First time user - mixed results

[lovingdvd]

Hello - well I got all the pieces in place and go up and running quite smoothly with REW. What a fantastic product! Hats off to all those that contribute to its development and support. The help files are exceptional and it made for a very smooth setup and configuration.

Its late so I'll spare some detail for now, but I had some mixed results so I'd like to please get some clarifications:

I measured for only the sub. Target was 75dB, xo 80hz. I used the Find Peaks and Optimize very easily and it flattened out a good bit of the major peak issue I was having!

However I am unclear what to do about the dips. For instance I have a dip at 60hz. I was able to clear it up by using +6dB gain 4 wide. The curve now looks nice. However I am concerned about headroom and clipping issues because the manual says not to go over 3dB gain for filling in dips.

I play my system at fairly low levels most of the time, and only occassionally start to crank it up. But even in those cases I never really blast it. Point is that I know the sub can play and handle much larger volumes than I ever push to it. So in that case am I safe using this level of gain?

The other question I had is that I wound up using all 12 filters because I had various small gaps to lower (about -2 to -5dB) and a handful of dips to raise (+3 or so except for that one +6 I already mentioned). This made for a rather choppy line (all +/- about 2-3dB from 75db).

Is there a way I could have it smooth this out? I used the Optimize function but apparently that only smooths out the AUTO filters, whereas these I added were manual. Is there a way I can tell REW 'hey these are filters I want you to consider in your optimization' and have it smooth over my manual ones as well? If not how does once achieve a more smooth curve if they have several small dips and peaks to manually take care of?

OK so after doing just the sub I turned my attention to calibrating with the L/R fronts added in and set to full range Full Range. This is where things went down hill.

In this mode I had a very choppy spikes for dips and peaks from 30-100hz (and up). Lots of zig-zags. I don't know how to begin to smooth that over. It took out some peaks but I'm left with a ton of big dips. When I measured my L/R along without the subs and choose Base Limited I saw that these speakers contribute a lot of bass (as they should - they are rated down to 32hz). I am really surprised to hear just how much bass is coming out of these speakers below the 80hz crossover, and I verified that my Yamaha receiver is set to xo at 80hz.

I'm tempted to just equalize the sub alone knowing that it will be smooth and not worry about how the sub and fronts do together. However I have a feeling that is the wrong approach.

Also as a side note - what is one supposed to do if they have a significant dip. Everything I read says don't crank up the gain too much. But say someone has a -10dB dip? I'm thinking that in this case you can define the target -10dB lower, and then flatten everything else out. Then just crank up the sub to get it balanced with the rest of the system again. But not sure if that is the right approach.

For instance in my case where I had that -6dB dip, is there an easy way to take out 6dB from everything else and then not have to raise the dip? I'm very confused about this.

Thanks again!

[lovingdvd]

BTW - I just wanted to add that I have not yet tried any of the EQ filters in the BFD - just working within the REW software and its estimated results. Perhaps actual results will be close but a bit smoother and these little dips/peaks I referred to in my last post will be smoothed.

At any rate I plan to get these programmed into the BFD tomorrow. Because the MIDI doesn't work I didn't have a chance to program it in yet, as I'll need to research how to do that tomorrow.

[terry j]

"For instance in my case where I had that -6dB dip, is there an easy way to take out 6dB from everything else and then not have to raise the dip? I'm very confused about this."

For sure, boosting the entire response by 6db then cutting everything else back around the dip is a totally valid and workable way to go, and is usually the way I do it. Of course that only applies to the sub, guess it's a bit trickier if it's the mains that are causing it!

You didn't mention how 'sharp' the dips were, the sharper they are the less you need to worry about them.

In any case, more intelligent help is probably on it's way!! ha ha. Just as an afterthought, always test the results of any boost you do, if it doesn't respond to the boost then get rid of it quick as it's likely that no amount of boost will help in that situation.

As always, trust your ears and if it doesn't sound like it is struggling then it is probably OK.

[Ivaols]

lovingdvd wrote:

OK so after doing just the sub I turned my attention to calibrating with the L/R fronts added in and set to full range Full Range. This is where things went down hill.

I'm tempted to just equalize the sub alone knowing that it will be smooth and not worry about how the sub and fronts do together. However I have a feeling that is the wrong approach.

Thanks again!

Hi,

1: try setting the L/R fronts to NOT play anything under 80 HZ. This will give your speakers and your receiver more headroom, and will probably remove a lot of the (gain/phase) problems below 80hz.

