Power Meter Brands

Leroy42

godtabh wrote: »

Personally at my level the l.r balance isnt an issue. Consistency is key ie temp changes arent going to affect readings.

Thats were you are wrong. You are only at this level as you don't have all the data in order to correct some of the issues.

If only yu had access to L/R split, pedal efficency, rotational power distribution and the like. If you had that there is no limit to your potential.

All that is holding you back is this. What price on immortality, to be considered the bestest ever? Surely the price of a SRM is worth it:P

doozerie

My own perspective on choice of power meter is obviously biased by my experiences to date but it amounts to my remaining interested in the Brim Brother’s product despite it coming in at a higher price than I’d hoped.

I’ll skip past the pointless attempts to justify a power meter for someone at my level, I already have one so I’ve overcome that particular mental hurdle already. I bought a Powertap when it was on sale at a price, about 600euro, that I considered pretty reasonable and the value I place in it is based on that price (i.e. if I were buying one for the typical/full retail cost it would have to offer me more to justify its purchase). By the time I bought a rim and spokes for it the completed wheel came in at around 700euro. I ride Campag, my wife rides Shimano, so buying a Shimano freehub added another 100euro to that.

So I have a power meter which is usable by either my wife or myself. But I run it with 25mm tyres, my wife generally uses 23mm tyres, so swapping between bikes is inconvenient not just from the point of view of swapping the freehub. What’s more, it is a 36-hole hub and with me choosing robust spokes over light spokes for the build, the overall weight of the wheel is significant compared to the lighter wheels I favour for racing (despite my choosing a light rim for it). So to date I’ve used the wheel for only one race, despite my having a strong desire to be able to review my power output after a race. It’s also a shallow section rim, etc., so the usual headache applies that paring this wheel with a similar front one when moving between different scenarios is limiting.

So for 800euro, I have a power meter that:
* I mostly don’t use for racing despite wanting to.
* we rarely swap onto my wife’s bike despite wanting to.
* I don’t use on my turbo trainer because I already have a dedicated turbo trainer wheel that has a very close ratio cassette which suits that purpose perfectly.
* has moving parts, the bearings, which I haven’t been impressed by and which I believe will continue to need replacing more regularly than I’d like, with the risk of expensive damage to the hub each time (I replace the bearings myself).

I may rebuild the wheel with lighter spokes at some point, which will increase the overall cost to closer to 900euro, and will (partly) address only the weight issue, all of the other “issues” will remain.

None of these issues are significant enough to make me want to get rid of my Powertap. I like it when I use it, it just doesn’t get used as much as it could. If I were buying another power meter right now though then the Brim Brothers product would look like very good value by comparison - for about the same cost (900euro -ish), with the Zone I’d have a power meter which I could transfer between all of my bikes without thought, and for any scenario (training, racing, turbo), one which has no moving parts to worry about, and one which give me even more data (left and right) to melt my head with.

The Zone certainly would not solve all of the relatively minor issues I currently face, such as being easily transferable to my wife’s bike (she uses Speedplay too, and our feet are almost, but not quite, the same size, so funnily enough it’s actually very close to transferable in our case but just falls slightly short), or dealing with the fact that I use different shoes for racing versus training, but given a choice between a Zone and a Powertap I’d be swayed by the Zone assuming that the first version released proves to be reliable and consistent. I’ve not used a crank-based power meter, but some of the same issues/limitations would arise with those as I currently encounter with my Powertap, so again the Zone would be a strong contender against those too, for me.

Having said all of that, I don’t actually plan to buy a new power meter any time soon. I do plan to watch how the market changes over the next few months though. The Zone is appealing on paper today but by tomorrow there may well be some other new power meter that fits even better with what I want. It’s great that there is such innovation in the power meter market at the moment, but with the range of new products hitting the shelves it’ll take a while yet before some of the more subtle pros and cons of each become obvious.

mossym

doozerie wrote: »

I’ve not used a crank-based power meter, but some of the same issues/limitations would arise with those as I currently encounter with my Powertap, so again the Zone would be a strong contender against those too, for me.

