Where EQ is used for a 'partially compensatable' issue such as an extraneous source, the issue is apparent and the loss of direct sound is also apparent. If you EQ until you hear a good balance, then you will measure a non smooth direct response.
Once you get your speakers 'out of the way', any extraneous EQ is an unwelcome distraction. Preference EQ is useful for hiding problems, or for teenagers who want to show off in their cars.
Are FIR filters the ideal way to go as regards any filtering that isn't correcting a resonance?
Boy am I glad to be able to make up my own mind. The concept I use needs EQ. No way around that. Quite frankly, almost any concept would need EQ. However some of that EQ is most often called a crossover, something that I don't have.
I don't see the need to downplay any way that is different from what someone has been doing for decades.
With FIR filters (or PEQ and a lot more work) you can EQ the direct sound without involving the room in that measurement. It's not that different from creating the desired response for a good crossover. But it can actually do a bit more than that.
What someone may call EQ for personal preference has often been done in the speaker design process. However in a concept where one "needs to paint" it's own frequency response one has the freedom to experiment with slight differences. And these tiny differences actually make differences in perception that can be quite surprising. One could call that EQ-ing for personal preference. I actually mimic the sound of speakers I have heard and loved in the past.
Just a touch of warmth. A slight deviation from neutral. Why? Because I've always loved that sound. And I could, so why shouldn't I....
No one needs to put a speaker in an enclosure and hope for the best. Shaping the response for best sound is quite possible these days (and has been done for ages with passive means) and is beneficial.
Just ask yourself the question when you want the sound to be right. When the first wave front hits you, or when room reflections or other influences had their shot to mess it up.
If people say: "don't EQ the direct sound", but still have passive components that shape their response to their desired curve, it makes no sense to me.
Just don't even try to EQ for reflections etc. and other room anomalies above the modal region. You'd be better off with multiple measurements that filter out these very local problems.
I decided to reduce those early reflections with passive means. As this works way better for me and is more predictable.
Yet, the fear for EQ-ing the direct wave front is beyond me, it's 2018 guys, wake up! Try something new! We aren't bending any laws of nature here.
By that I don't mean you have to alter your beliefs in any way, the theory still stands. But we can do a lot better than sticking a driver in a (well thought out) box and hope for the best these days.
I'm happy to be of a different opinion here, but I don't think that classifies me as a teenager in a car.
Look up the Beolab 90, Lexicon's new speaker, heck, everyone will be doing this in the near future.
I don't see the need to downplay any way that is different from what someone has been doing for decades.
With FIR filters (or PEQ and a lot more work) you can EQ the direct sound without involving the room in that measurement. It's not that different from creating the desired response for a good crossover. But it can actually do a bit more than that.
What someone may call EQ for personal preference has often been done in the speaker design process. However in a concept where one "needs to paint" it's own frequency response one has the freedom to experiment with slight differences. And these tiny differences actually make differences in perception that can be quite surprising. One could call that EQ-ing for personal preference. I actually mimic the sound of speakers I have heard and loved in the past.
Just a touch of warmth. A slight deviation from neutral. Why? Because I've always loved that sound. And I could, so why shouldn't I....
No one needs to put a speaker in an enclosure and hope for the best. Shaping the response for best sound is quite possible these days (and has been done for ages with passive means) and is beneficial.
Just ask yourself the question when you want the sound to be right. When the first wave front hits you, or when room reflections or other influences had their shot to mess it up.
If people say: "don't EQ the direct sound", but still have passive components that shape their response to their desired curve, it makes no sense to me.
Just don't even try to EQ for reflections etc. and other room anomalies above the modal region. You'd be better off with multiple measurements that filter out these very local problems.
I decided to reduce those early reflections with passive means. As this works way better for me and is more predictable.
Yet, the fear for EQ-ing the direct wave front is beyond me, it's 2018 guys, wake up! Try something new! We aren't bending any laws of nature here.
By that I don't mean you have to alter your beliefs in any way, the theory still stands. But we can do a lot better than sticking a driver in a (well thought out) box and hope for the best these days.
