Periodic Audio Discussion Thread

Discussion in 'Two Channel Hi-Fi Equipment' started by Eric SVL, Apr 29, 2018.

  1. Eric SVL

    Eric SVL Active Member
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    [​IMG]

    Thought I'd start a thread for discussion of http://periodicaudio.com/ headphones and amps.

    Currently, there are three models of in-ear monitors available, and one amplifier. All three models share the same design, with the driver material producing the sonic differences between them.

    PA Headphones.png

    Post reviews and news of upcoming products here.
     
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  2. Eric SVL

    Eric SVL Active Member
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    Periodic Audio Magnesium In-Ear Monitor Review

    Frequency Response: 20 Hz to 30 kHz
    Impedance: 32 Ohms nominal
    Sensitivity: 101 dB SPL at 1mW in ear
    Power Handling: 200 mW continuous
    Peak SPL: 121 dB
    THD: Less that 1.5% THD at 1mW

    Full specifications: http://periodicaudio.com/Mg.html

    As a child I was told not to put things in my ears, but I'm glad I ignored that suggestion this time.

    Thanks to tesseract for the suggestion to try these. I'm really liking them, however at first I was very skeptical of the sound. I'll explain why I changed my mind. This is my honest review of the Periodic Audio Magnesium in-ear monitor. It is going to be different from other reviews out there, because I'm going to describe not just my impressions, but how I use them on a daily basis. I won't be going heavy on the audiophile terms, either, opting more for the layman's approach.

    As most of us are concerned with the sound output, I'll only comment briefly on other aspects. The polycarbonate construction feels inexpensive, but solid. The designer says the materials were chosen due to their very low resonance, and I have no reason to doubt him. Plus, I would prefer to not have a heavier material weighing on my ears. I was able to achieve a good ear seal and comfort for listening sessions lasting up to 2 hours with the small foam tips provided. I had no such luck with the others, and there are many included to fit various ears. I wear them with the cord exiting upward and going over and behind my ear.

    I have been listening to these with an LG V30+, the phone with the beefed up amp and special DAC.

    Bass:

    The sub bass was a pleasant surprise: it is powerful and extends to below 10 Hz! I like to listen to soundtracks. Tracks from the Mass Effect and Transformers series' have a hard-hitting cinematic feel. This type of music is a very pleasing, dynamic experience on these headphones. Bass is very strong and anchors the bottom end of movie soundtracks and other bassy songs well. Out of the box they may be a bit too sub bass heavy for rock, but a little EQ fixes that. I've read that the Titaniums have even more powerful bass, and it would be interesting to see how the Berylliums refine this sound further.

    Because of their response, these do well at low volumes due to the Fletcher Munson curve. That is, we like a bump to the lows and highs at low volumes, but we tend to prefer our frequency response curve to flatten out at higher volumes or the bass and highs end up being overpowering. That is my experience with these: I found myself turning them down often due to fatigue.

    Mids:

    In my experience so far, electronic music sounds good out of the box. However it's when I fired up some rock music, which I can equate to real life sounds, that I noticed vocals, bass guitar, and drums do not sound as powerful and forward as I would like. Vocals are clear but more intimate sounding.

    Several reviewers have commented that they think the lower mids are a little recessed. I agree. As the response of any particular frequency range is relative to the response of the other frequencies being produced, the main cause for the comment is the bump in output in the bass and treble - of course the mids are going to sound recessed by comparison. A slightly flatter curve would better balance the package, in my opinion.

    Using the DSP Pack in PlayerPro, I ended up taking about 2 dB out of them at 64 Hz. I've never had to do that with any headphone or speaker before - usually it's the opposite! Takeaway: these have bass to spare. Kick drums have a very solid thud and you will feel the weight of them on your eardrums, even after this change. No worries there. This change was mainly to make some room and bring clarity to the midbass, which I felt was being a little crowded out.

    And that leads me to my biggest problem with the sound of these headphones - the sharp rise centered around 3 kHz. This combined with the rise in the bass crowds out the midbass, midrange, and also slightly the "sparkle" I like to hear at the top. I reduced 4 kHz output by 2 dB using the EQ and things sound much more natural and balanced. My adjustment options don't give me the ability to adjust 3 kHz, so with another EQ I could potentially improve the sound further.

    There is a rise in impedance at 3 kHz, therefore it is possible that the design tries to compensate for this reduced output and overshoots its target, but I'm merely speculating and it could be intentional.

    Overlay of FR and impedance:
    Mg Z+FR.png

    Highs:

    The top end doesn't quite strike me in terms of realism like the planar magnetic tweeters I auditioned in some Chane speakers, but they do very well (and that's not a very fair comparison). Listening to various soundtracks from movies and video games, highs are clear and detailed. These will reveal flaws in recordings: a listen to The Offspring's Smash album revealed some static-type noise in the recording of the vocals that I hadn't heard before, and I've listened to this album many times, but never with an IEM.