.

i was looking at powertaps initially, and the same issue as you brought up put me off. i use one set of wheels on the turbo, i use a set of wheels for normal riding outside, including training. and i have a set of race wheels(Deep rim carbons). the normal outside wheels are kysriums which are shared between my road bike and the tri bike. i then need power across all 3 sets of wheels. no good with a powertap.


swapping a crank based system over though is pretty straight forward, and can be done in very little time. Maybe not as much time as a straight shoe swap, but quick enough to be feasible before every ride if needed, which usually isn;t the case.

my main use for the PM is for tri's, so the shoe based system is out immediately, not going to work when you've got to get shoes on quickly, while already pedalling on the bike. besides that, i'm not sure i like the idea of it. my cleats get pretty beat up, what's lifetime like on these? how are they going to work with thick waterproof covers all winter? MY HRM gets thrown off by a thin layer of material near it, are these going to suffer the same issue?

time will tell i guess. but weren't BB originally heralding their PM as relatively cheap? it's far from that now. it's up at the premium end of pricing. and i don;t see it competing with the likes of SRM and other crank based systems. i think it will struggle

doozerie

@mossym, I assumed that cleat-based power meters would be fine for triathlon given that people typically leave their shoes attached to the pedals, but I may be oversimplifying the requirements entirely, I guess.

Re cleats, my Speedplay cleats last quite a while, I haven’t kept track of the mileage but I’m pretty sure I get over 15,000km out of one set of cleats and it may even be more than that. I think the rate of wear varies from person to person though. Last time I replaced a set of Speedplay cleats I think most of the wear was in the black plastic adaptor that sits between the cleat proper (the yellow plastic inner layer plus the metal outer layer) and the shoe. The pedal contacts this adaptor and wears it down over time between clipping in and out and presumably from direct downward pressure too - my downward pressure would be modest compared to many people and I also don’t clip in and out much during a ride.

That outer metal layer of the cleat provides substantial protection to the inner layers of the cleat too, so I would expect that the Zone electronics would be mostly safe from the wear and tear that the cleat itself undergoes, as they are (I think) buried away between the cleat and the shoe. I do vaguely recall seeing photos of early versions of the Zone though where there was a wire running up from the cleat to the pod on the top of each shoe so unless they’ve changed that aspect of the design (which I expect they have) there would presumably be some risk of damage to that during normal use.

As for crank-based power meters, because I ride Campag this rules me out of some of the options there. Last time I checked, Stages doesn’t have an offering for carbon cranks, for example. Mind you, if the brief reference in the review of the 4iii linked to above is to be believed then it looks like that’s one crank-based option that will probably work with Campag’s carbon cranks.

Another potential headache with crank-based power is whether the meter needs recalibration if you swap chainrings. From memory I think that Power2Max doesn’t need recalibration but on the other hand would it also allow you to swap easily between standard and compact chainrings? I have to admit I’ve never felt the need to change my standard chainrings for compact ones, but my ageing knees are suddenly keen for me to take an interest in Campag’s 2015 groupsets, some of which allow you to swap from standard to compact on the same spider. I’d never have stopped to ask whether a crank-based power meter would allow me to do that, in the past, and now I find myself adding it to the list of requirements for an “ideal” power meter. It’s another subtle piece of functionality that might appeal only to a limited audience, but it might push that audience strongly in the direction of pedal-based or cleat-based power meters perhaps.

mossym

@doozerie some tri guys use elastic bands to hold their shoes in the normal position so it's easier to get going when you get on the bike. it's never worked for me. i leave my shoes in the pedals, but they are free to rotate, and often take the odd whack off the ground. notthe best for sensitive transmitters. at the dismount line, everyone is the same. A lot of tris have people assigned to pick up the shoes that get knoecked off from people dismounting. again, i'm not sure BB will have designed their shoes for that.

this is the cycling forum though, so that's not going to be a concern for most, and i ackowledge that

re the p2m, i have one. you can swap chain rings no problem, without calibration(not all crank based systems are like that though). However, when ordering the p2m, you have to choose a 130 or 110bcd, which limits what rings you can fit later. i've a 130, which has me on a standard. raced half ironman in kenmare 2 weeks ago, up healy and caha pass and wasn;t stuck for gears, even with a bottom gear of 25 on the back. Going for a 110 would have allowed the choice of a compact or semi compact. so you are limited in what you can do based on the choice you make when buying.

if the campag allows the same spider though, that must all be the same bcd so, right? In that case something like the campag p2m would allow you both.