2: Your feeling is correct, after all you do listen to front speakers and sub at the same time.

[lovingdvd]

terry j wrote:

For sure, boosting the entire response by 6db then cutting everything else back around the dip is a totally valid and workable way to go, and is usually the way I do it. Of course that only applies to the sub, guess it's a bit trickier if it's the mains that are causing it!

Mainly concerned with just the sub at the moment. How do I go about boosting the entire repsonse by 6dB and then cutting everything else back? Do I simply turn up the sub? Will REW then take care of the filters to flatten everything back to the target? I ask because this will not really be a peak for much of the range - instead it'll be a range that's about 6dB too high.

You didn't mention how 'sharp' the dips were, the sharper they are the less you need to worry about them.

Pretty sharp, like zig-zags.

In any case, more intelligent help is probably on it's way!! ha ha.

Thanks I look forward to hearing from the guys on all this but certainly your input has been very helpful too!

[lovingdvd]

Ivaols wrote:

Hi,

1: try setting the L/R fronts to NOT play anything under 80 HZ. This will give your speakers and your receiver more headroom, and will probably remove a lot of the (gain/phase) problems below 80hz.

Is this a common feature in receivers? I don't think there is any way I can tell my Yamaha RX-V1400 to not play anything below a certain freq like 80hz. I have them set to Small, and have the xo at 80hz, but it would be great to have it cut the lows off sharper if anything.

It does have an EQ that I could probably use to set 60hz very low and maybe 80hz too. But if I engage its graphic EQ then I cannot use its parametric EQ auto-calibration, and I need that for it to balance the high end (unrelated to the sub).

[lovingdvd]

Here's an oddity I was also hitting I'd like some feedback on...

When I did the Check Levels from the Sound card options it said my input level was good like -18dB. However when I press the Check Levels button on the Measurement window before taking a measurement it said it was too low, like -30ish.

So I then used the option to increase the level from -12 to -9. Then the measurement Check Levels button said the level was ok. But then the problem was that my receiver was no longer putting out 75dB, it was putting out something more.

So then I'd lower the receiver volume so I was back to 75dB, but then the Measurement Check Levels button again would say it was too low. So I was caught in this cycle.

Eventually somehow or another I seemed to manage to get this straight while using the -12 setting. Not sure how I did this though and am wondering what to do the next time this happens. Thanks.

[brucek]

Mainly concerned with just the sub at the moment. How do I go about boosting the entire repsonse by 6dB and then cutting everything else back? Do I simply turn up the sub?

Yes, but the sub has to have that headroom. You'd be far better to post your graph so we can see it.

Is this a common feature in receivers? I don't think there is any way I can tell my Yamaha RX-V1400 to not play anything below a certain freq like 80hz. I have them set to Small, and have the xo at 80hz, but it would be great to have it cut the lows off sharper if anything.

Yes, most receivers allow a different crossover than 80Hz. If yours is fixed at 80Hz that is fine.

Is there a way I could have it smooth this out? I used the Optimize function but apparently that only smooths out the AUTO filters, whereas these I added were manual. Is there a way I can tell REW 'hey these are filters I want you to consider in your optimization' and have it smooth over my manual ones as well? If not how does once achieve a more smooth curve if they have several small dips and peaks to manually take care of?

REW does what you ask. The Help file says:

"The filter settings can be manually adjusted to improve the correction, typically adjusting the Q values and using Adjust PK Gains to readjust the gains to suit. The graph traces update as the adjustments are made making the process fast and easy. Adjust PK Gains alters the gains of all Automatic filters to bring the response at their centre frequencies to the target level. Q is not altered."

So simply set a filter to MANual if you don't want it included or set it to AUTOmatic if you do want it included.



brucek

[lovingdvd]

brucek wrote:

Yes, but the sub has to have that headroom. You'd be far better to post your graph so we can see it.

Is it possible to post the mdat file so you can see everything including the filters?

Yes, most receivers allow a different crossover than 80Hz. If yours is fixed at 80Hz that is fine.

Mine definitely has variable xo. For instance I can move it up from 80hz, to say 90hz, 100hz, 110hz etc. I thought what Ivaols was saying was to set things so it does not play anything at all below the xo. Because of the slope that would mean setting the xo quite high. I'd like to get the xo point as high as possible. But my concern is localization of the sub. If I start sending say 90hz or more to the sub won't I risk localization?

