Linear phase EQ makes sense for recording and adjusting levels within the playback chain. But things get more complicated when correcting for dipole rolloff or diffraction. In those cases SPL changes because two similarly shaped waves arrive at the listening position at a time offset to each other. FFT time transforms that into an amplitude shift, which is reasonable so long as the two waves are not so far out of phase (time delayed) as to be heard separately. But, due to the time smearing involved, it's not clear to me if the phase shifts from warped phase EQ correcting the amplitude change will cancel the effective phase shift from the two waves interfering. So it's possible the residual phase error from applying linear phase EQ could be lower than that of warped phase EQ.
At this point a proof of pole-zero cancellations and phase responses eludes me. My guess is warped phase EQ is probably better in a mathematical or engineering sense but, even so, it may be linear phase EQ is percieved as higher quality.
I'm planning to do A/B measurements and listening tests between linear and warped phase EQ. But it'll be some time as I've to build some OB speakers to EQ first so I suspect this thread is likely to beat me to a conclusion.
Most of the phase shift is probably in the crossover so getting it to be linear phase is likely the main thing.
At this point a proof of pole-zero cancellations and phase responses eludes me. My guess is warped phase EQ is probably better in a mathematical or engineering sense but, even so, it may be linear phase EQ is percieved as higher quality.
I'm planning to do A/B measurements and listening tests between linear and warped phase EQ. But it'll be some time as I've to build some OB speakers to EQ first so I suspect this thread is likely to beat me to a conclusion.
Most of the phase shift is probably in the crossover so getting it to be linear phase is likely the main thing.Did you test Ozone by chance? It's not phase linear AFAIK, but the best sounding of all VST EQ i have tried.
I'd like to comment a bit on this - about "slam" and transient attack. Do you get that with high quaility headphones? I guess not.
I'm working on a 2x15" plus horn-loaded AMT right now (Beyma 15P80Nd and TPL-150H) in a large bass reflex cabinet with very large diameter ports. It sure has a LOT of attack and "slam", I've never heard anything like it. BUT - the tonal definition and clarity is FAR from a good dipole.
My conclusion is that the transient attack that some people want is just WRONG, its distortion.
Lets further analyse that "slam" :
Looking at it in *slow motion* it becomes:
sslLAMmmmmm
Meaning :
it first takes time to build up – than explodes in exaggeration – then it has a pretty long tail
I really love scientific research !
LOLMichael
Hi. Stig E. Im just chiming in
I'm a bit puzzled by this statement, because when i listen to this kind of artificial slam and punch though a transparent setup, it is quickly revealed as compression. In my oppinion it is only on low to midrange equipment that this method works.
For reference I'm talking about the Quad ESL's, Klipsch Palladiums and similar. On theese this compression is very evident.
But on more normal systems, let's say a B&W 600 series I do think you are quite correct.
But then again, you don't really dabble with "normal" systems do you..
-Tim
I am playing with double Alpha15s (4 in stereo) in 16" wide OB (various tops) and I can assure that symphony bass drum or jazz bass drum can be so frightning realistic that you will almost jump out of your seat when the tone is hit and played at normal live levels. It is like it is played directly beside where you sit.
I realize that Horn-loading also can give this kind of sensation.
This was also the reason for my question to Stig-Erik earlier.
/Erling
I realize that Horn-loading also can give this kind of sensation.
This was also the reason for my question to Stig-Erik earlier.
/Erling
Last edited:
I agree, though I don't see a contradiction between Erik's remark and the market addressed by overdubbed, heavily engineered recordings. Audio systems good enough to make compression, EQ, and all that fall apart are tiny fraction of overall playback compared to mp3 players and earbuds.
I am playing with double Alpha15s (4 in stereo) in 16" wide OB (various tops) and I can assure that symphony bass drum or jazz bass drum can be so frightning realistic that you will almost jump out of your seat when the tone is hit and played at normal live levels. It is like it is played directly beside where you sit.
I realize that Horn-loading also can give this kind of sensation.
This was also the reason for my question to Stig-Erik earlier.
/Erling
Interesting, do you have a pic of those 4 Alpha's OB?
I dont agree. Heavy mastering compression is easy to hear, but compression of individual instruments in the mix is far more difficult to detect. Compression is very widely used, even on so-called "audiophile" recordings, that makes them sound "fatter" and have more detail.Hi. Stig E. Im just chiming in
I'm a bit puzzled by this statement, because when i listen to this kind of artificial slam and punch though a transparent setup, it is quickly revealed as compression. In my oppinion it is only on low to midrange equipment that this method works.
For reference I'm talking about the Quad ESL's, Klipsch Palladiums and similar. On theese this compression is very evident.