in other news, i see dcrainmaker has posted his first look at the brooks brothers. Power readings all over the place. again a rogue occurence.yeah right. more offputting though...the battery life is 12 hours. 12 hours. barely enough to get you over a good weekend of cycling. my p2m gets 100 hours i think. you'd be charging almost weekly. the di2 on my road bike gets charged less often by a number of factors

BenEadir

This is interesting ref Brim Bros PM http://www.dcrainmaker.com/2014/09/brothers-announces-production.html

godtabh

mossym wrote: »

raced half ironman in kenmare 2 weeks ago, up healy and caha pass a

Impressive as part of an Ironman Triathlon(but has to be discounted as its a Triathlon)

Inquitus

mossym wrote: »

...the battery life is 12 hours. 12 hours. barely enough to get you over a good weekend of cycling. my p2m gets 100 hours i think. you'd be charging almost weekly. the di2 on my road bike gets charged less often by a number of factors

My Stages still hasn't missed a beat just got the low battery warning after @150+ hours, you really don't need to be faffing having to remember to charge your PM imo. Disappointed with the Brim review, reading as you say all over the place, the 4iiii went much better.

mossym

Inquitus wrote: »

My Stages still hasn't missed a beat just got the low battery warning after @150+ hours, you really don't need to be faffing having to remember to charge your PM imo. Disappointed with the Brim review, reading as you say all over the place, the 4iiii went much better.

i had a look again, it's 15 hours, not 12, but yeah, you're right. my p2m gets 100 hours, and can throw a spare battery on whenever i want.

reading the initial impressions, if you were basing it on those you;d go with the 4iii alright

tunney

mossym wrote: »

i was looking at powertaps initially, and the same issue as you brought up put me off. i use one set of wheels on the turbo, i use a set of wheels for normal riding outside, including training. and i have a set of race wheels(Deep rim carbons). the normal outside wheels are kysriums which are shared between my road bike and the tri bike. i then need power across all 3 sets of wheels. no good with a powertap.


swapping a crank based system over though is pretty straight forward, and can be done in very little time. Maybe not as much time as a straight shoe swap, but quick enough to be feasible before every ride if needed, which usually isn;t the case.

my main use for the PM is for tri's, so the shoe based system is out immediately, not going to work when you've got to get shoes on quickly, while already pedalling on the bike. besides that, i'm not sure i like the idea of it. my cleats get pretty beat up, what's lifetime like on these? how are they going to work with thick waterproof covers all winter? MY HRM gets thrown off by a thin layer of material near it, are these going to suffer the same issue?

time will tell i guess. but weren't BB originally heralding their PM as relatively cheap? it's far from that now. it's up at the premium end of pricing. and i don;t see it competing with the likes of SRM and other crank based systems. i think it will struggle

I ride my road bike at the weekends in Spesh S-Worx shoes. I race tris in Spesh Transitions........

tunney

doozerie wrote: »

@mossym, I assumed that cleat-based power meters would be fine for triathlon given that people typically leave their shoes attached to the pedals, but I may be oversimplifying the requirements entirely, I guess.

Train in road shoes, race in tri ones......

doozerie wrote: »

As for crank-based power meters, because I ride Campag this rules me out of some of the options there. Last time I checked, Stages doesn’t have an offering for carbon cranks, for example. Mind you, if the brief reference in the review of the 4iii linked to above is to be believed then it looks like that’s one crank-based option that will probably work with Campag’s carbon cranks.

4iii dodged that question.

doozerie wrote: »

Another potential headache with crank-based power is whether the meter needs recalibration if you swap chainrings. From memory I think that Power2Max doesn’t need recalibration but on the other hand would it also allow you to swap easily between standard and compact chainrings?

No would be the answer here. SRMs for sure don't need recalibration.
Also calibration is not a bad thing. If you cannot calibrate you cannot verify.

doozerie wrote: »

I have to admit I’ve never felt the need to change my standard chainrings for compact ones, but my ageing knees are suddenly keen for me to take an interest in Campag’s 2015 groupsets, some of which allow you to swap from standard to compact on the same spider. I’d never have stopped to ask whether a crank-based power meter would allow me to do that, in the past, and now I find myself adding it to the list of requirements for an “ideal” power meter. It’s another subtle piece of functionality that might appeal only to a limited audience, but it might push that audience strongly in the direction of pedal-based or cleat-based power meters perhaps.

This Zones will go the way of the Ergo.