REW does what you ask. The Help file says:

"The filter settings can be manually adjusted to improve the correction, typically adjusting the Q values and using Adjust PK Gains to readjust the gains to suit. The graph traces update as the adjustments are made making the process fast and easy. Adjust PK Gains alters the gains of all Automatic filters to bring the response at their centre frequencies to the target level. Q is not altered."

So simply set a filter to MANual if you don't want it included or set it to AUTOmatic if you do want it included.

brucek

Yes I had read that and tried setting mine to AUTO. However when I told it to optimize things after I added my manual one in it REMOVED all my manual entries. So I figured that in order for the entries to "stick" manual entries must be set as Manual. Obviously I am missing something here? Thanks!

[brucek]

But my concern is localization of the sub. If I start sending say 90hz or more to the sub won't I risk localization?

Yes, leave it at 80Hz. You took what Ivaols said too literal. He meant set the xo at 80Hz.

Is it possible to post the mdat file so you can see everything including the filters?

Yea, you can just attach an mdat file just like you attach a pic. I'd rather see the pic too...

Obviously I am missing something here? Thanks!

Just play around. You'll get it..

brucek

[lovingdvd]

brucek wrote:

Yea, you can just attach an mdat file just like you attach a pic. I'd rather see the pic too...
brucek

Thanks. I've attached the files. Note that although the file type is .mdat, these are really .zip files of the .mdat. So after you download them please rename them from .mdat to .zip. I had to do this because the mdat files were about 780KB each so the forum wouldn't accept them because they were over 750kb.

I was under the impression that this file is mainly a project file and that once loaded you'll be able to see the graphs and recommended EQ settings and so forth. No? If not let me know what graph you want me to produce and I'll follow the guidelines for posting it.

Also when you have a chance please let me know about the auto vs. manual EQ filters question I have. In my last post I mentioned that when I set the filters I added with Auto and tell REW to optimize, REW removes my filters. This is why I did them as manual but would prefer it to take my "auto" as hints and do a better job with the EQ than I can do manually. Thanks again!

[brucek]

I was under the impression that this file is mainly a project file and that once loaded you'll be able to see the graphs and recommended EQ settings and so forth. No?

Well yeah, but that's kinda time consuming. I would rather you press the 'save as jpg' button on the REW graph and post it as an image as I've done below - then everyone can discuss....

Anyway, your response of the sub is easily BFD'd. I attached a quick set of filters where I only added one more than REW recommended and then optimized. Simply don't use manual. Make all filters AUTO. It works fine. You could just enter the filters I show into the BFD and it would clear up a lot, but it's better you play with it yourself. I attached the before and after picture of your sub.

The mains plus sub is another story. I don't see how that is your mains and sub together. It looks more like the mains only. If it's the mains plus sub, then where did the sub go. Look at the sub only and see what I mean. You'll have to sort that out.


SUB ONLY RAW MEASURE




FILTERED SUB



SUB + MAINS (I don't really think so??)




brucek

[lovingdvd]

brucek wrote:

Well yeah, but that's kinda time consuming. I would rather you press the 'save as jpg' button on the REW graph and post it as an image as I've done below - then everyone can discuss....

Makes sense - will do that in the future.

Anyway, your response of the sub is easily BFD'd. I attached a quick set of filters where I only added one more than REW recommended and then optimized. Simply don't use manual. Make all filters AUTO. It works fine.

I'm still confused about the Auto filters. I'll play with it some more and see what I can figure out. Perhaps I am not following the procedure correctly? Any idea what issue I may have been hitting where I was adding Auto filters, then telling it to optimize, and it was removing my filters I added?

What about the dip at 53hz? Should I add a manual filter to try bringing that up a few dB? Same for the smaller dips and peaks? For instance is it helpful at 20hz, 31hz and 37hz to add a narrow filter to bring these down a few dB? And perhaps push up 72hz a couple dB? I recall seeing graphs you've posted of your HSU and the line looks perfectly smooth around the target. Then again you are the master!

The mains plus sub is another story.
brucek

Yea I'm not sure what happened there. I was playing with lots of things back and forth and it was late. That likely was mains only. I'll work that out.

My plan from here is to first get the bass only equalized. Then I'll add the mains back in and see what it all measures together. From there I'll tweak it some more. Too bad I don't have any EQ control over the fronts for its bass. I could get limited control via its graphic EQ but then I'd lose its parametric EQ functions which I need for the high end.