    To my liking however, they sounded a bit tame. Too conservative and a bit congested. Cymbals sound like they are in the next room over. Strings aren't quite "there" yet and if you look at the low output at the right of the frequency response graph you'll see why. So what really gave them some air for me was some extra energy at 8khz and 16khz. Just a 2db increase at those frequences really opened them up.

    No more congestion. Now those strings are really singing. And those cymbals that sounded like they were in the other room, are now in the room with me. Also, the overall sound is less "in my ears", instead sounding more open and less confined. It is more spacious, as if the sound source moved out about an inch. I feel things are fairly well balanced now and non-fatiguing, which is crucial for me. I now find myself wanting to turn the volume UP. That is when I know I have things dialed in - there aren't any obviously offending frequencies. The finale "I Don't Think Now is the Best Time" of Pirates of the Caribbean - At World's End was especially fun and whimsical as was John Williams' Star Wars - The Force Awakens with all of the strings and horns at play in each. I even threw on Carmina Burana - O Fortuna, as performed by the Royal Philharmonic and Antal Dorati (my favorite recording) and it was as epic as ever. The passive noise blocking of the foam tips made the voices during the quiet buildup much more discernable than I've heard before.

    Rock music was much improved, which by its nature is very demanding with all of the details in the midbass and midrange vying for output and the attention of your ears. Amon Amarth's Surtur Rising, Rammstein's Reise, Reise, Korn's See You On The Other Side, Chevelle's Hats off to the Bull and La Gargola, Metallica's Hardwired...To Self Destruct, Papa Roach's Time For Annihilation, and every Tool album (yes, all 4) were rendered excellently. All of the bass guitar riffs, vocals, and drums were at levels that sounded right to me and with plenty of detail. Nine Inch Nails - The Downward Spiral, The Fragile, and With Teeth sounded as good as I've heard with all of the mastery that Trent Reznor puts into his recordings. Even The Offspring - Smash was fun, but this was the only album that suggested I put the 8khz and 16khz levels back to 0 as the recording is on the edgy side already. Overall, I'm not hearing anything offensive, be it sibilance or ringing. Everything sounds pretty tight. This isn't a complete list of everything I listened to but it covers most of it in style and recording quality. The majority of my tracks are either constant 320kbps MP3 or LAME-encoded VBR (Variable Bitrate) MP3 at the highest setting. Double blind testing has shown that between these and their corresponding FLAC rips, people can not tell which is which.

    The reduction in the background noise level (-31 dB with the foam tips) is something I'm really enjoying. It is much easier to listen in to the details, and not a lot of power is needed to reach the right volume levels. I had the chance to take these with me on a flight to and from Chicago and I could listen to music, albeit at higher than normal levels. At this point I could not even hear my Koss KSC75s, so the ear-sealing design definitely has its advantages. At the office, I tend to listen to these at a volume level of 25-40 (same as the KSC75s) on my LG V30+, and they are plenty loud. I would say this level sounds comparable to 75-85 dB SPL on my main system (with subs running hot) which I tend to prefer for movies. I do have sensitive hearing. With the ability to output 101 dB with only 1mW, you will not benefit from exotic amplification here.

    I made the frequency adjustments based solely on my own perceptions, inching things more toward what I felt was a balanced sound. But once I looked at the FR graph provided by PA, my decisions made sense. I effectively flattened the response a bit, creating a more neutral sound where everything sounds clear and nothing is crowded out. I could probably do better with a more detailed EQ, but this is really good as it is.

    My final settings with this particular software, PlayerPro for Android:
    Screenshot_2018-04-25-12-46-01.jpg

    I am not implying that you will need EQ tweaks. You may like them as-is. But it is my duty to report my impressions and how I am actually using them on a daily basis.

    I could imagine more refinement being possible, which I'm sure is where the Beryllium excels. But for $99 and a few simple EQ tweaks, it's going to be very hard to beat the sound you can get from the these. However if I did not have access to a DSP/EQ with at least this level of granularity, I don't think I would keep the Periodic Audio Magnesium.

    My preferences: I don't prefer "laid back" speakers, especially not in the midbass or midrange. My preference generally tends to be a frequency response with a negative slope. That is, a rise starting from 10-20hz that is maybe 6db hot (or 10db with high damping), sloping down to +0db, with the top end adjusted to taste based on room acoustics and volume*, of course. There are a lot of variables, but that is the general trend for me, and research shows that is what the majority of blinded listeners prefer. *Low volume needs a bump to both the low and high frequencies to maintain perceptually equal sound due to the non-linear response of human hearing. See: Fletcher Munson curve.