I'm happy to be of a different opinion here, but I don't think that classifies me as a teenager in a car.
Look up the Beolab 90, Lexicon's new speaker, heck, everyone will be doing this in the near future.
An externally hosted image should be here but it was not working when we last tested it.
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The main purpose of using FIR in room EQ is using direct to cancel reflection at a specific point. If this method is used for EQing at a specific listening point. It is reasonable to choose a range where quarter wave length is within the listening position variation range. But I would do this as icing on the cake. The speaker themselves need to perform well first.
Really I'm trying to focus on linear distortion, I've nothing against EQ. My understanding is that "normal" filtering can help flatten resonances and therefore distortions caused by those resonances, once that is done any other filtering would ideally be linear phase? I wondered if the room acts as a filter and whether that can be treated in the same way, apparently it's not that simple which is what I presumed.
I guess that that it's a problem with PA as with long distances the air responds differently to different frequencies. The coverage of the horns has to meet the dispersion of the particles of air with different grades of humidity etc.
Not arguing with that...
I don't do any EQ for particular songs, however after getting the speaker response where I want it, I do add a bit of personal preference.
Like I said, a touch of warmth noticeable on vocals. Add too much and it will muddy the sound of higher frequencies.
This could be called EQ-ing for preference. However if I overlay it on the listener preference graph as defined by JBL/Harmon I might not be all that different from other listeners at JBL:
While I arrived at that (red) curve by simply following my own preference over time, I now simply aim for the preferred listeners curve if I redo my EQ work. On top of this I still use mid/side EQ as discussed within this thread.
The listener subset used in that graph is a small one (11 listeners) however it is clear to see not everyone will have the same preference.
With arrays that need EQ you've got to start somewhere.
I started out mimicking basic known room curves to find my answers at first, but this got me nowhere. So I decided to EQ over time, listening to all kinds of music. Only making small changes at a time and living with that for a while. After measuring the curve I ended up with, it was impossible to deny the resemblance. My biggest deviation from this graph is in the mid/side EQ I use to get the most pleasing tonal balance all trough the stage from left and right compared to the phantom center. It does wonders for imaging and intelligibility too.
After all, we cannot deny we listen with two ears.
So what does this have to do with lowest distortion speaker drivers? Maybe not that much, however FIR EQ is used to get the most linear frequency response, throughout all of the frequency spectrum. That should answer part of scottjoplin's question.
EQ was used to linearize the response of the direct sound above the modal region, not to battle room effects there.
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Unless the speaker is used in a anechoic room or in the desert, the room remains the main contributor to a speaker sound. In terms of room placement, OP gets the edge for mimicking the natural omnidirectional dispersion of an instrument in the room.
One other important factor for a speaker is not only distortion (THD), it is also the ability to reduce IMD and obtain enough damping without muting small signals, otherwise it will sound dead with no detail in the music.
One other important factor for a speaker is not only distortion (THD), it is also the ability to reduce IMD and obtain enough damping without muting small signals, otherwise it will sound dead with no detail in the music.
If you plot THD referenced to the fundamental, you remove the issue of the fundamentals absolute amplitude (or bumpiness). So then applying EQ will move the amplitude up/down in areas but you do not change its %THD. It would be like changing the volume (within reason of course) and expecting %THD to change.
When using linear phase filters but not minimum phase as this could reintroduce distortions due to the resonances that have already been corrected?
This has surely got to be one of the biggest problems in sound reproduction.
A trumpet is certainly more directional than a violin. Yet when playing back sound through a speaker with a wide dispersion pattern (omni directional dipole style surely would be the worst for this) we try and produce the same level of trumpet sound towards the rear wall as out the front!
I would assume a narrower pattern speaker would not suffer from this so much as the aim is to deliver the on axis information only. This includes the reflections off the rear walls and room etc from the recoded venue, so that would mean the violin recording would include a delayed reflection sound, but the trumpet wouldn't.
From what I've tried (IIR, FIR, for amplitude and min phase) the distortion seems to be fixed by the system design (driver, enclosure ,box) and applying EQ never seems to make THD better.
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