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Discussion Starter · #1 ·
Hi,

After having some advice recently, I have now decided to use my sub for music as well as movies. I therefore re-run REW to get the most flattest response I could.

With reference to the graph, the kit used is a Sunfire HRS12" sub, B&W803D main L&R, and an antimode 8033. Xover is as 60hz, (including centre and rears). Without the antimode the room suffers a huge 15db peak at around 30hz?

I would like to know what your thoughts are on the graph please, and whether it is worth tweaking further? I am a slight novice re REW, but not adverse to learning:D

The sub is currently placed in a room 4.7mx3.3m, and situated at front wall, between centre and right speaker.

If anything, I would like to up the 40-60hz range, but have tried phase and distance settings but run out of any more improvements? This is where I start to become fustrated and lose the plot......:hissyfit:

The processor is rotel and does not have any form of EQ etc. The result below is from just pure relentless positioning and the antimode 8033.

Thank you for looking.

Regards

David
 

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Discussion Starter · #5 ·
Thanks.

I just assumed that the 'punch' is around that region, and that if I could get it a few db higher it should more evident? If you think its a pretty good response then that puts my mind at rest really......

I have managed to drop that 150hz peak slightly with positioning the mains, but lost the graph, but also the lower FR started to suffer slightly. Would you have any suggestions on this, maybe room treatment?

Bottom line is that im a noob who's looking for some reassurance that im not missing out too much musically re my graph?

Thanks!
 

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Not a bad response really, but why is it dropping off so much after 200Hz?
 

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Discussion Starter · #8 ·
Thanks for the link. Ill take a closer look later!

As far as the drop off after 200hz, the sweep is set at 250hz max, would this be the cause? Other than that im not sure? Should I set the sweep higher?

My laptop died a few days ago, so after buying a new one yesterday, im currently getting to grips with this new windows 7 business and trying to re install REW and calibrate everything etc?

Ive yet to set the parameters for REW, let alone do a new sweep. Should hopefully have a play around tonight?

If there are any suggestions please tell me!:dontknow:

So the consensus is that the graph is not bad? Good news then!

Thanks.

David
 

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That is a fairly good response David :T and the mains are adding in the 150hz region as they are very capable speakers but with some slight adjustments in positioning may help, boosting is generally not advisable with cuts being the preferred method and that is after you have found the best location for the sub in the beginning.

BTW - nice to see you over here :wave:
 

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Have you tried the LIFT25 and LIFT35 features on the antimode to see if that modifies the sound to your liking? You could also try simply increasing the volume on the subwoofer maybe 3dB?
 

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Have you tried the LIFT25 and LIFT35 features on the antimode to see if that modifies the sound to your liking? You could also try simply increasing the volume on the subwoofer maybe 3dB?
Yep, that's definitely worth a go.

Or you could try Wayne's house curve. (again you will need to search for it, Oh and you need a BFD)
 

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As far as the drop off after 200hz, the sweep is set at 250hz max, would this be the cause? Other than that im not sure? Should I set the sweep higher?
That shouldn't have that effect. A quick guess might be that you're mains weren't actually running during the sweep, and the sub ws running without the xover engaged, in other words it looks like it could be the top end of the sub's natural response, but that's just a guess.

You could try running a longer sweep, and if the graph comes back up at higher freqs then you know it's a "real" acoustic effect.
 

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Discussion Starter · #13 ·
That is a fairly good response David and the mains are adding in the 150hz region as they are very capable speakers but with some slight adjustments in positioning may help, boosting is generally not advisable with cuts being the preferred method and that is after you have found the best location for the sub in the beginning.
Great, this is basically what I was seeking, just some reassurance that im going in the right direction. Good to speak to you again, its a small world is the AV one!:bigsmile:

I did try the LIFT options, but they just seemed to excacerbate the rooms 35hz peak. It was to my liking, as it gave me 'more' bass at the bottom end, but I thought the whole point was to acheive a flat response, given the capabilities of the kit???

This then brings me on to a few questions, if I may ask for some further advice?

1) My response drops off at around 18hz, the sub is rated from 18hz onwards. Should I be happy with this, or should I corner load the sub (as per antimode recommendations) to use the room's natural own gain for better LF extension?

2) Should we always aim for a flat response, because after doing some reading I came across the house curve method. I havent completely got the idea yet, but have half a clue! and do I really need a BFD to achieve a house curve?

Bass is pretty good, at around ref level, which borders on uncomfortable SPL levels. Im assuming a house curve gives you that better bass feel through low to high SPL levels. I cannot get my head around this, where we should try to achieve a flat response, but a house curve it totally acceptable:huh:

I know I need to read into this myself, but do others here have their views on house curve vs flat response, and in what scenario what you apply either?

I do find all of this very interesting btw:coocoo::T

Thanks all!

David
 

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Discussion Starter · #14 ·
That shouldn't have that effect. A quick guess might be that you're mains weren't actually running during the sweep, and the sub ws running without the xover engaged, in other words it looks like it could be the top end of the sub's natural response, but that's just a guess.

You could try running a longer sweep, and if the graph comes back up at higher freqs then you know it's a "real" acoustic effect
The mains were definitately running? Does it matter if you use the Sub cal tone or speaker cal tone when running the sweep? It was set as full range in the settings menu?

When you say longer sweeps, am I assuming more runs, or at a greater frequency range?

Sorry!:dontknow:

Thanks
 

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The mains were definitately running? Does it matter if you use the Sub cal tone or speaker cal tone when running the sweep? It was set as full range in the settings menu?

When you say longer sweeps, am I assuming more runs, or at a greater frequency range?

Sorry!:dontknow:

Thanks
No, the sweep is separate from the cal tones. When I say a longer sweep, I mean a greater frequency range.
If we see the grph come back up, then what we see is just a dip... if it doesn't come back soon, then something's wrong.
 

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The difference between desiring flat vs house curve response is largely personal preference.
 

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Discussion Starter · #18 ·
That answers my question then.....!

Seen as it has taken me so long to achieve this reasonably flat response, I think i'll try living with it for a while before tweaking again? The sound is certainly different.

Bass is quite dry and tight, tending to sound more like thuds/bangs rather than booms and rumbles. Im also happy that there is not so much apparent ringing at the listening position, it was making me very uncomfortable. The bass during films now have that 'who's knocking outside' sensation, but not so much of the chair shaking rumble I used to experience?

Its the strange feeling if something missing from the bottom end, and possibly a lack of real sub bass as the sub is now placed mid wall. Originally it was corner placed, with antimode, with no final eq'ing, so god knows what the response was like. Probably a huge peak from sub 18hz to 40hz?

All I want to acheive is to hear what the director intended, but with options of house curves/flat responses etc, its just confusing me more?
 

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Many years ago when I was using a BFD for EQ I did use a house curve as my preferred option over a flat response, but now with my current sub and set up I do prefer a flat response with the sub approx 4-5db louder when setting up with an SPL meter.
 

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Discussion Starter · #20 ·
Many years ago when I was using a BFD for EQ I did use a house curve as my preferred option over a flat response, but now with my current sub and set up I do prefer a flat response with the sub approx 4-5db louder when setting up with an SPL meter.
I feel this is where I become confused? If I were to measure my REW flat response graph, using an spl meter, then my sub averages around 1-2db's lower than the mains, centre and rears.

If I were to up the db level on the sub, then surely the flat response would be lost, negating all the hard work?

Or am I wrong?
 
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