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Polk T15 Bookshelf Speaker Review
- Thread starter amirm
- Start date
Well, about that…
After sitting down and thinking about how I could possibly add a feature to Loudspeaker Explorer that would allow the user to "offset" the angle for all plots (e.g. plot everything at a 20° vertical angle for the Polk T15), I realized that's not actually feasible with the datasets you provide, because they are missing diagonal angles.
For example, let's say I want to generate a new spinorama centered on 20° vertical. In order to do that, I need to recompute things like listening window, early reflections, and predicted in-room response. Now that's fine, I can write code that does that. The problem is, in order to, say, compute the listening window, I need off-axis angles like, say, 5° horizontal. Therefore, relative to the original data from your dataset, I need the 20° horizontal, 5° vertical diagonal angle. But sadly, the datasets you currently publish don't have that.
You mentioned some time ago that the Klippel software has a VACS export option. I suspect this particular export would contain diagonal angles? That would solve the problem. If that's not too much to ask, would you consider publishing the VACS for this speaker (Polk T15) so that we can experiment with the data and see if something interesting can be extracted from the additional information?
OP
- Thread Starter
- #183
Why can't you interpolate from adjacent graphs/measurements?
Mmm. I guess I could, but I would have no idea if the interpolation is even remotely accurate since I don't have the "ground truth" to compare it to. I suspect it actually wouldn't be accurate, because you regularly show 3D balloon plots in your reviews that display "interesting" behaviour happening at diagonal angles that naive interpolation surely wouldn't predict. Vertical contour maps also show quite unpredictable behaviour for most speakers, which is another reason to suspect interpolation error would be quite high.
Basically, I think interpolated data would be highly suspect due to the complexity of the sound field produced by a typical non-concentric multi-way speaker.
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infinitesymphony
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I was reviewing Genelec's monitor setup guide and this image caught my eye:
The ITU-R BS.775-1 standard recommends a maximum of 15° inclination. The 20° and 30° inclinations mentioned by some in this thread would go beyond this recommendation.
The ITU-R BS.775-1 standard recommends a maximum of 15° inclination. The 20° and 30° inclinations mentioned by some in this thread would go beyond this recommendation.
maty
Major Contributor
My thoughts on these speakers are that they are probably good bonfire wood lol.... but I did hear the Polk Signature S15 at Best buy and thought they sounded pretty neutral so I'm curious how they would measure. I've always had a soft spot for Polk since they were my first real speakers, I had the Polk Rti 100 which were pretty good speakers at the time.
Hi All,
Got a pair of T15, and to my ears it has very good bass extension, but lack in mid-highs, thus reflecting the FR measurements.
Looks like it would be enough to invert tweeter’s phase in order to reduce the hole in the mids. Any of you made a FR measurement under these conditions? To your knowledge, are there any tweaks for the T15’ s crossover achievable in some website?
Greetings from Italy
Got a pair of T15, and to my ears it has very good bass extension, but lack in mid-highs, thus reflecting the FR measurements.
Looks like it would be enough to invert tweeter’s phase in order to reduce the hole in the mids. Any of you made a FR measurement under these conditions? To your knowledge, are there any tweaks for the T15’ s crossover achievable in some website?
Greetings from Italy
mhardy6647
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I don't know (and, frankly, I rather doubt it), but perusal of the Polk Audio forums would be a good place to start!
https://forum.polkaudio.com/
BillGrimm
Member
Looks like you have upgraded the veneer on your 10Bs. I need to do something like that. The oak on mine is peeling off. They still sound amazing, though!
Prana Ferox
Addicted to Fun and Learning
Nah, these are stock. I think the quality of the veneer shifted a good bit over the course of the original Monitors' production run, I've seen some that were pretty unpleasantly vinyl.
I just finally found this review. I have these as desktop speakers currently. The thing I found with them is that mine seem to have a huge resonance spike right around 133hz that makes them unbearable for music. I found it while doing a manual freq. sweep. I think it's the cabinet resonance? In windows I've got an EQ with 133hz pulled down and they are much more enjoyable. The question is that I'm surprised that didn't show up in this review? Maybe mine were built differently?