But on more normal systems, let's say a B&W 600 series I do think you are quite correct.
But then again, you don't really dabble with "normal" systems do you..
-Tim
Drums are compressed dynamically on virtually ANY record you'll ever hear, even those who dont sound obviously compressed. Thats a fact.
Take a listen to the original (not the horrible *compressed* Japanse re-issues) Sheffield Lab Drum&Track record to hear an uncompressed drum track, and compare the average level of that with everything else. If the drums are louder than that, they must be compressed and/or peak limited.
An other example: The famous (?) Jazz at the Pawnshop record. Very heavy peak limiting and tape saturation, at least 12-15 dB compressed in peaks is my guess. Thats one of the reasons it sounds good!
Dynamic compression and peak limiting is even used on classical music.
Very interesting, and very similar to my own experience
I've heard a PA system (or maybe more than one) with very intense bass impacts. It seemed to be 'tuned' specially for kickdrum. (Those slams were very impressed at first, but also fatiguing shortly after.) I felf it's not 'slow' at all (to my ears & body), not like Michael's description above - "it takes time to build up" -- at least I could not detect the process of its 'building up'. They are so fast, " BANG ! " without any hint or sign, like an unexpected hit on the stomach right off the unseen corner.
I don't know if any compressor was used in that PA system. Those 'kicks' of the kickdrum just impressed me very much. However, like most 'boxed' speakers, it failed to impressed me on all other respects. The lines, pitches, plunks, and textures of the electric bass in the same band were all very awful. (It's very strange that the system delivered the 'kicks' of the kickdrum, but couldn't do the 'plunks' of bass right.... Don't know why.)
Of course I can not say the impressive kickdrum was correct, it's just a very strong presentation. (BTW, its decays were somewhat longer than I like.) Those initial "POPs" of the drum reminded me of the 'real thing' -- very high contrast of the burst and the silent prior to it. (It's funny that the real thing was indeed there, but the sound was picked-up, amplified and reproduced by loudspeakers)
I can not say that kind of high energy attacks are distortion or not. However it's very interesting to read reviews by almost everyone (who has built both boxed and OB speakers) stating that the dynamics of bass punches is somewhat weaker on OB while most well-built boxed ones sound more 'powerful' in this regard. I have the same feeling.
Please forgive my ignorance, but those 'impact', 'leading edge', 'attack'... etc. sort of things are the mid-high overtones, aren't they? And this character should be about how the sound 'start', not how they sustain or decay. And what would it look like if the 'LF' is overshot in a square wave? Most overshot square waves I've seen are coming with too high of initial rises, then oscillating for several cycles. That "too high of initial rise" should be HF, right? But why do these different type of bass sections in a low xover'ed 3way speakers make such a difference in the sense of "initial attack" of bass notes? My sense of hearing is playing trick on me?
Like most OB lovers, I love the rich details, tuneful sound, and clean decay in the bass of OB speakers I've built. However I also like those more jumpy, more dynamic, more 'attack' characters of the boxed speakers (especially horns). Or simply put, I'd like to have a bassdrum note with a combination of intense leading edge of a boxed speaker followed by the full, rich, and also delicate sustaining and decay portion of an OB. Be it incorrect or distorted, I'd still like to have it
I haven't heard any OB with 'intrinsic' high Q woofers, so I can't comment on those. Have played with drivers with Qts of 0.5, 0.4, and 0.3 on dipole, I found they all lack the initial attack of bass note (compared with boxed). EQ them flat (or even bass heavy) only helps in the RTA measurement with pink noise, not in music signal. (well, the EQ I was using is not phase linear... ).
In the last couple of days, I was thinking what's the difference between systems with:
1) intrinsic high Q woofer (say, Qts=1.0)
2) low Q woofer with phase linear EQ to render the FR equal to the above
3) low Q woofer with low damping amp to make a 'system Q' =1.0
I haven't figured them all out, yet.
Anyone?
The use of compression on individual instruments. Thinking about the techniques used.
Unfortunatly i dont have the Drum disc myself. Will see if i can borrow it.
-Tim
Its a good thing to have been working on a few recording projects, been in studios and watched what others do. If you do that you'll understand why records cant sound like "the real thing", and what you think sounds really dynamic in reality is quite the opposite.
I dont consider individual track or mastering compression a problem in it self - its just a tool that music producers use to make the music sound different or better. Its good when used properly. The problem today is that its used way too much, aka "the loudness war".
This is really the wrong forum for this topic though....
I dont consider individual track or mastering compression a problem in it self - its just a tool that music producers use to make the music sound different or better. Its good when used properly. The problem today is that its used way too much, aka "the loudness war".
This is really the wrong forum for this topic though....
Last edited: