Logitech Ultimate Ears Personal Reference Monitor Custom IEM Review: Your Sound

COMPARISONS

Logitech Ultimate Ears In-Ear Reference Monitors (IERM): While these two share many characteristics, they are indeed different in many ways.  The IERM has a similar presentation and soundstage space of the PRM, but the IERM midrange is a bit more forward and not quite as spacious or 3D.  With more upper midrange emphasis, the IERM pulls vocals forward in comparison with the PRM, but this could change with different PRM tuning.  Both image very well, but the PRM is superior as well as having a cleaner and clearer presentation and sharper focus.  Detail levels are higher on the PRM with better instrument detail as well as recreation of black space.  Clarity is similar between the two even though the IERM is more emphasized in the “clarity” part of the spectrum, which is a result of the better focus and higher resolution.  Note attack and decay is a bit slower and therefore more natural on the PRM, especially in the treble where the IERM can be a bit too quick on the attack and decay taking away from the smoothness of the presentation.  While I have issues with the IERM treble and less than perfect tracks, the PRM is much more forgiving.  When you combine improvement of the PRM over the IERM the result is a more realistic, natural, and organic sound.  While the IERM is purpose built for recording engineers, the PRM should please those that want a top notch personal listening experience.

NT-6 with Whiplash Hybrid V3: This comparison was performed using the NT-6 with the Whiplash Hybrid V3 cable to close the gap in price.  The V3 cable changes the note decay resulting in a more organic and natural sound while taming the upper end.  Even with the cable the NT-6 V3 is brighter and more mid-forward than the PRM with less warmth.  The NT-6 V3 presents a clearer, slightly more detail, but the detail presented has better focus and the details are in higher definition.  Treble notes are more prominent on the NT-6 V3, closer to the IERM in quantity, but sound more natural due to a longer decay and overall smoothness.  The NT-6 V3 can sound a bit hot in the upper vocal range in comparison with some sources and tracks.  Bass quantity with my PRM tuning is similar but warmer, however the NT-6 bass has more emphasis down low that can sustain sub-bass rumbles longer as well as additional headroom.  The NT-6 V3 is more dynamic and in comparison with the more relaxed and forgiving PRM.  With a slightly larger, more 3D soundstage, the PRM gives a better sense of space.  Images of the PRM is superior and layering is similar, but the NT-6 presents more detail within the layers.

Both perform at very high levels and the differences come down to your listening preferences and usage.  The PRM is easy going with its more laid back, forgiving presentation while the NT-6 V3 is more aggressive and revealing.  With the PRM you give up a slight bit of clarity and resolution for a more organic sound while the NT-6 V3 gives you the details in stunning clarity.  Essentially, the PRM is more focused on the overall presentation while the NT-6 V3 presents the instrument details with more of a focus.  Both are musical in different ways and perform at high levels, but the PRM is a better all-around daily listening CIEM while the NT-6 would excel as a tool for dissecting music or those that don’t want to miss a thing.

Spiral Ear SE 5-way Reference: Considering I used the 5-way for comparison during my tuning session, the PRM sound signature is close.  Both have a spacious, layered presentation, excellent imaging, and an overall organic sound with a very natural tone.  The 5-way presentation changes quite a bit with each track while the PRM is more consistent with a larger space on many tracks.  Note decay is very similar, although the 5-way can sustain notes better, but the attack of the 5-way is slightly more aggressive resulting in a more dynamic and punchy sound.  Detail levels and resolution are higher on the 5-way, however the PRM is very close.  Tonality is a bit different as the PRM upper midrange in general sounds a bit more natural, however the changes of the 5-way seem to change due to the tracks themselves, so the issue is most likely due to the recordings and not the 5-way.  Transparency is quite similar, however due to the ability to change more with tracks and superior dynamics, the 5-way edges out the PRM.  Coherence of both is top notch.

The bass capability is greater with the 5-way as is quantity making the PRM sound more neutral and “reference” than the 5-way.  The mid-bass region isn’t too far off, but the 5-way is warmer.  The midrange is quite similar, although the 5-way has better layering and the size of the presentation changes more with each track.  As stated, the upper midrange of the 5-way changes quite a bit making comparison difficult.  Sometimes the 5-way sounds off in this region vs. the PRM and other times it sounds better, it just depends on the track.  By themselves, both are excellent.  The treble of the 5-way extends further and has a bit more air and has a very nice PRAT, although the PRM is no slouch.