The cabinets vary from speaker to speaker and sometimes a cabinet is not glued correctly or has poor tolerances and resonates. I used to provide warranty service for Energy and KEF and cabinet issues where not common but not uncommon. We always had a few a year but not so much with KEF. You probably got a bad cabinet. Sometimes a woofer will have a issue too. By frequency sweeping you should be able to locate the fault.
Right on, thanks.
Not saying you aren't right but if you measure in indoor enviroment a 133Hz (2,57 meter wavelenght) spike can most easy be room boundary or other surface reflections and if that's the case its not the anechoic output of your T15, so in that regard measuring in indoor enviroment below say 500Hz be carefull make any conclusions if your sample is different to Amir's sample or if its cabinet issues, also because the T15 curves we see measured here is more or less poor performance or non ideal so expect not acoustic output is dream sound or of reference class
..Not saying you aren't right but if you measure in indoor enviroment a 133Hz (2,57 meter wavelenght) spike can most easy be room boundary or other surface reflections and if that's the case its not the anechoic output of your T15, so in that regard measuring in indoor enviroment below say 500Hz be carefull make any conclusions if your sample is different to Amir's sample or if its cabinet issues, also because the T15 curves we see measured here is more or less poor performance or non ideal so expect not acoustic output is dream sound or of reference class
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I had thought that maybe the table was contributing so I floated them on socks to no avail. It sounds like the resonance is coming directly from the speakers since I'm near field (desk use). I've wondered if there's supposed to be insulation on the inside that isn't present. With them being front ported I didn't think the wall behind them would contribute, I step them away a few inches though. idk. If I get some spare time I'll set them on top my towers in the living room to change the environment and see if they sound the same.
I've been tempted to buy a calibrated mic for some profiling, for fun.
Having 3 pairs of speakers I think I've come to be able to identify cabinet resonance. I also have Polk T50 towers and while I do enjoy their character the cabinet resonance is apparent (nowhere near as bad as T15, it's just that i can easily identify it). Stepping up to RP-260F as replacements, that T50 resonance I can tell was removed. The RPs have their own resonance but it's much more subdued and at a lower frequency.
I had often thought about (just for fun) gluing/screwing plywood to the outside of the T50s just to hear what the effects would be. The reason I say this as when listening to them I would constantly be visualizing the cabinet resonating and what it would sound like if I did that.
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the text on that tweeter is definitely not level. Or maybe the entire tweeter isn't level.
I have 4 T15 (2 as part of the 5.1 set, 2 purchased later). They're turkeys, even at -20 degrees vertical axis, the reflections can't redeem them. There's still a hole in the upper midrange. Measurements confirm they're performing badly. I didn't think they were even very good as surround/Atmos speakers.
I think the T50 is pretty good, the T30 center speaker is OK. I've replaced the T15s with ancient Infinity RS1000s and CSW Model 17s. Much better.
I think the T50 is pretty good, the T30 center speaker is OK. I've replaced the T15s with ancient Infinity RS1000s and CSW Model 17s. Much better.
ClassicGuy
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How can this be called AudioScienceReview if object measurements are completely disregarded in the final rating (and yes, I consider panther the final rating). The measurements are terrible.
If measurements don't match subjective listening to this extend, we should start questioning what we are measuring.
If we think Polk has found a new magic formula to make speakers sound good at 20V axis, then it's a scientific curiosity. All the more reason to investigate further and measure at different axis.
If measurements don't match subjective listening to this extend, we should start questioning what we are measuring.
If we think Polk has found a new magic formula to make speakers sound good at 20V axis, then it's a scientific curiosity. All the more reason to investigate further and measure at different axis.
ROOSKIE
Major Contributor
Well if you measure someone to be 5 feet tall, the data suggests they will not be able to slam dunk a basketball as hardly anyone that height can.
However they may in fact be able to do so as some rare 5 foot people can and do.
Data and measuring is not the final word in science or anything.
Now I realize that in a different way you could collect more data to determine with more accuracy who can slam dunk, however it will never be without meaningful variation.
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