Filter Tasks - Match Range Question

[HuibertBoon]

About EQ>Filter Tasks> Match Range ...


The manual states "The Match Range defines the frequency span over which REW attempts to match the target response, and within which filters will be assigned."
That would mean that you select the freq-range of the speaker you've set in the Target type So: 20-20K for Fullrange, 80-22K for basslimited, 20-200Hz for Subwoofer, based on the specifications of the speakermodel. (No need to calculate filters outside the frequencyrange of the speaker...)

But then the manual continues with the following:
"REW can apply filters anywhere across the band, but it is usually best to limit filters to low frequencies (less than 200 Hz or so) unless you are compensating for some general characteristic in the speakers (an example might be a dip in the mid range or a bit too much HF) - that is using EQ as a fancy tone control."

Does this mean that the term 'Filter' is used in 2 different meanings: as only LP, LS, HP and HS under Match Range, but as all type of filters (including PK and Notch) like under 'EQ filters' and 'Allow narrow filters below 200Hz'?

 

[Wayne A. Pflughaupt]

First, welcome to the Forum!

That would mean that you select the freq-range of the speaker you've set in the Target type So: 20-20K for Fullrange, 80-22K for basslimited, 20-200Hz for Subwoofer, based on the specifications of the speakermodel. (No need to calculate filters outside the frequencyrange of the speaker...)

That’s one way to do it. More typically I think people set it up for the range they’re interested in applying filters to.

Does this mean that the term 'Filter' is used in 2 different meanings: as only LP, LS, HP and HS under Match Range, but as all type of filters (including PK and Notch) like under 'EQ filters' and 'Allow narrow filters below 200Hz'?

Not entirely sure I understand what you’re asking. However LP, LS, PK, etc. are all filters – just different types for different purposes.

Regards,
Wayne

 

[JStewart]

Does this mean that the term 'Filter' is used in 2 different meanings: as only LP, LS, HP and HS under Match Range, but as all type of filters (including PK and Notch) like under 'EQ filters' and 'Allow narrow filters below 200Hz'?

As Wayne said, they are all just filters.

The statement “but it is usually best to limit filters to low frequencies (less than 200 Hz or so)” is guidance based the research of Dr. Floyd Toole and others. When you equalize low frequencies you are adjusting for room effects. For high frequencies you are changing the speaker and perhaps not in a good way. A tone control or high shelf has a different effect from peq filters in that it effects the frequency range equally and therefore doesn’t change the loudspeakers natural response. To definitively know when peq will work or not for high frequencies much more data is needed than a REW sweep at the listening position provides.

Of course then there comes the matter of preference. What one likes for themself is always correct. But the research suggests to start with the guidance in REW as it will most likely yield the best result for most listeners.

Has this answered your question?

 

[HuibertBoon]

Thanks for both your replies; this has more or less answered my question.

Some people would say that the difference between filters and equalisers is that filters can only attenuate, equalisers can both boost and attenuate. So only HP, LP, BP and Notch are real filters, not equalisers, and a peakfilter is not a filter but a (parametric) equaliser. 'shelves' fall a bit between the cracks of this definition, since even purists call these 'shelving filters', though they can also boost. Others are less strict or puristic about this and use the term EQ, Equaliser and filter more or less interchangable depending on the purpose..

Since I didn't know in which of these interpretations applied to REW, I wondered if setting the 'Match Range' to a max of 200 for the 'filters' meant that it only applied to the HP/LS filters and not to the configurable parametric equalisers. In other words: I interpreted it as: preferably set the Match Range to 200max, so the HP and LS filters are only applied for frequencies from 20-200Hz, and that REW would not generate HP/LS, but only PKs and such for everything above 200Hz.

But I undertand now that the idea is instead: preferably use EQ only for room correction at low frequencies, because above 200Hz you're correcting speakerperformance instead of room performance.

That being said, I do need some speakercorrection, since I am forced to use different speakermodels in a 9.1.6 setup and although my room is fairly well-treated, even the same-model speakers need some eq to match eachother (a bit) better.

Which leads to a following issue, with 2 questions:
I use an Antelope Galaxy 32 audiointerface, which has the following 16-band eq-per-channel posiibilities:
EQ 1: HP/LS
EQ 2 -15: PK
EQ 16: LP/HS

Since this EQ is not listed in the Manufaturer/model-lis of REWt, I need to use the generic eq.

My 2 questions are:
1. In stead of a flat target for all speakers, can I use a frequency reponse curve from (one of the) main speakers, as a target for the surround- and top-speakers.
In that case I would indeed just use a 'Match Range' up to 200 Hz for the main speakers and a match range up to 20kHz for the surround and topspeakers to follow the main speakers more closely.
2. Is there a possibility to create a generic eq that matches the eq-setup in the Galaxy32 or - as a request in stead of a question -
can this eq be added to the manufaturer/model list?

Best regards and thanks again.
Huibert

 

[JStewart]

1. In stead of a flat target for all speakers, can I use a frequency reponse curve from (one of the) main speakers, as a target for the surround- and top-speakers.

Sure. Export the response, presumably after its Eq'd as desired, and then import as a house curve in the EQ Settings section of REW. Check or uncheck the box for Add Room Curve as desired.

Is there a possibility to create a generic eq that matches the eq-setup in the Galaxy32

You can manually set filters and when REW matches range it will take the manually configured filters into account leaving them unchanged and calculating automatic filters to complete the task.
Here I've done an example. A manual High Shelf has been set and as an example 9 bands of PEQ are configured as automatic.

This is the result. As you can see, although only the range of 35 to 200Hz was corrected, the HS filter was left in place. Manual filters will be left in place within the corrected range also. More specifics are in the REW help.

Try it if you wish. Then if you run into a question let us know.