Do passive radiators have an impact in time domain accuracy and phase response between drivers? This would play a role in their use as a monitor such as the Yamaha NS10, for example. Though its sound was often characterised as unpleasant (one I chose to tolerate) the NS10 distinguished itself in time domain, relevant for parsing out certain relationships, between the bass and kick drum, for example. If PRs do impact time domain negatively, are there any design approaches to be utitlised as a workaround?
Related article on the NS10 and time domain, mostly a retrospective analysis as to why it became so favoured.
Related article on the NS10 and time domain, mostly a retrospective analysis as to why it became so favoured.
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Passive radiators functionally result in the same phase characteristics as a bass reflex alignment of the same tuning alignment.
They offer the advantage of doing that in a smaller box, as low tunings require vents that occupy far more space than a passive radiator.
To insure transient accuracy the phase response at the crossover must be aligned between a sub and the top cabinet.
That can be accomplished using a sealed, ported or passive radiator alignment.
I use a passive radiator sub with my near field monitors, with a foot switch to turn it off to hear how things sound without the lower octaves.
P.S. There are many near field monitors available now that have much smoother phase response without the terrible frequency response the NS10 has. I sold my NS 10s in 1992, have not missed them a bit in the last 22 years.
I wish I could hear as well now as back then, but that's another issue...
They offer the advantage of doing that in a smaller box, as low tunings require vents that occupy far more space than a passive radiator.
To insure transient accuracy the phase response at the crossover must be aligned between a sub and the top cabinet.
That can be accomplished using a sealed, ported or passive radiator alignment.
I use a passive radiator sub with my near field monitors, with a foot switch to turn it off to hear how things sound without the lower octaves.
P.S. There are many near field monitors available now that have much smoother phase response without the terrible frequency response the NS10 has. I sold my NS 10s in 1992, have not missed them a bit in the last 22 years.
I wish I could hear as well now as back then, but that's another issue...
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Thanks for the response – in this particular case, the application for the PR would be within a monitor cabinet itself, or any other speaker for that matter. A sub is not involved. I did not mean to imply use of a sub with passives mixed together with a set of NS10s. The question is basically whether the passive radiator impacts time domain accuracy, such as the case is in bass reflex designs over acoustic suspension. Btw, the above article on the success of the NS10 is fascinating if you're involved in studio work.
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Hi,
Simple answer is no, but yes if you added a PR to NS10's.
The NS10's are poor, and simply reflect a concensus that
they are similar to many other poor consumer speakers,
except being sealed they are not hideous bass boom boxes.
The time domain stuff is utter nonsense, in all respects.
rgds, sreten.
Simple answer is no, but yes if you added a PR to NS10's.
The NS10's are poor, and simply reflect a concensus that
they are similar to many other poor consumer speakers,
except being sealed they are not hideous bass boom boxes.
The time domain stuff is utter nonsense, in all respects.
rgds, sreten.
Correct me if i am wrong but Afaik you do add an extra "spring" to a ported design with a passive radiator. If a normal ported designs goes 24 dB / oct from -3dB down a passive radiator would go 30 dB down from -3dB = delay = slower for words lacking. The difference between normal port and passive radiator is steeper roll off down. ( don't know the exact terms, so shoot me)
Could be welcome in a 20 Hz -3dB sub, but not something you want in a 40 - 60hz -3dB speaker.
Could be welcome in a 20 Hz -3dB sub, but not something you want in a 40 - 60hz -3dB speaker.
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No intention of modding NS10s....the reference was mostly to do with the discussion of time domain in the above article, which highlights one of the reasons for their success. Yes, after years of listening to them, I'm very aware of their tonal characteristics. It's true that their almost universal presence in studios for three decades now can be attributed more to the need for a common measuring tool than their less than superlative sound, but the article presents the clearest case I've heard yet as to what else may be behind their acceptance. The author is mostly referencing Southampton University researcher Keith Holland's paper, which he links to.
Sreten, I would agree that the term 'time domain' has been used and abused in common audiophile speak/babble along with other sufficiently vague concepts such as timing (or is that the same?) but do you contend that its original meaning or method of measuring this, is really of no value?
weltersys, the foot switch approach sounds to be quite a useful one.
If anyone would care to discuss Keith Holland's paper and dispute his conclusions, perhaps we should. Open a new thread or keep it here?
Sreten, I would agree that the term 'time domain' has been used and abused in common audiophile speak/babble along with other sufficiently vague concepts such as timing (or is that the same?) but do you contend that its original meaning or method of measuring this, is really of no value?
weltersys, the foot switch approach sounds to be quite a useful one.
If anyone would care to discuss Keith Holland's paper and dispute his conclusions, perhaps we should. Open a new thread or keep it here?
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Around 8 years ago I realized my Tannoy PBM 6.5 (similar size to the NS10) which roll off below 48 Hz were not reproducing the LF of modern synth stuff.
I added a Mackie HRS120 sub, which happens to have a bypass switch jack.
The HRS120 extends response down to 16 Hz, as low as most of the better consumer subs. At the time, it went an octave lower than any of the "studio subs" I demoed, and had way more clean output and much more built in control features.
I use a momentary switch, so can step on it and hear what is kind of a typical home stereo cut off, when I take my foot off it reverts to an extended LF response.
Far easier than putting on headphones to check out the bottom octaves, and more representative of what anyone with wide band speakers would hear, phones just don't give the same feeling of weight as the same LF level through speakers.
The phase lag down at 16 Hz is of no concern to me, the wavelength is several times the dimension of my control room, so whether the phase was flat or lagging by a wavelength the net audible result is dominated by the room.
Upper transients define "attack and punch", it takes several wavelengths for our hearing to even define the pitch of VLF.