These two are close in many ways and could be considered competitors.  Both have strong points.

The last comparison in the above table will be one of the biggest determining factors in the purchase of either.  If I had both to choose from and listened non-professionally, the decision is a difficult one.  A case can be made either way for professional use: consistent sound (PRM) or a CIEM that will reveal the true nature of the track (5-way).

Heir Audio 8.A: The 8.A has a much more intimate and mid-forward presentation along with much more bass that gives the presentations a greater sense of power and dynamics compared with the more laid-back and neutral PRM. Overall soundstage size is larger with the PRM and while the 8.A has a good amount of ultimate width (headstage), the PRM is a good deal more spacious.  Depth and height of the presentation is superior with the PRM and in direct comparison recreates a more accurate sounding space.  With better imaging and a sharper focus of instruments within the soundstage, the PRM presents has better instrument separation as well as a clearer and more coherent presentation.

As mentioned, the 8.A is more dynamic and punchy and a good deal more capable in the bass region with a much stronger emphasis, even if the bass was tuned all the way up on the PRM.  The bass region is controlled better on the PRM resulting in better texturing, if only by a bit.  Midrange quality is close between the two, but the PRM has a bit better layering with a smoother note.  The upper midrange through the treble of the PRM sounds flatter and more balanced than the 8.A, which has an upper midrange/lower treble bump and then decays in quantity.  While the 8.A treble quality is nice, the PRM treble decay is more natural but the more aggressive leading edge can result in a less forgiving treble, although the PRM has sharper S’s.  Bass and midrange note attack is close, however the 8.A has a bit quicker leading edge while the PRM decay is a bit shorter than the 8.A, which to my ears sounds more true to life.

Overall, the presentations are quite different and the choice between the two comes down primarily a decision between a neutral, laid back and spacious sound vs. an upfront, punchy, and bass enhanced performance, not to mention the price difference.  Also, while the PRM fit, finish, and artwork is good, the 8.A is spectacular.

EarSonics EM4: The PRM is more laid back and open sounding than the more mid-forward, punchy, and bass heavy EM4.  Spatially, both are enveloping, although the PRM has a larger space with better imaging.  The PRM has a cleaner presentation that is more forgiving across the spectrum, which is readily apparent playing well recorded music in the upper midrange and treble region. Coherence is better with the PRM, and note attack and decay are more natural with the PRM leading to a more believable presentation.

The EM4 has more bass quantity from deep bass through mid-bass, however the PRM bass quality is superior. While the PRM can be tuned for a sound that is quite close to that of the EM4, I don’t think the bass of the PRM can have the same impact of the EM4.  Midrange presentation is quite different with the EM4 placing vocals up-front and center while the PRM is more laid back.  The EM4 is brighter than the tuning of my PRM, but both have nice treble decay.   The treble area of the EM4 is less sensitive to sources/amps than the PRM, but with the right combination, the PRM outperforms the EM4 with a more natural presentation and more true-to-life note decay.

The PRM provides a cleaner and more balanced sound with a laid back presentation in comparison with the more up-close and personal EM4 that offers more bass and punch.

M-Fidelity SA-43: With a similar sound, the SA-43 is a bit more laid back and sounds overall smoother than the PRM.  With the presence switch off, the usually laid back PRM sounds forward in comparison while the presentation is similar with the SA-43 presence switch on.  However, with the switch on, the tone of the SA-43 changes and the PRM sounds slightly more natural.  While the PRM is spacious, the SA-43 is more so with as good of a 3D presentation, however the PRM images a bit better.  Clarity is in favor of the PRM in part due to a bit more analytical sounding note.  The PRM technically beats the SA-43 in speed, detail, and overall resolution within the soundstage as well as having slightly better dynamics.  Both are very transparent and coherent.

