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Thoughts on PRs vs. Vents
Over at Tech Talk there has been a lot of excitement over the new RS PR's. Rightfully so, though there is some sticker shock involved. It seems there is a shift taking place to PR's, however I have some thoughts, feels, whatever's about it all I would like to share an maybe discuss. Half is technical merit, half is what they actually sound like with music.
Yay! Drone cones! I use them, and if they were all that bad I would not have utilized one in my daughter's speakers I built her for Christmas. They are far easier to implement than vents, and there is no worry about noise, fitting it IN the cabinet and on and on. I do not find them to produce bass in any greater quantity or depth than a properly designed vented enclosure so in this instance they seem to be different means to the same end.
Where they begin to lose their wowie-zowie status with me is their awful transient response and are significantly more lossy than a vent. This is extremely visible in the group delay and roll-off which is far steeper than a vent. I believe this leads to a very distinct sonic signature that follows the old "slow" subwoofer analogies. It seems PRs can hit hard in their usable range (maybe because they operate in parallel with the drivers mechanically at their working frequencies?) However they sound bloated and instead of a "hit" often reproduce it as a "wumph".
In all DIY and commercial design alike using PRs, this quality is exhibited to one degree or another. On one extreme, the designed under-tunes the box looking for the extra 3 or 4hZ (Because 28 looks better than 32 on paper methinks) leading to a compressing but mono-tone drone up to at least an octave above the PR's active range, and on the other extreme it is like a subwoofer is in the room, set way too low causing the bass to fall like a rock well before expected save a little after boom down low.
In the middle, great executions of PRs that I have heard sound like a good speaker, with a properly tuned sub in the room...NOT a unified loudspeaker from top to bottom. Tidal came closest with their house-priced speakers, and one that was brought to DIY NY was just fine too.
Rubber meeting the road, there is no difference between vented and PRs when it comes to Pop, electronic, Rock, or just about any other heavily processed music. Yet throw on some folk, classical, jazz, or anything with natural instruments I find PRs to just muddy things up when listening most critically. Walking down an upright bass for example, or a well recorded, non close-mic'ed drum kit like those from the early jazz greats recordings. I do feel that the attributes I have found in PRs can be a good thing with certain kinds of music. Also, and maybe most importantly, they make a KILLER 5-min demo with the right material that will make small speakers sound less small, and big speakers compress a room with ease. A bit of a Pepsi challenge, though...no?
Vents suck too. The noise, the cabinet space, the mid-range leakage, gross non-linearity at high output. Eew. No wonder why the ease of a PR is desired. Well... They ARE a lot cheaper, no? There is far more flexibility to vents, however and things like group delay, tuning, slope shape, even excursion can be pretty meticulously controlled. The transient capability is on-par with any driver a vent is working with (air is pretty light) and the finest quality bass I have heard (aside from sealed) comes from vented alignments as executed by Vivid Loudspeakers, Early PSB (Stratus Gold i's in particular), and in the DIY world most memorable designs are vented. This comes in the from of listening at reasonable levels to music and not getting that speaker-to-sub transition feel, and a snap when required of the bass that is simply missed by PRs. Well executed vents can compress a room with just as much vigor, too.
So what does this roll up to for me? I'm cool with PRs. I will use em' again when required by the design without hesitation as I have several times in the past. I guess I think if real fidelity is the goal, a properly executed vent is the more desirable way to roll. This whole thing is one giant opinion-fest by me, assuming that things like group delay are indeed audible (there is evidence in both directions) presenting in the manner as described by the "slowness" of PRs and on and on. Neither are nearly as good as sealed but good luck finding a woofer anymore that has enough sensitivity and is optimized for sealed enclosures. Everything now is a "Works great for both!" flavor making them mediocre for both..Another rant for another time. However this may explain a lot of the recent PR love since they make more sense to a lot more drivers than a long vent that a designer is forced into with this "great for everything" drivers.
I don't want this to turn into some quote from experts stating group delay is inaudible, or our sensitivity down low negates effects, because I have read quite a few articles of this nature, and of the exact opposite leading me to believe that some people may simply be more sensitive than others. Not better or worse, just more sensitive.
Anyone notice quality differences between vents and PRs? Good/bad/indifferent?
TL;DR Drone cones and vents have distinct sonic differences (at least to me) and I do not understand why this is not considered more with the recent flare up of PR popularity.
