The missing Link - GD EQ
In a life long search for accurate and low bass.... I have only found one thing to make a truely full-filling sound down there...... just large size drivers....[all else being equal]. 2-way speakers dont move me in the bass. Three ways work best but still.... if they dont move volumes of air easily and readily... it just doesnt seem to satisfy. 6.5 or 8 and 10 inchers dont get it done.
Now I have 4 - high effec 15 inch bass drivers and two 18 inch subs. Easy, effortless, deep, clean and accurate without strain or increasing distortion. With driver area comparable to a kick-drum, kick drums can actually sound like an undamped kick drum. kettle drum? No problem. The hard part is with the cross-overs and that GD. GD may be the last boogy-man that really can substantially improve a system..... it isnt BW or THD or S/N that needs more attention... it is Group-Delay and its EQ.
We need some one here to design us a GD equalizer for <500Hz. Or modify an existing DSP based product to do it?
THx-RNMarsh
In a life long search for accurate and low bass.... I have only found one thing to make a truely full-filling sound down there...... just large size drivers....[all else being equal]. 2-way speakers dont move me in the bass. Three ways work best but still.... if they dont move volumes of air easily and readily... it just doesnt seem to satisfy. 6.5 or 8 and 10 inchers dont get it done.
Now I have 4 - high effec 15 inch bass drivers and two 18 inch subs. Easy, effortless, deep, clean and accurate without strain or increasing distortion. With driver area comparable to a kick-drum, kick drums can actually sound like an undamped kick drum. kettle drum? No problem. The hard part is with the cross-overs and that GD. GD may be the last boogy-man that really can substantially improve a system..... it isnt BW or THD or S/N that needs more attention... it is Group-Delay and its EQ.
We need some one here to design us a GD equalizer for <500Hz. Or modify an existing DSP based product to do it?
THx-RNMarsh
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And it is not just the music per se, but the whole environmental experience which benefits from a deep bottom. We are used to heavy doses of 1/f ambient noise in live venues. To reproduce those at home makes everything more real.
The literature keeps making the point that in production there are many ways to mess up GD at LF. How do you propose to know if a recording engineer used a 5Hz low pass at the input or a 5 pole 10Hz Butterworth or nothing? The low cutoff on a mike is min-phase each one different.
Dan, that's the piece. but ufortunately, it doesn't really compare with the LP version, even in case of my modest setup. It took my Luxman C-03 preano, with a very elaborate phono RIAAstage to get it into its actual recorded glory from the CD. I'll try to do better in July, when I finally unwrap and set up my entire system, memory sticks are dirt cheap nowdays, and I'll thro in some extras you won't find anywhere as a free bonus. That's a promise. Zero compression, straight 16 bits.
And who care ? The artist, the producer and the sound engineer had agree the bass or the kick drum sounded better this way ;-)
They Lyra has a compliance of 20 at 100Hz. I think Ortofon spec their compliance at a more realistic 10Hz. The Lyra would probably be on the order of 15-18 at 10Hz, so the difference would be less dramatic than it would seem at first blush. (Somebody probably already said this, I'm a couple of days behind.)
Edit: The Ortofon is also lighter at 7.2g, which in the same arm would give it a slightly higher resonant frequency.
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you have to start somewhere. I can EQ for flat GD in my playback system(s). From my source output to speaker output.
As for the recording side..... what ever the producer heard and wanted - and musicians.... I want to hear it the same as they intended me to hear it.... complete with the perceived good-bad-and the ugly in it.
But, I suspect that if there were products being used to EQ the GD on playback... it wouldnt be long before same was being done to record side...... maybe not in the creation of the musics 'sound' (exception HD or Hi Rez may have it done straight) But nothing added during play back. I would not want added GD any more than I would want added noise or distortion.
Got a variable EQ circuit for GD? Commercial or DIY design/build?
THx-RNMarsh
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Richard,
Just from the little that I have picked up about you speaker system I can assume that the system is far from a time aligned system and no manner of manipulation of a distributed set of speakers as you have can ever be truly time aligned. That being the case what are you doing about such simple things as the phase alignment of all these different devices that makes you so concerned about the group delay that you also have in each single device? It seems like anything less than a dsp solution, if there is truly one that can do all you are attempting to do, is the only way to look at this. Otherwise it seems like you would just be chasing your tail as they say, one correction messing with another trying to integrate all of this into a system.
ps. Have you been following the Rephase thread where I think many of your questions may be answered?
Just from the little that I have picked up about you speaker system I can assume that the system is far from a time aligned system and no manner of manipulation of a distributed set of speakers as you have can ever be truly time aligned. That being the case what are you doing about such simple things as the phase alignment of all these different devices that makes you so concerned about the group delay that you also have in each single device? It seems like anything less than a dsp solution, if there is truly one that can do all you are attempting to do, is the only way to look at this. Otherwise it seems like you would just be chasing your tail as they say, one correction messing with another trying to integrate all of this into a system.
ps. Have you been following the Rephase thread where I think many of your questions may be answered?
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Steven, if you use some kind of digital active filter, like the Behringer DCX2496, you can set delays to all the ways in order to align them on a temporal point of view, even if the speakers coils are not vertically aligned.
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Esperado,
Yes that us true but only for a single point in space. There is no real way to align a system like that for more than that single point, it is not possible with the different axis that the multiple device are on. So phase alignment follows this same premise, it only works if you have your head in a vice, move a foot this way or that and everything is off again.
Yes that us true but only for a single point in space. There is no real way to align a system like that for more than that single point, it is not possible with the different axis that the multiple device are on. So phase alignment follows this same premise, it only works if you have your head in a vice, move a foot this way or that and everything is off again.
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Did you mean the speakers that Richard use are not situated in a unique vertical plan in each enclosure ?
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No, I am making the simple statement that the only way to have true time alignment is with either a full range speaker or a coaxial speaker, nothing else can ever be truly time aligned in more than a single point in space. I can get out my AES journal and site the relevant articles showing this is not possible. This misnomer of time alignment is just that, not real.
- I know no full range speaker with a flat Group delay.
- In a coaxial speaker the two ways are (most of the time) distant in depth in its axis while they will be aligned at 90°. Not good neither.
If you align physically the virtual source of the speakers in a multiway enclosure, you will keep the phases in an horizontal plan, don't you think ?
They are one and the same thing...........analog EQ affects group delay in a defined way, know one know the other. Check it out. Flat playback EQ has zero group delay. I think there is much misunderstanding about what group delay means, and how it arises, on this thread. There's a set relationship between EQ, phase and group delay which is fixed in nature, well for natural filters anyway, be they electronic or mechanical in origin.
The KEF driver is a true coaxial with proper alignment. See Stereophile's tests of their LS-50 and Blade.
I think he means GD alone not amplitude so has to be DSP or these days an off the shelf PC will do.
Dick, this might be on the right track MAYBE you can construct an FIR allpass with adjustable group delay.
Gardner, W. G. (1994). Efficient convolution without input-output delay. Presented at the 97th convention of the Audio Engineering Society, San Francisco. Preprint 3897
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