Bass quantity of the SA-43 with the bass switch off is at about the same level as the PRM, except the PRM extends deeper and has slightly better layering.  When the SA-43 bass switch is on, there is a tradeoff of quantity for control, however extension improves, equaling the PRM.   The PRM is a bit warmer than the SA-43 with the switch off, and vice versa with it on.  With a comparatively more forward midrange, the PRM has more of a focus on vocals with easier to hear details.  The upper mids of the PRM are also more forward, giving a brighter and more lively presentation while the SA-43 has a better balance from the midrange through the treble.  In the treble region both present similarly, although the SA-43 treble is slightly smoother, if just by a bit.

Both of these CIEMs can be tuned in various ways, one before customization, and one after.  The tuning of the SA-43 is done by switches giving you 4 sound options while the PRM has a much larger range for the tuning, but once you pick your tuning, that’s it.  Technically, the PRM equals or outperforms the SA-43 in most every technical characteristic except soundstage size and space.  Here is a summary of how they compare:

JH Audio JH16: With an enhanced deep bass and bright sound, the JH16 is more analytical sounding than the PRM, which is organic and natural.  While the tuning of the PRM can result in a closer match, the JH16 sound can’t be replicated by the PRM.  The JH16 is more forward than the PRM and the overall soundstage isn’t as 3D, although width is similar.  Imaging, coherence, and transparency are better on the PRM, speed and clarity are about the same, and the JH16 is faster, has more bass rumble and dynamics.  Instrument detail levels are similar but the PRM conveys more information within the soundstage.  The PRM is more forgiving.

The bass of the JH16 is a good deal more enhanced and forward with a faster note, but can also reverberate more than the PRM.  In comparison, the JH16 has pounding bass compared with the fairly neutral and not as warm PRM.  The more mid-forward JH16’s analytical note gives a sense of more detail within the midrange, however the detail levels are similar.  While the JH16 has a liquid midrange, the PRM sounds more organic.  The treble of the PRM is much smoother than that of the JH16, as the treble could be somewhat harsh in direct comparison with the PRM. If you are looking for a more analytical sound with enhanced bass, or you listen to pop music, the JH16 is for you.

If you want to tune the bass, midrange, and treble of your monitor and are looking for an organic sound with a more 3D presentation, the PRM is it!

Rooth LS8: The LS8 is more mid-forward with enhancements in both extremes of the frequency spectrum giving a more exciting and intimate presentation in comparison with the organic, natural, and laid back PRM.  Imaging is better with the PRM, which also has a larger and more 3D soundstage.  Dynamics, instrument detail, and clarity are superior on the LS8, if just by a bit, while the PRM bests the LS8 in transparency, coherence, resolution within the soundstage, and note decay.  Speed is about the same between the two and the PRM is more forgiving due to the 6K peak of the LS8, but the LS8 is more forgiving of rough and grainy mids.

Bass of the LS8 is more forward, punchier, enhanced, and warmer than that of the PRM but does give up some in control for the enhancement, resulting in a higher quality presentation from the PRM.  Continuing from the bass, the midrange is also more forward and liquid with more instrument detail while the PRM is analytical and laid back in comparison.  In the upper midrange and lower treble region the LS8 is more enhanced with a smooth and liquid treble above that while the PRM has a different upper midrange/treble balance.  While the PRM is more analytical, imperfections can hide in the comparatively laid back treble presentation.

If you want a natural and organic sound, the PRM is the way to go while the LS8 provides a dynamic and exciting presentation with enhancements on both ends of the spectrum.  The LS8 gives a more immediate presentation that focuses more on individual instruments with a very good presentation, and conversely the PRM has more of a focus on the entire presentation, although the individual instruments are still very high in quality. Technically these two are fairly close, but the PRM does pull ahead, as it should for the price.

ACS T1 Live!: The T1 Live! has a similar sound signature to my PRM tuning, but with some minor differences.  The T1 Live! is a bit more forward and brighter, but they share a similar tone and organic presentation.  Technically the PRM outperforms the T1 Live! in every technical category, however, the differences are not huge.  The T1 Live! is a slightly underperforming, more forward PRM, at least with the tuning I chose.  You could tune the PRM to sound just like the T1 Live! if you wanted.  Bass is similar in quantity and the ability to rumble, but the PRM is slightly superior in the midrange and treble as the PRM has better clarity, especially with complex tracks.

