HiFi amp or setup, but I think it's amazing and certainly the best musical sound I've ever had.

So for music I already know that I don't want to use the LFE signal, using that sounds attrocious! In 2.1 with a crossover at 90Hz (the crossover could be lower but I don't like the bass of them leading at me when watching TV).

Now I'm trying to setup the high level line for the sub for music in pure 2.0 mode. I listen to drum and bass, the radio and real music like The XX and Coldplay type stuff. I know that the crossover on the sub should be set to around the lowest point my main speakers cut off. In my case my mains go down to 60Hz on paper so my sub setting should be around 60-70Hz. But how do I know the sound is right? And the volume? I know I shouldn't hear the sub, just music, and I think I'm getting there but not sure at all. I hav the volume on the sub almost at its lowest, literally just off minimum! And the higher the crossover I use the less sun volume I feel I need.

Now, should I have like a sub crossover of 90Hz and have some merging of frequencies coming from speakers and sub?

I have the gain around 60Hz and the bass is pretty strong. Around 50Hz and it's a little more pleasant but it might be missing out some frquencies. Maybe im just not aware of true sub bass till now? I guess I just need to find where I like the settings?

Ive used the sub before with some KEF iQ1 small bookshelf speakers and never got it to integrate well. Recently I tried it with my Mordaunt short small bookshelf speakers and my Yamaha micro hifi in the kitchen with the speakers above the cupboards and the bass seemed to sound amazing however i set the sub, on the hard tile floor. Maybe I'm just being critical now as this is my main system?

 

[MattSPL]

Do you have a cd with test tones? You ideally want to test your speakers and see how low they go in-room.

Then bear in mind that a subwoofers crossover is usually 12db/oct, meaning that whatever frequency you set the subs crossover at, it continues to produce frequencies above that, decreasing in level by 12db for every octave higher you go.

So, you will find that if you set your crossover at 50hz, you will still hear bass up and above 80hz from the sub. This can mess with your main speakers bass clarity.

You will probably find that your speakers have no problems playing 50hz in-room, maybe even 40hz. Once you know this figure, try setting the sub 10hz below that figure and go from there.

As you say, the lower the crossover, the more gain you can apply. This will give you more bass at the lower end, which is why you bought the sub in the first place. Having the crossover too high and the gain too low defeats the purpose of the subwoofer.

 

[timbo999]

Nice one for the reply!

I agree that I know little about all this, but you've just contradicted some things I thought I knew. Maybe I've been looking into AV forums and use a little too much and I needed some HiFi background thinking?

Its great to know that I can set the crossover at 60Hz and below and still get some bass above that, even if it is produced by the speakers, it will be quieter. I really never thought the sub would produce noise above its crossover!!!!!!!!

On the MJ acoustics website and setup guide, it suggests setting the high level at the same level as the lowest your speakers go, or around 10Hz higher as your speakers are unlikely to go as low as they say on paper. Saying this, it seems to be quite focused on home cinema despite the high level and LFE features and VERY detailed setup instructions.

Ive got some drum and bass on now, and some jungle, with the sub at 50Hz and the sound is MUCH more what I'd hoped for. The speakers are clearly doing all they are capable of and the sub is doing its own thing yet integrating really well. Not the settings I ever expected but awesome! I still have the gain right down, the speaker is only just moving but it's presence is there, I don want the house to shake, I want to just hear it all. I am listening at medium volumes, never very loud.

I don't have a setup CD no. Are they useful? What do you do with the settings when listening?

I also heard once that it's easier to get the settings right and integrate well when listening at high volumes, I guess this makes sense.

 

[MattSPL]

Its all a matter of personal preference, but i like to set the sub low. I usually end up setting a sub at 30hz or lower, depending on how big the speakers are, and if the sub can be set that low.

If you connect the sub and play some music with the speakers dissconnected, then you will hear the higher stuff that comes out the sub too.

A test cd with bass tones is very useful. You play tones with the sub off at different frequencies like 60hz, 50hz, 40hz, 30hz and 20hz. See how low your speakers can go, and how loud each frequency sounds compared to each other.
Your aim is to try and get the sub to just fill in the low bass that the speakers can't produce, or produce much quieter than the higher bass.

There are other methods of setting up a sub using a high pass filter to cut all frequecies below a certain point from your speakers, then feeding them to the sub. This is generally how the LFE channel works on an Av processor.

 

[timbo999]

Sounds like I'll be getting a test CD for sure!

Having a constant HZ coming out migh also make it easier to set the crossover and volume!?!

Youve been a great help and it's sounding good!

Im using the LFE signal with the amp crossover set at 80Hz. I don't really like all that bass coming through the speakers when watching the TV and films. With music it sounds completely different.