Yay! Drone cones! I use them, and if they were all that bad I would not have utilized one in my daughter's speakers I built her for Christmas. They are far easier to implement than vents, and there is no worry about noise, fitting it IN the cabinet and on and on. I do not find them to produce bass in any greater quantity or depth than a properly designed vented enclosure so in this instance they seem to be different means to the same end.
Where they begin to lose their wowie-zowie status with me is their awful transient response and are significantly more lossy than a vent. This is extremely visible in the group delay and roll-off which is far steeper than a vent. I believe this leads to a very distinct sonic signature that follows the old "slow" subwoofer analogies. It seems PRs can hit hard in their usable range (maybe because they operate in parallel with the drivers mechanically at their working frequencies?) However they sound bloated and instead of a "hit" often reproduce it as a "wumph".
In all DIY and commercial design alike using PRs, this quality is exhibited to one degree or another. On one extreme, the designed under-tunes the box looking for the extra 3 or 4hZ (Because 28 looks better than 32 on paper methinks) leading to a compressing but mono-tone drone up to at least an octave above the PR's active range, and on the other extreme it is like a subwoofer is in the room, set way too low causing the bass to fall like a rock well before expected save a little after boom down low.
In the middle, great executions of PRs that I have heard sound like a good speaker, with a properly tuned sub in the room...NOT a unified loudspeaker from top to bottom. Tidal came closest with their house-priced speakers, and one that was brought to DIY NY was just fine too.
Rubber meeting the road, there is no difference between vented and PRs when it comes to Pop, electronic, Rock, or just about any other heavily processed music. Yet throw on some folk, classical, jazz, or anything with natural instruments I find PRs to just muddy things up when listening most critically. Walking down an upright bass for example, or a well recorded, non close-mic'ed drum kit like those from the early jazz greats recordings. I do feel that the attributes I have found in PRs can be a good thing with certain kinds of music. Also, and maybe most importantly, they make a KILLER 5-min demo with the right material that will make small speakers sound less small, and big speakers compress a room with ease. A bit of a Pepsi challenge, though...no?
Vents suck too. The noise, the cabinet space, the mid-range leakage, gross non-linearity at high output. Eew. No wonder why the ease of a PR is desired. Well... They ARE a lot cheaper, no? There is far more flexibility to vents, however and things like group delay, tuning, slope shape, even excursion can be pretty meticulously controlled. The transient capability is on-par with any driver a vent is working with (air is pretty light) and the finest quality bass I have heard (aside from sealed) comes from vented alignments as executed by Vivid Loudspeakers, Early PSB (Stratus Gold i's in particular), and in the DIY world most memorable designs are vented. This comes in the from of listening at reasonable levels to music and not getting that speaker-to-sub transition feel, and a snap when required of the bass that is simply missed by PRs. Well executed vents can compress a room with just as much vigor, too.
So what does this roll up to for me? I'm cool with PRs. I will use em' again when required by the design without hesitation as I have several times in the past. I guess I think if real fidelity is the goal, a properly executed vent is the more desirable way to roll. This whole thing is one giant opinion-fest by me, assuming that things like group delay are indeed audible (there is evidence in both directions) presenting in the manner as described by the "slowness" of PRs and on and on. Neither are nearly as good as sealed but good luck finding a woofer anymore that has enough sensitivity and is optimized for sealed enclosures. Everything now is a "Works great for both!" flavor making them mediocre for both..Another rant for another time. However this may explain a lot of the recent PR love since they make more sense to a lot more drivers than a long vent that a designer is forced into with this "great for everything" drivers.
I don't want this to turn into some quote from experts stating group delay is inaudible, or our sensitivity down low negates effects, because I have read quite a few articles of this nature, and of the exact opposite leading me to believe that some people may simply be more sensitive than others. Not better or worse, just more sensitive.
Anyone notice quality differences between vents and PRs? Good/bad/indifferent?
TL;DR Drone cones and vents have distinct sonic differences (at least to me) and I do not understand why this is not considered more with the recent flare up of PR popularity.
Comments
I didn't attempt to maximize low end F3. Instead, I used the PR to provide a very low tuning (17Hz) in a slightly undersized enclosure that offered a response closer to a sealed enclosure but with much better power handling and slightly lower extension. That type of alignment offers transient response closer to a sealed box and a better match to the room-gain curve.than the typical alignment meant to produce the lowest F3. Trying to do that with vents was simply out of the question as they would have had to be YUGE.
Done right, and for the right reasons, PRs can offer fantastic performance.