Inquitus

doozerie wrote: »

Last time I checked, Stages doesn’t have an offering for carbon cranks, for example. Mind you, if the brief reference in the review of the 4iii linked to above is to be believed then it looks like that’s one crank-based option that will probably work with Campag’s carbon cranks.

Stages don't do Carbon cranks as the deflection of Carbon is not uniform, making it impossible to accurately calculate power. I don't see how 4iiii can get round this basic issue.

From Stages:

Carbon composites don’t offer reliable power measurement because there’s no consistent deflection curve to measure, the company says.

mossym

tunney wrote: »

I ride my road bike at the weekends in Spesh S-Worx shoes. I race tris in Spesh Transitions........

i hadn't thought this would be an issue for the brooks pm until i saw the install notes. glue, stickers? not only for triathletes, but i know a few guys who put away their expensive shoes during the winter and wear shoes they don't mind getting wet and muddy/beat up. i think they missed the boat here as well

godtabh

mossym wrote: »

i hadn't thought this would be an issue for the brooks pm until i saw the install notes. glue, stickers? not only for triathletes, but i know a few guys who put away their expensive shoes during the winter and wear shoes they don't mind getting wet and muddy/beat up. i think they missed the boat here as well

I do that.

tunney

From Barry at Brim on DCRainmaker

"We state that it requires a strap, to fix the pod to, but it is possible that you might be able to fix the pod to BOA or other lacing systems. We don't recommend that or support it. "

I use Boa on all my shoes, would not dream of straps now, BOA so much more comfortable

doozerie

mossym wrote: »

if the campag allows the same spider though, that must all be the same bcd so, right? In that case something like the campag p2m would allow you both.

I had myself convinced that I'd read somewhere that Campag uses 110 BCD for (some of) their 2015 groupsets, but searching just now I couldn't find any such statement, just a generic and potentially misleading "standard single BCD pattern" reference. It actually looks like they use one BCD for the inner chainring and another for the outer chainring (as per this video) but I couldn't find it stated definitively anywhere what either BCD actually is. So I wonder whether the new spider will take proprietary Campag chainrings only, in which case the P2M might not support them. I guess that'll become clearer soon enough once the new groupsets appear in the shops.

Fundamentally though, I'd have reservations about any power meter that restricted me in some way or other. Unfortunately that applies to most of the ones on the market at the moment that I am aware of - hub-based ties you to the rim and spokes it is built with, crank-based ties you to the gearing ratios of their supported chainrings, etc. The Zone obviously restricts you to a specific pedal too, it just happens to be a pedal that I already use so that restriction is not currently an issue for me. Ideally I'd like no restriction at all though, which is probably a bit pie in the sky as yet unless I'm willing to seriously consider the iBike Newton Plus (which I find interesting, promising even, but I can't quite overcome my doubts about its reliability, maybe too many years of dealing with software and its inevitable bugs has left me overly cynical - I guess the joy of just being a window shopper means I can be as fussy as I like though ).

godtabh

i considered the netwon (and did a lot of research on it) but when I read that it doesnt work in rain it wasnt for me!

Inquitus

doozerie wrote: »

crank-based ties you to the gearing ratios of their supported chainrings, etc.

Shimano Ultegra 6800 only has one BCD for all Chainrings which is a step in the right direction.

Inquitus

godtabh wrote: »

i considered the netwon (and did a lot of research on it) but when I read that it doesnt work in rain it wasnt for me!

I read up a lot on it as well and concluded it wasn't at the races compared to the real power measurement options.

godtabh

Inquitus wrote: »

I read up a lot on it as well and concluded it wasn't at the races compared to the real power measurement options.

The principle in which it is based on is sound (opposite forces hence the name) but the measurement of this forces accurately is the issue.

If I remember correctly the wind sensor is affected by rain drops and you can get a funnel to eliminate this.

doozerie

Inquitus wrote: »

Shimano Ultegra 6800 only has one BCD for all Chainrings which is a step in the right direction.

I agree, and when I read that Campag were going the same route for some of their 2015 groupsets I optimistically assumed that this represented a shift to a common standard across manufacturers but I'm now not sure whether it really does. If Campag and Shimano continue to differ in BCD between their cranksets, even if they each use a common BCD across all of their own chainrings, then that'll continue to create headaches on the crank-based power meter front too, unfortunately. As ever, the word "standard" means a different thing in the cycling world than it does in some other areas

Sarz91

godtabh wrote: »

The principle in which it is based on is sound (opposite forces hence the name) but the measurement of this forces accurately is the issue.