The decision comes down to how price, availability, how important tuning is to you, and if you are willing to pay for better technical ability of the PRM.  Not to mention the silicone shell of the T1 Live! that provides better noise isolation.

Hidition NT-6 Pro: The NT-6 Pro presents an exciting, amped up performance with its enhanced deep bass and treble while the PRM presents a relaxed and organic performance.  One of the first things I noticed comparing the two was the NT-6 Pro has a slightly faster note that, when combined with the upper region really pulls all the details out to the forefront in contrast to the organic, laid back presentation of the PRM.  Detail, resolution, speed, and dynamics are higher on the NT-6 Pro while coherence and transparency are similar and both exceptional.  The soundstages are quite similar in size and shape even though the presentation is different, with an ever so slight edge in imaging going to the PRM.  Both have a liquid presentation and PRAT is good, however they are both different as due to the note speed difference.  The PRM is more forgiving of poorly mastered tracks and is easier to find a good source.

Bass of the NT-6 Pro is enhanced in the lower registers, rumbling quite a bit more than the PRM with deep bass, and while the PRM isn’t bad in the bass region, the NT-6 Pro can output more bass with similar quality.  Warmth goes to the PRM, although the NT-6 Pro isn’t too far behind.  The midrange of the NT-6 Pro is more forward than the PRM with a more intimate sound that picks apart the presentation, delivering plenty of easy to hear detail vs. the presentation focus of the PRM.  The upper midrange of the PRM is excellently balanced with the rest of the spectrum, and while the NT-6 Pro has a boost in the region, it still manages to sound tonally right.  There is a good deal more treble presence with the NT-6 Pro, and detail levels are higher.

These two complement each other, with the PRM focusing on an organic and natural presentation while the NT-6 Pro does fun with mind blowing clarity.  The PRM can’t be tuned to the NT-6 Pro levels, and the difference in note separate the two further.  Both are very different and excellent in their own ways.

Unique Melody Platform Pure | PP6: The PP6 is more spacious, airy, and bright compared with my tuning of the more mid-forward PRM.  Notes are thicker on the PRM resulting in the PP6 having a cleaner and clearer sound.  Detail levels are similar, as is resolution, but the PP6 images better and has a wider and deeper soundstage.  Transparency and coherence are similar, but the PP6 has better dynamics and speed.  While both are smooth, the track determined which was more forgiving.

Keeping the bass boost switch in the off position still results in the PP6 having more bass than the PRM in quantity, which is tunable on the PRM so quantity could be similar, but the PP6 can sustain bass notes better.  Bass quality is similar between the two.  The PRM is warmer than the PP6, and while that is tunable, there is warmth from a thicker note.  The midrange is divergent as the PP6 strikes a good balance between laid back and forward while the PRM is more forward, bringing vocals closer to you, but the smaller soundstage and closer midrange make it sound a bit small in comparison.  The upper midrange of the PRM seems a bit artificially boosted in comparison with the PP6 and without using a PRM tuning box with the PP6 present, I am not sure if the gap can be closed.  While the PP6 has more treble energy than the PRM, the quality of the treble is superior with the PP6. There are times when in direct comparison, one CIEM sounds much better than the other, and this is the case here as the PP6 sounded more natural and realistic to my ears due to the differences in upper midrange.  This is not an issue with the PRM vs. other CIEMs.

Both of these CIEMs offer something unique as the PRM can be tuned to your preferred sound signature while the PP6 uses an active crossover, 6 amps, and an internal DAC along with adjustable bass boost.  If you want a more mid-forward sound, the PRM is a good buy, and if you want a U shape with a clean and clear sound, the PP6 is excellent.

Fit-Ear PS-5: With a more bass leaning, warmer, and powerful presentation, the PS-5 is more mid-forward than the cleaner and more spacious PRM.  Overall space of the PRM is larger, but the imaging and presentation depth are better with the PS-5.  Clarity is a bit better with the PRM and while detail level and resolution are close, the PS-5 articulates detail better, in part due to the more up-close presentation.  The coherence/integration of the drivers is better with the PRM as is transparency by a bit while dynamics are better with the PS-5.  Note attack/decay is close, but the PS-5 gets a slight nod overall, and is more forgiving bad tracks.