[JohnM]

lovingdvd wrote:

Here's an oddity I was also hitting I'd like some feedback on...

When I did the Check Levels from the Sound card options it said my input level was good like -18dB. However when I press the Check Levels button on the Measurement window before taking a measurement it said it was too low, like -30ish.

So I then used the option to increase the level from -12 to -9. Then the measurement Check Levels button said the level was ok. But then the problem was that my receiver was no longer putting out 75dB, it was putting out something more.

So then I'd lower the receiver volume so I was back to 75dB, but then the Measurement Check Levels button again would say it was too low. So I was caught in this cycle.

Eventually somehow or another I seemed to manage to get this straight while using the -12 setting. Not sure how I did this though and am wondering what to do the next time this happens. Thanks.

What end frequency were you using? The levels check in the measurement window tests across the whole range you are set to measure, when measuring a sub that means the result gets lower as the end frequency goes higher. It operates differently to the levels setting on the soundcard settings to avoid having to select whether you using a sub or a main speaker (Bruce told me this would confuse people )

[brucek]

What about the dip at 53hz? Should I add a manual filter to try bringing that up a few dB? Same for the smaller dips and peaks? For instance is it helpful at 20hz, 31hz and 37hz to add a narrow filter to bring these down a few dB? And perhaps push up 72hz a couple dB?

A dB here or there isn't going to really matter. The fact is, if you move your microphone a few feet you can easily have a different spot where the response will move a few dB. The really important part is removing the large peaks that occur at room resonances. Yours was at 30Hz. That's taken care of. The rest is window dressing for people who like to push buttons - of which I am a charter member.

brucek

[brucek]

What end frequency were you using?

Yeah, I was going to answer that question John........just ran out of time.

He had an end frequency that was too high.....



lovingdvd, change your sweep range to have an end frquency of 200Hz in the Measurment panel pulldown...

brucek

[lovingdvd]

brucek wrote:

Yeah, I was going to answer that question John........just ran out of time.

He had an end frequency that was too high.....

Attachment 1875

lovingdvd, change your sweep range to have an end frquency of 200Hz in the Measurment panel pulldown...

brucek

Roger that - will do. This is to take care of the input level warning?

[brucek]

This is to take care of the input level warning?

Yes...........

[lovingdvd]

Great. Tonight I'll do some more experimenting and will put the filters into the BFD. Looking forward to hearing my sub with a flat response (the peaks I have really make it sound pretty lousy as-is) and then I'll play with the house curve. I'll report back on how it goes. Thanks again for all the help.

[cyberbri]

You should DEFINITELY think about adding some bass traps to your room. Not only will it smooth out the response, it gets rid of a lot of ringing and boominess. You may not even notice any, but once you hear how your sub sounds without that nastiness, you'll never go back.

For example, here's how my in-room response looks (sub+mains) with a few bass traps:


I was able to smooth it out to this with these filters:

Freq BW Cut/Gain
74Hz 6 -13
45Hz 8 -7
66Hz 2 -4
54Hz 8 +4
37Hz 4 +4
53Hz 3 +2



Before I was using a ton of filters, 11-12, including a lot more boosts. I had similar results, but I like using less filters this way. Plus, with all the cuts I was using in the BFD, I had to turn the gain on the sub up a lot more - to 55-60% or so. There was a slight hum (presumably from the BFD and the extra connections), although it was only audible with no sound in the room and if I was within 4' from the sub. Being able to turn the gain on the sub down and just amplify a higher signal really toned down the hum as well.

It takes a lot of experimenting. I've probably "redone" my filters 5~6 times now. Now I'm really satisfied with my results and I probably will leave them like this for a long time. With bass traps first, then with the BFD, listening to the "it's cold in here" scene from The Haunting went from "scared, but for the safety of my sub," to controlled, tight bass, hearing every detail and knock and rumble and texture.

[lovingdvd]

Thanks for the advice. I will have to look into adding traps.

You mention using cuts and it brings me back to something I don't think I got answered yet. Looking at the second chart shown in the post above (http://www.hometheatershack.com/foru...31-post12.html ) let's say I didn't want to add a gain to 53hz. But rather, I wanted to cut everything down instead in order to flatten things out without having to use a gain. How does one go about such a think?

[cyberbri]

First, to see if it's a dip and/or if the other frequencies are just being boosted by the room - vs it being a null, try additional sweeps to see if the volume increases/decreases the same as the rest of the graph. If it won't get any louder when you run the sweep at louder volumes, or if it only goes up a bit while the rest goes up a lot, that's tough.