If I remember correctly the wind sensor is affected by rain drops and you can get a funnel to eliminate this.

The fact that you've to re calibrate every time yours or the bikes coefficient of drag changes is a pretty big negative for me.

You calibrate it before you go out for a training spin with normal wheels, a loose rain jacket and you ride pretty upright for 90% of the ride. Your coefficient of drag might read .9. Go out again with aero wheels, no flappy jacket and you spend 90% of the time on the drops and your coefficient of drag might be as low as .5 but the newton still has a coefficient of drag of .9 as you never calibrated again.

I'd rather a power meter be precise and wrong than have a power meter that is 95% accurate some of the time but not at all precise.

SwiftJustice

harringtonp wrote: »

Speed read DC's report and the watt values are much lower for it and we're not talking 1-2%. It is early but I'd be wanting to see readings for it that are consistent with other units.

It dosnt have to be consistent with any other unit, it just has to be consistent with itself. The powermeter output could be in a scale of oranges and still provides the same information to the user....

"I know I can hold 15oranges for 10 min before I blow up"...

harringtonp

SwiftJustice wrote: »

It dosnt have to be consistent with any other unit, it just has to be consistent with itself. The powermeter output could be in a scale of oranges and still provides the same information to the user....

"I know I can hold 15oranges for 10 min before I blow up"...

Appreciate that but I put in a winter training on a gym bike with power before buying power2max and found that the gym bike figures were way higher than the PM. So looking forward and down the line I'd line to thinking that if I ever replaced the P2M with something else that the figures remain within 2-6W.

It is nice to be able to track progress accurately over a long period of time.

mossym

SwiftJustice wrote: »

It dosnt have to be consistent with any other unit, it just has to be consistent with itself. The powermeter output could be in a scale of oranges and still provides the same information to the user....

"I know I can hold 15oranges for 10 min before I blow up"...

100% right. if you make the asumption that the change is linear as power increases.

what if your balance changes as your power goes up? Now you do an ftp test, your balance is 40-60 L/R.you get 2* the 40% reading. then you say okay i'm doing a race, i want to hit 70% ftp for that race.but at 70% your balance is 44-56. now all of a sudden you're off what you should be doing.

and this is still the stages being consistent. it can do this every time. just means it will be wrong every time. (it's early, still ahving first coffee,but without doing the maths you;d be riding easier than you could be).

what proof is there it changes? have seen it reported several times, plus here is test data from a user
http://forum.slowtwitch.com/cgi-bin/gforum.cgi?post=5245664#5245664

worryingly, the reading is the same at low power, then changes dramatically as power goes up. That means it's not consistent with itself, it's not a linear change.

so, how come sky use it? enough testing to have enough data to work around this. indidivually tweaked units, i don't know. where i work we can drive our products to limits customers never could jsut becuase we have characterised them to such a level. customers could do it too, but it would take a long time. likewise, you could get around this by measuring your l/r balance at every power level, and using that to correct the error(even every 10w would likely be enough to remove most of the error).

If you just want it to see if you got stronger, it probably works. if you want it to push performance as close to the edge as possible(racing), initially i thought they would be fine, but i'm doubting that now.

Leroy42

^^but that assumes that you use the PM as your determining factor while racing, rather than a useful tool to gather information after the event and to probide on the bike info during the race. But if someone else if gong faster then you either choose to go with them or not, the PM will only form part of that.

You need to listen to your body, how are you are feeling, what stage the race is, how many others are around, what you need out of the race.

And again, even if the left right split isn't linear does it matter. The actual PM reading is actually fairly useless. I am lighter than some others, so in many cases my PM readings are less than theirs but we climb exactly the same. So the actual Watts number is applicable to me only. YEs it is nice to be able to see against others, but you also need their weight to give a proper comparison, and the time of the power.

It is only by using the PM on a consistent basis, analysising the information and comparing it against HR and PE that a full picture as to the numbers will be obtained. Whether those numbers represent the real number is kinda irrelevant. If I know, from my training, that I can hold 200W for 5 minutes, but if I go to 250w I can only hold that for 1 minute, then that is the key information. How the 250W was calculated is irrelevant, once it is calculated consistently.