Bass capability of the PS-5 is significantly better than the PRM, but it isn’t necessarily too much more enhanced.  Depending on the track, the PS-5 can sound similar in the bass region, but when there is a significant amount of bass in the song, the PS-5 pulls away from the PRM in terms of quantity.  Both are warm, but the PS-5 is a bit warmer due to the thicker note.  The midranges are divergent, as the PS-5 is more mid-forward with a more engaging presentation compared with the PRM’s vast presentation like being in the audience.  The linear treble of the PS-5 shows that the PRM treble has peaks in comparison.  From a quality perspective, the PS-5 is smoother yet still is more detailed.

These two heavyweights take different approaches to their great sound.  The PS-5 is more bass heavy, smoother yet as detailed, and presents in a more up-close way while the PRM is a tad bit clearer, more neutral, and can be tuned to your liking, which weighs big on the buying decision.  However, regardless of the tuning, the PRM will never have the bass weight or treble extension of the PS-5.

SOURCE MATCHING

Portable Sources, DAPs Clip+: Paired with this high performance CIEM, the Clip+ shows its price by holding the PRM back in dynamics and depth of presentation.  The bass isn’t as impactful and not quite as full as with the iPhone 5, and spatial size of the presentation is constricted.  It isn’t a bad source per se, but you can do a good deal better with an iPhone 5.  3/10

iPhone 4S: The iPhone 4S sounds OK with the PRM with decent soundstage size and good imaging, but the bass is weak and the presentation sounds a bit smeared, lowering the clarity level.  Notes are a bit harsh in comparison with the Clip+.  2.5/10

iPhone 5: The iPhone 5 is a good match for the PRM considering it is a phone.  The bass is ample, the presentation is spacious, and the dynamics are slightly better than Clip+, and about on par with the RoCoo BA.  Detail levels are on par with the Clip+, and both leave the finer details of music out.  There is room for improvement, especially in detail levels, but overall the iPhone 5 is a good choice considering it is a phone.  5/10

RoCoo BA: The RoCoo BA performs close to the iPhone 5, however it has a bit smaller presentation which leads to a little less clarity than the iPhone 5.  Detail levels are higher than the iPhone 5 and the attack is a bit quicker.  The iPhone 5 has a slight bit more upper midrange emphasis while the BA has more treble emphasis, but it is close.  Bass between the two isn’t too far off, but the iPhone 5 extends a bit further.  If you can carry an iPhone 5 around, the RoCoo BA is a device I find hard to recommend unless you want it for the size and storage, or if you want 2 devices.  5/10

801 (with GAME card): The 801 with GAME is a step up from the RoCoo BA and iPhone 5 with better detail, dynamics, a more natural tone, larger space, and better clarity.  Combining the improvement in all the attributes, the 801 with GAME is a nice step up and provides a very natural presentation.  The 801 doesn’t have the same treble issue I had with the IERM.  8.5/10

Astell & Kern AK120: Overall, the presentation is very good and a combination worth listening to as there is a nice recreation of the 3D space within tracks, dynamics and punch are there, and the level of detail is high.  Compared with the DX100, performance lags slightly with less clarity and resolution as the DX100 is more precise and fine nuances within songs are easier to hear.  However, the AK120 still sounds extremely good and without the comparison, it performs exceptionally well.  9/10

DX100 (1.2.7 firmware): Fantastic spaciousness along with great clarity and a natural note articulation result in a very musical presentation making the DX100 an excellent match.  Compared with the 801 with GAME, the DX100 has a bit more spaciousness, clarity, and resolution.  10/10

Portable Sources, DAPs with Amps

iPhone 4S ->

627: Pairing the 627 with the iPhone 4S does improve the sound with a smoother, larger presentation, however the limitations of the iPhone 4S do inhibit the soundstage.  The presentation is still not the smoothest, and with the lack of depth, the presentation sounds flat in comparison to how the PRM can sound. 3.5/10

iPhone 5 (headphone out) ->

Arrow 4G: Retaining the presentation of the iPhone 5, the Arrow doesn’t change much except smoothing notes out, making the iPhone 5 sound a bit grainy in comparison, and adding a bit more depth to the presentation, but not much. 5.5/10