    A few notes on the "Hi-Fi Quad DAC" on the LG V30: For these headphones, it sounds better in the off position. It may be my preferences, but no matter how much I play with the settings, I only get further away from my ideal sound. Just for kicks, I hooked up a pair of 600ohm AKGs from decades ago. This is where you need that upgraded amp output - I could not achieve my normal listening volume without it enabled. They were just too quiet without the extra power. So what LG is doing here is real and tangible. The DAC may be marketing, but the amp output is no joke. Unfortunately, you can not enable just the better amp without choosing one of three impulse response settings in the Hi-Fi Quad DAC. Each of them alter the sound and after much listening I don't prefer any of them. And, as these are easy headphones to drive, they have enough output to damage my hearing at moderate volume levels from nearly any smart phone today, so while it was interesting to experiment with these features, they will stay in the off position.

    Hopefully by conveying my impressions here you will get a better idea of them. I bought these for my own personal use after getting tired of going through so many pairs of KOSS KSC75s and their failure-prone wire soldering.
     
    #2 Eric SVL, Apr 29, 2018
    Last edited: May 31, 2018
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  3. tesseract

    tesseract Senior Admin
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    Thanks, Eric! I thought the Mg bumped pretty good from the short audition I had. Sounds like they are easy to live with, too.
     
  4. Matthew J Poes

    Matthew J Poes Staff Writer
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    I was impressed as well. Among the best sounding in ear headphones I ever heard.
     
  5. Eric SVL

    Eric SVL Active Member
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    They are definitely going to make your ears happy.

    I will also be adding more music to my list for future evaluations.
     
  6. Eric SVL

    Eric SVL Active Member
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    I made a small edit to my review. I originally compared the bass to my Rythmik subs. After spending some more time with my main system in the new house, I can tell you that comparison is wrong. While the Periodic Audio Mgs have the bass to create a solid foundation for any type of music, they don't compare to my Rythmiks on high damping. Then again, not much does. The MGs are a bit smoother, closer to a low damping setting, but definitely not in a way that would leave you unsatisfied. I think one would say there is more ringing or overhang (some people actually prefer this). That makes me want to try the Berylliums to see how the stiffness of the material affects this.
     
  7. Todd Anderson

    Todd Anderson News Editor / Reviewer/ Senior Admin
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    Eric, great write up / review! Enjoyed reading it... do they feel heavy in the ears?
     
  8. tesseract

    tesseract Senior Admin
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    I have the Be (review forthcoming) and they are comfy, more so than the 1MORE 1001 Triple Driver, which does feel slightly heavy in the ears.
     
  9. Eric SVL

    Eric SVL Active Member
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    Not at all, very light. You will almost forget about them.
     
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  10. Matthew J Poes

    Matthew J Poes Staff Writer
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    Dennis and I talked to Dan wiggins about this. He said that he spent a lot of time on the center of gravity to ensure they sit in the ear nicely. That and the use of light weight materials ensured they would feel very light in the ear. I can say this, only in ear headphones I ever tried that didn’t fall out of my ears easily.
     
  11. Eric SVL

    Eric SVL Active Member
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    I recently came across the following article discussing in-room sound preferences among the public. It is based on research done by Toole and Olive. What they found is very interesting, and leads me to wonder if Dan designed his IEMs around these findings. Compare the frequency response curve of PA IEMs to what follows in the link. I do not know what measurement method Dan uses, so I can't prove that the results are comparable. But the resemblance is striking.

    https://www.innerfidelity.com/content/acoustic-basis-harman-listener-target-curve
     
  12. Matthew J Poes

    Matthew J Poes Staff Writer
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    Hi Eric,

    It’s funny that you say this. I happen to know the answer to the question you ask.

    At AXPONA Dan was showing off his headphones. I was walking around the floor with my head down looking at the equipment. I know Dan but hadn’t met him in person before. Dennis was with me and talking to Dan who introduced himself. I looked up and when I saw his name tag practically jumped back yelling wow I know you!

    Dan went on to explain....no....rant that Harman developed a neutral curve, not a preference curve. That preference is subjective and far more country/culture specific. He told us that his Chinese clients had a certain preference curve they preferred over what westerners preferred. He went on this rant for a while explaining how Toole got it wrong. The contempt in his voice was palpable.

    Such passion in this industry isn’t unusual, so here is why it was memorable for me. Next to Dan’s table was NAD/PSB’s table. Sitting not ten feet from Dan was Paul Barton. Paul was working with the NRC when Floyd ran the lab and Paul helped with these experiments. Paul has since recreated these tests and adopted essentially the same room curve. It goes by the name room feel. This is why NAD and PSB headphones have room feel, it’s a response curve.

    So the answer to your question is that No Dan didn’t design the response to match any of Floyd’s work. He developed it on his home and even goes so far as to disagree with Floyd’s view on appropriate preference curves. That doesn’t mean there aren’t similarities however. I would need to measure a pair to see.

    Harman has actually developed a separate curve for headphones specifically that is designed to match how we perceive speakers in a room. It’s a little different and seems to get updated from time to time.
     

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