Frequency cut off on sub

[anonymous-user]

Hi all,
Have recently bought a sub on ebay (rel t3). I haven't been able to do anything with it yet as it arrived damaged and am waiting on clamps and glue to fix it! I have been think about how to set it up and have come to the conclusion that I should be able to use a frequency sweep through the main speakers, note the point where the bass starts to trail off and set the cutoff on the sub slightly higher so it overlaps a bit. This seems like a very simple solution, which is why I am not convinced it will be the solution
Is this a reasonable way to set up a sub? Or have I missed something obvious?

[VEX]

Traditionally you check the specs of the Sub, but that is only really to get excited about how deep it goes! lol.

As for set ups, you would usually set your surround sound amp to be using SMALL LCR speakers regardless of the physical size and make sure it knows you have a subwoofer / LFE output.

This usually sets the amp up to run at around 120 or 80/90Mhz cut-off and below that the sound should be pushed out to LFE / Subwoofer. You should then be allowed to adjust it yourself (depending on the amp). Also depending on the L, C, R speakers you have. BookShelf ones would cut off around 120, FloorStandard usually have a greater range and cut-off around the 80/90 mark.

Then you have the fun and games of positioning and phase to get the sort of rumble you like.

Hope that helps and make sence.

V.

[Ambleton]

That depends. I have my REL StrataV sub hooked up via a high-level and turned off the sub output on my amp, and set front speakers to large on my amp. Whatever my stereo pair see, my sub sees. I found it a marked improvement from the LFE output.

The crossover setting and volume on the sub rather depends on your stereo pair. In a well set up system you shouldnt be able to tell the sub is there until its turned off!

The REL manuals go through a really comprehensive set up procedure. It doesnt take long but its worthwhile. The most important thing is getting the phasing right as it will totally kill it if its incorrect.

Edited by Ambleton on Tuesday 26th May 19:28

[anonymous-user]

Thanks for the replies, its for a stereo set up as opposed to surround sound, and have will be wiring it to the speaker terminals as Rel say this works much better. Hence why I'm guessing getting the cutoff right will be more important. I hadn't planned to measure the sweep as such, more just listen to the point where it starts to disappear. I have found a website that has a tone generator that goes from 10-200hz, with a voice that reads out the frequency every 10hz. It doesnt seem like the most scientific way to do it but figured it might be worth a shot. Failing that will start at 120hz as suggested and fine tune it from there.
Will check phasing too, I think it can only be one of 2 settings. I've set up dozens of stereo systems but this is the first time ive used a sub at home!

[sociopath]

I found the best way was to listen to music and decide what I liked, rather than listen to test tones. That is why you've got it anyway, to listen to music.

As it happens I preferred a decent amount of overlap, but spent a long time tweaking both the cut off frequency and the sub volume.

This was made easier by my decision to out the sub behind my listening position and not between the speakers, as I could tweak while listening. It also removes some of the room phase issues you could get if it's further away

[VEX]

Ok, stereo set up is different, sorry for the assumption.

Yes, definitely get several tracks you know really well and enjoy and bring the sub in to a level that enhances a track, then do the next track and decide if it needs adjusting up or down and so on through your tracks. Occasionally return to listen to the first few to make sure your not drifting away from the original rough set.

This is effectively how manual audio and video calibration is done.

V.

[StescoG66]

I did mine exactly as you said. Set roll off for the sub at about 10hz above roll off for the speakers.

I am of the opinion with 2 channel audio, you won’t notice when it’s on, but you will notice when it’s off. If you catch my drift......

[anonymous-user]

Awesome thankyou all Set up by ears it is, luckily have a lot of time on my hands at the moment so can spend as much time as I need to get it right. I like the idea of not knowing its there until its off, I'm not after shaking the place to bits, just aware of the lower frequencies missing from what I'm listening to. Clamps and glue should turn up today so hopefully be ready to set up tomorrow!

[VEX]

That is exactly how a sub should be, sound reinforcement rather than sound dominance.

Have fun.

[StescoG66]

You’ll find that a well integrated sub will make the mid range much more defined. Strange but worked for me,

For the record I set my sub up to roll off at 70Hz

[anonymous-user]

That would be a very welcome side effect as there definitely seem to be a small lack of mid in my system!