My home theater system (in the larger studio) uses a dual 12 sealed sub, in room is flat to the same LF as the passive radiator HRS120 sub.
I don't notice any LF difference between the two systems, playback translates well even though the LF designs are different.
Art
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Ethan Winer writes about the fallibility of our short term memory in accurately recalling sound, and it was with this in mind that that the momentary switch seemed to make a lot of sense. Winer gets at the idea that we're less capable of distinguishing differences when there's any significant lag of time between hearing version A and version B, so the 'fast-switching' approach sounds particularly useful.
On an intuitive level though, I would imagine a passive radiator could not be as fast to decelerate, if you will, as the main driver in a sealed enclosure. The PR is responding only to the actions initiated by the active driver, and therefore it seems there might be a degree of lag, theoretically, even if it's not particularly audible or perhaps difficult to measure, though the waterfall plots for time domain in the above piece would seem to show it is possible.
On an intuitive level though, I would imagine a passive radiator could not be as fast to decelerate, if you will, as the main driver in a sealed enclosure. The PR is responding only to the actions initiated by the active driver, and therefore it seems there might be a degree of lag, theoretically, even if it's not particularly audible or perhaps difficult to measure, though the waterfall plots for time domain in the above piece would seem to show it is possible.
The PR is damped by the cabinet air volume and it's suspension.
It may be measurably slower in returning to "0" than a driver, but by comparison to room ring at LF any overshoot is audibly small potatoes.
As far as phase response, the chart below shows the actual measured response of sealed Acoustic Research (pretty much the inventors of "acoustic suspension") woofer, a dual 12" bass reflex (Fb 36 Hz) and the passive radiator Mackie HRS120.
Attachments
Point regarding room ring at LF certainly taken – the room has a greater impact over many small system tweaks, though a true nearfield monitor setup in a room with sufficient damping may enable the slower return to "0" to be perceived.
Curious, what software are you using and would you give some additional interpretation as to what the graphs are revealing about phase and magnitude between the 3 speakers?
Curious, what software are you using and would you give some additional interpretation as to what the graphs are revealing about phase and magnitude between the 3 speakers?
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The software is Smaart v6.
Phase and magnitude response are always related, and real loudspeakers generally have more phase wrap the lower they go.
If the AR was equalized to have lower response, the LF phase would "flatten out" more like the Mackie HRS120, but would not have enough linear excursion to be usable down that low.
Post # 31 gives here gives some more insights:
http://www.diyaudio.com/forums/subwoofers/250159-technical-question-sealed-vs-ported-subs-4.html
Below are responses of the same cabinet, one with ports, and then sealed (IB, infinite baffle), it is easier to see the phase differences.
Certainly easier to see, than hear the phase difference ;^).
Phase and magnitude response are always related, and real loudspeakers generally have more phase wrap the lower they go.
If the AR was equalized to have lower response, the LF phase would "flatten out" more like the Mackie HRS120, but would not have enough linear excursion to be usable down that low.
Post # 31 gives here gives some more insights:
http://www.diyaudio.com/forums/subwoofers/250159-technical-question-sealed-vs-ported-subs-4.html
Below are responses of the same cabinet, one with ports, and then sealed (IB, infinite baffle), it is easier to see the phase differences.
Certainly easier to see, than hear the phase difference ;^).
Attachments
Hi lucadelcarlo,
Your OP piqued my interest, so I did some sim's in LEAP and processing in Fitershop with results shown attached.
The two attached PDF's show the magnitude response and step response of three systems, Sealed, Vented and Drone. The responses were made using LEAP's Quick Design using the same driver for each system. A Butterworth response was selected for each of them.
Hope they are of interest.
Regards
Peter
Your OP piqued my interest, so I did some sim's in LEAP and processing in Fitershop with results shown attached.
The two attached PDF's show the magnitude response and step response of three systems, Sealed, Vented and Drone. The responses were made using LEAP's Quick Design using the same driver for each system. A Butterworth response was selected for each of them.
Hope they are of interest.
Regards
Peter
Hi lucadelcarlo,
I didn’t post the group delay responses as described by Filtershop yesterday, because quite frankly, I was concerned that the Drones response in particular did not appear correct, but after checking the GD results give by Praxis, it appear that the Filtershop responses were indeed correct. So here are the GD results together with the Phase responses of the Drone, Vented and Sealed systems.
As you can see, the Drone systems GD looks alarming, but how this is perceived in the presence of room reflections and modes, I don’t know. Hopefully someone much more knowledgeable than I can chip in here and put it all in perspective.
Regards
Peter
I didn’t post the group delay responses as described by Filtershop yesterday, because quite frankly, I was concerned that the Drones response in particular did not appear correct, but after checking the GD results give by Praxis, it appear that the Filtershop responses were indeed correct. So here are the GD results together with the Phase responses of the Drone, Vented and Sealed systems.
As you can see, the Drone systems GD looks alarming, but how this is perceived in the presence of room reflections and modes, I don’t know. Hopefully someone much more knowledgeable than I can chip in here and put it all in perspective.
Regards
Peter
From Tolvan
"Passive radiator
The vent can also be realised as a passive radiator. In this case, no tube resonances will appear. An extra compliance CASP is added, originating from the suspension of the cone. Just as for the lumped model the flow into the inside the radiator is the same as the flow out of the outside. Contrary to the lumped model of a tube, this model is accurate also for higher frequencies, as there are no tube resonances.
The passive radiator model of the vent and the equivalent circuit diagram of its acoustic properties."
"Passive radiator
The vent can also be realised as a passive radiator. In this case, no tube resonances will appear. An extra compliance CASP is added, originating from the suspension of the cone. Just as for the lumped model the flow into the inside the radiator is the same as the flow out of the outside. Contrary to the lumped model of a tube, this model is accurate also for higher frequencies, as there are no tube resonances.
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