 

[MattSPL]

Glad its working out well for you. Its trial and error really until you have tried various settings and decided whats best. Just trust your ears really.

Cheers
Matt

 

[Big Chris]

Glad its working out well for you. Its trial and error really until you have tried various settings and decided whats best. Just trust your ears really.

Cheers
Matt

Totally agree.

You can have people chime in with "do this" & "do that", but I think you're better off having a play with levels and crossover frequencies yourself until you find a sound you're happy with..... That's what I did.

 

[timbo999]

My wife searched for a tune on her iPhone this mornin and found it on YouTube, so it went into the onkyo via USB. Straigh away the penny dropped and I searched for bass test tones on YouTube! Brilliant!

It seems my 733's go down to 50Hz and not much lower at all. On paper they state 60Hz and I'd have guessed they'd go no lower than 60-70. How wrong I was!

So, I'm still not sure about the sub the music. I'm setting the gain low still as the notes below 50Hz Alamogordo feel like vibrations rather than sound like notes. I think I might be happy with big floorstanders for music. I'll keep the sun on but low and just enjoy it for a while and see in the future about changes then. The quiet low notes will surely be benefiting the sound and giving more depth to the sound.

 

[MattSPL]

Just keep experimenting and try and get some high quality test tomes(i'm not sure what quality youtube is?).

I used to mess for a week non stop with a sub, then fiddle for another month on and off, then sometimes go back to it and turn the gain down a notch after a month or 2. I think this is why some people give up on subs or think they are too hard to integrate.

You basically need to teach yourself exactly how the sub behaves with different settings, then even if you buy a new sub, it will only take you 5 minutes to get it roughly right, then its just fine tuning from there.

Cheers
Matt

 

[timbo999]

I think the other thing for me, and no doubt many others, is understanding bass and sub bass values. Ive experienced a god few small stand mount speakers and I realise they don't have enough bass. My big bookshelf Mordaunt shorts have a nice amount of bass to them and a really nice, not too much bass, sound. My new "old" floorstanders put out far more bass and create a far different sound, a sound that is supposed to be there, but I never heard before as the speakers never produced that note. So, previously hearing a known tune, there'd be a thump, now theres a far deeper growl. I guess my taste in music has far more emphasis on the bass notes than many others. What I'm trying to say is, some speakers might go deeper than the listener actually wants to hear, I guess.

The beauty of my floorstanders is that they go down to 50Hz which is probably lower than I would deam necessary for me. If I want less bass I can change the crossover on my amp. If I want more, I simply switch the sub on.

And, floorstanders go FAR deeper than I ever expected. The bass in these bad boys is bordering on "brutal". When a note winds down through the octaves it makes me smile so big you wouldn't believe.

 

[MattSPL]

Getting used to your new sound with the speakers and sub will take a while, but you will get to explore your music collection all over again. I love getting new equipment for that reason.

I bet your drum & bass sounds very different than it used to now that you have more bass. I like drum and bass and all that kind of music too, Aphex twin is one of my favorite artists. Its not everybody's cup of tea, but i think he's a genius. Some of his music is a real test for hifi too.

Cheers
Matt

 

[timbo999]

Yeh, listening to some tunes is like re-living and re-loving them. Some notes last longer, change sound and go far deeper than I've heard before.

No doubt that drum and bass tests equipment and speakers. It drives through low notes and repeats that quite differently to many other types of music.

Live got massive appreciation for Aphex twin but they're not a favourite, ive just been into other and faster things. Faster stuff just makes me smile and dance. An awesome album is by D.Kay called Indicidu Soul, all live drum and bass on instruments, a work of art. Other loves are the likes of High Contrast and the rssr of the Hospital record label, The XX, The Gossip etx etc. stuff that goes deep and has some emotision gets me going. Just heard Alt+J on the radio and need to buy the album just to hear it at home!!! Can't wait.

 

[MattSPL]

Yeh, listening to some tunes is like re-living and re-loving them. Some notes last longer, change sound and go far deeper than I've heard before.

No doubt that drum and bass tests equipment and speakers. It drives through low notes and repeats that quite differently to many other types of music.

Live got massive appreciation for Aphex twin but they're not a favourite, ive just been into other and faster things. Faster stuff just makes me smile and dance. An awesome album is by D.Kay called Indicidu Soul, all live drum and bass on instruments, a work of art. Other loves are the likes of High Contrast and the rssr of the Hospital record label, The XX, The Gossip etx etc. stuff that goes deep and has some emotision gets me going. Just heard Alt+J on the radio and need to buy the album just to hear it at home!!! Can't wait.

Thanks for the D.Kay tip, i must get hold of that, sounds great.

Cheers
Matt