I agree that having the porper split is better, but there is a price to be paid for that.

Juan More Time

I can't envisage buying a power meter at the moment, but when funds allow will get a stages.
They seem to be coming down in price significantly over the last couple of months, as the cheapest dura ace 9000 stages has now been reduced to €764 from powermeter24 in Germany. On the face of it it still seems a lot for just a left hand crank arm with some added electronic gubbins, but it still blows other power meter designs out of the water for both price and convenience.

The powertap is supposedly a good unit, but you are then tied to using the same wheelset, while the new pioneer unit is still in the region of €1400. While SRM is have an excellent product that has served many sponsored teams well in the past. I guess it's only a matter of time before SRM the will be out of business if they don't move with the times and sell more affordable products.

mossym

Leroy42 wrote: »

^^but that assumes that you use the PM as your determining factor while racing, rather than a useful tool to gather information after the event and to probide on the bike info during the race. But if someone else if gong faster then you either choose to go with them or not, the PM will only form part of that.

You need to listen to your body, how are you are feeling, what stage the race is, how many others are around, what you need out of the race.

And again, even if the left right split isn't linear does it matter. The actual PM reading is actually fairly useless. I am lighter than some others, so in many cases my PM readings are less than theirs but we climb exactly the same. So the actual Watts number is applicable to me only. YEs it is nice to be able to see against others, but you also need their weight to give a proper comparison, and the time of the power.

It is only by using the PM on a consistent basis, analysising the information and comparing it against HR and PE that a full picture as to the numbers will be obtained. Whether those numbers represent the real number is kinda irrelevant. If I know, from my training, that I can hold 200W for 5 minutes, but if I go to 250w I can only hold that for 1 minute, then that is the key information. How the 250W was calculated is irrelevant, once it is calculated consistently.

I agree that having the porper split is better, but there is a price to be paid for that.

an honest question. is that an argument about the stages left only reading, or aginst having a pm at all?

your view of racing is very focused on one type. what about time trials? training for the races you're talking about? these are where the pm is invaluable.
these are where the errors i described rear their head.


if you're going to ignore the pm in favour of how you feel when you see the other guy go, then why bother having one at all? just go by feel. if you have one, it's becuase you value the input. in that case, say you get in a break. you;re putting out 350w. you know that's 10 minutes max for you, but you're 20 mins from the finish at current pace. now what? at least if the numbers are accurate you can use the info. if the numbers are off like i said, then what good are they?

i agree completely about using it regularily, because it lets you build up the profile of how it works. that's my exact point, if the stages isn't linear, then you can't predict anything. you say as long as it calculated consistently, mylast post was allabout the fact that it isn't calculated consistenty. it only works if your l/r balance is the same at all power levels, which testing is showing is not the case.

as for the different weights going up the hill,that's why w/kg is a much more realistic meaurement. i knowa guy who i reckon to be strong on the bike. was well impressed when i got my PM that my ftp was near his. then i remembered he's 10kg lighter and 4 inches smaller then me. so in other words he'd kick my ass.

mossym

Juan More Time wrote: »

I can't envisage buying a power meter at the moment, but when funds allow will get a stages.
They seem to be coming down in price significantly over the last couple of months, as the cheapest dura ace 9000 stages has now been reduced to €764 from powermeter24 in Germany. On the face of it it still seems a lot for just a left hand crank arm with some added electronic gubbins, but it still blows other power meter designs out of the water for both price and convenience.

The powertap is supposedly a good unit, but you are then tied to using the same wheelset, while the new pioneer unit is still in the region of €1400. While SRM is have an excellent product that has served many sponsored teams well in the past. I guess it's only a matter of time before SRM the will be out of business if they don't move with the times and sell more affordable products.

if that's your thought process, why not get the 4iii, which does everything the stages does for significantly less?

re SRM, why would they be out of business? they are at a different end of hte market to stages. they're the performance king.there are loads that still value that. You now have a bunch of stages copycats coming out with the same type products, same price points. they are the ones that are going to struggle to fist differentiate, and then survive. not everyone wants the cheapest with loads of limitations

Inquitus

mossym wrote: »

snip

My stages reads consistently with my powertap, and it's a much better solution imo. Most people don't have a significant L/R imbalance and its generally linear, obviously there will be outliers and it will not be perfect for everyone.