But if you want to use filters to "cut" everything to the level of the lowest, do a sweep and get that lowest level around 70~75dB. Then set the "target level" to whatever dB level that range is in, and use "Find Peaks," "Add Filters," and "Optimize Filters." Be sure to check the before/after for the filters, because at least for me the end result didn't always come out like REW predicted it would.

But don't worry about a dip that deep at 53Hz. It's probably a null if it's that deep. Aim for the level of the mid-60s there, or about 72dB on that graph. Fixing a null like that requires moving the sub and/or the couch, and bass traps could possibly help with that as well.



Also, you may find that you prefer to leave some kind of house curve on the low end, because you need more dB in the 20s and lower for it to be audible anyway. If you look at my graph:

I cut down on the rise at the bottom end, but not too much. Music won't usually dig this deep, so the impact is there for movies but it doesn't make music sound too bottom-heavy.

[lovingdvd]

Thanks. My listening is almost 100% movies so I'll definitely be experimenting with house curves once I get a handle on the basic calibration.

Thanks for the tip about the dip - that's just what I'll do. I'll turn my volume up say 5dB and run the sweep again and see how much the dip comes up.

Just to make sure i have this basic principle right - it's ok to use cuts as heavy as you need (negative dBs) to get a curve with no impact (other than having to turn the sub louder). But ideally one should not add any gain beyond 3dB because doing so requires twice the power?

So in other words, everyone is in agreement that to fill a dip (assuming it is fillable and not a null) its far better to use greater cuts almost across the board, than to fill a single dip with say 6dB correct?

[cyberbri]

If it's just one dip and the rest is pretty flat, try adding 3dB. A 3dB dip isn't as bad as a 6dB dip. And that would probably be easier than trying to cut every other frequency and shape it to be flat.


But a lot depends on your "target" level, what dB you aim for when you experiment with filters in REW.

Here's a case in point, from my thread over here:
http://www.hometheatershack.com/foru...igh-freqs.html

Here's my sub and mains, no BFD, just some bass traps:




Here's one attempt - with very good results, but using a lot of filters:


The filters I used to get there:
Freq BW Adjustment
24Hz 8 -3
30 10 -4
48.5 3 -5
40 6 -7
44.5 6 -12
53.25 3 +6
72.35 10 -16
83 6 -5
51 2 +4
89 2 +6
37.88 3 +3
100 4 -7
(some of these I added because when combined with the output of the mains I had some peaks I wanted to tame)

And here is my most recent attempt, which I think came out very well, with much fewer filters:


Filters used
Freq BW Cut/Gain
74Hz 6 -13
45Hz 8 -7
66Hz 2 -4
54Hz 8 +4
37Hz 4 +4
53Hz 3 +2

As you can see, I used cuts to bring down the big peaks, and a few small boosts to flatten it out. I could always add 3 more filters and do small 2~3dB cuts to smooth out the 60~75Hz range, but I didn't want to mess with it.

(ignore the null around 90Hz in the first and 3rd graph -- the middle/2nd graph was taken with my speakers in their original position, and after taking that I moved my speakers closer together and back a little so they're a little further away, and the 1st and 3rd graphs were taken with the new speaker position. That null is just from the sub + mains interaction. And that's why they look different above 100Hz)


One thing I didn't like about the previous attempt (2nd graph, lots of cuts) was that I had cut the levels so much I had to turn the gain on the sub way up. It was at about 55-60% and I could hear a hum coming from the sub if I got pretty close. With the most recent pass, much fewer cuts, I'm under 1/2 way on the gain on the sub. My HK receiver puts out a lot of voltage in the sub signal, so I had to turn it way down in the receiver so the signal wasn't clipping coming into the BFD. Originally, before BFD, the gain was at maybe 15% or so, or 1/2 way between 0 and the first tick on the sub gain.

[lovingdvd]

Looks great! I see what you mean. Regarding my dip, take a look at the second graph in this post: http://www.hometheatershack.com/foru...31-post12.html . Look around 53hz. That's about a good 6dB.

That could be a null that I can do nothing about (short of room treatments). So I'll try your recommendations as far as determining whether its is treatable with equalization.

Assuming so, based on that graph would you push it up 6dB, or bring everything else down instead, or maybe just bring it up 3dB and let it be short about 3dB?