Stepdance: The SD adds a bit of dynamics and more of an upper midrange emphasis to the PRM, but the changes aren’t necessarily improvements.  There is hiss that isn’t there with the HPO.  The score was reduced by 0.5 for the hiss.  4.5/10

Modded iPod -> EHP-O2: The O2 sounds good and true to the recording with the PRM.  The soundstage size does constrict the PRM compared with higher end sources and there is a bit of a haze within the soundstage, but there is a naturalness to the sound. 4.5/10

Shonyun-306: With a more mid-forward presentation than the O2, the presentation doesn’t sound quite as natural.  The upper midrange through the treble is not very smooth leading to a fatiguing presentation, even after a short period of time. Not a good match.  1/10

Neco V2: Compared with the O2, the V2 is smoother, a slight bit more forward, but more natural sounding with a slight bit larger overall soundstage.  Bass quantity and control is similar between the two.  There is a slight channel imbalance at very low volumes which reduces the score 0.5.  4.5/10

uHA-120: The 120 images quite well in a nice sized, 3D soundstage.  Compared with the V2, the 120 is a slight bit rougher in the treble, however it does image better and provides a larger, more 3D space than the V2.  Bass on the V2 is slightly more powerful with similar control, and the V2 has a bit cleaner and clearer presentation.  The depth of the presentation improve the overall sound, but the V2 is slightly better in instrument detail. 5/10

Pico Slim: The PS is bright by nature which can be heard vs. the uHA-120.  Bass of the PRM is neutral making the other amps I used for comparison testing sound warmer.  While the midrange and treble are good, they aren’t a step up from the uHA-120 and the treble is actually a bit rougher.  Soundstage size isn’t on par with the 120, although imaging is good. 4.5/10

Stepdance: With an excellent presentation of space and a very natural sounding note.  Dynamics are great and the Stepdance gives the PRM nice punch down low while still keeping the quality superb.  The midrange and treble are also excellent and match quite well with the PRM.   There is hiss, which reduced the score by 0.5.  7.5/10

Cruise: The Cruise is a punchy amp that has a fast note, and with the PRM this is no exception.  The presentation is more aggressive than the Stepdance, but the quality is not lacking in any way.  With more upper midrange emphasis, the Cruise sounds brighter than the Stepdance and not as tonally accurate.  The Cruise does allow the PRM to accentuate detail and keep up with the fastest complex tracks with ease.  Another issue with the Cruise is the slight amount of hiss, which does lower the score by 0.5. 6.5/10

627: The 627 takes a step up from the other amps, offering excellent clarity, a large soundstage space, and excellent imaging.  Compared with the Stepdance the entire presentation is cleaner and the bass is controlled better.  Spacious tracks improve in size more than the other amps and the overall presentation is detailed yet smooth with better layering.  9.5/10

801 line out -> Arrow 12HE 4G: The 4G pairs with the PRM quite well, providing a bit more air and brightness to the HPO of the 801 as well as a more expansive soundstage.  The 801 is more forward with less soundstage depth, so the presentation sounds a bit stuffy and slightly compressed in comparison, however the 801 does have more deep bass than the 4G.  9/10

Stepdance: Pulling the soundstage back a bit compared with the 801 HPO, the brighter SD doesn’t add much in the way of quality, and the 801 sounds more weighty.  Tonally, the 801 HPO sounds a bit more accurate, and there is hiss on with the SD, which reduced the score 0.5.  Overall, the SD isn’t bad, but if you have the GAME card with an 801 there is no real reason to use a SD.  7.5/10

Desktop Sources D1: The D1’s direct competition from a sound quality perspective is the DX100, and the D1 is different than the DX100 in that it has a bit thinner note giving it an analytical feel vs. the more organic DX100.  Overall, the quality of the presentation is very  high, however the DX100 images a bit better and had a larger, more 3D space.  9.5/10

Source Summary: Lower end sources and amps restrict the soundstage space and detail of the PRM, typically resulting in less overall clarity within the presentation.  When high quality source components are in the chain, the PRM will come to life with better dynamics, incredible spaciousness, and very high levels of detail.  While the PRM will play nice with some lower end sources, if you are going to spend on the PRM, you should have the source chain to shine.

page 1: Write-up Page

page 3: Summary