- Adding HR to "Plain" MDF MMGs:

• For old MMGs like mine (but that are still unframed), this is the most freaking impressive upgrade I know of, for less than 20 bucks and so little sweat! It was clear from the get go. It has changed with time and, in the process, gotten better "distributed" at 110 hours+ of playback with the Cascade material on. Newer (unframed) MMGs should also benefit grandly with HR, though this remains an educated guess.
   
• In general, and from the beginning, midrange clarity improvements carry the day. To the extent that an instrument or passage remain in this general zone, detail, clarity and textures improve. This seems to be the sweet spot of HRs influence, when compared with Plain. It went from MIDRANGE, MIDRANGE, MIDRANGE!  to, in 100 hours or so, MIDRANGE, Midrange, (BASS & highs)!
   
• It started with shocking improvements in midrange clarity, where a ton of the detail information lies in most music. On the initial listening session, HR even showed some of the midrange detail that I had only found after using P-Frames.  On that first day, having just re-listened to Plain for 3 hours, HR fooled me into hoping it was closer to P-Frames than it really was. Fresher ears the following day showed it was not so. Yet, it was obvious that great improvements had been made by HR. Later, HR lost a little bit of that midrange clarity (and I mean, just a bit). Yet, other things improved along the way.
   
• Bass got better with time. From the beginning, HR's instrumental textures in the typical MMG bass range were always somewhat better than with Plain. Yet, at first, the perceivable bass extension went no lower than "Plain". Later, the bass improved in perceived extension. That extended bass segment of HR vs Plain, seems to reach almost as deep down as P-frames at times, but lacks as much definition and dynamic impact. On "Use Me", Patricia Barber, "Companion" XRCD (FIM) - G2, this transition bacame evident. The upper details of the impressive bass solo passages had more string detail with HR. Later, HR also revealed more of the bottom bass...muffled in detail but now present.
   
• Further an example of the 2 points above is "The Beat Goes On", Patricia Barber, "Companion" XRCD (FIM) - G2. It opens with very strong bass plus a snare drum struck with brush sticks PLUS a drum being brushed. Plain, my MMGs delivered a feeble bottom bass and could not "complete the picture" of the snare drum brush strikes. It was there, of course, there was enough information to know it. As for the other drum being brushed, it was simply made a faint background swoosh. OTH, with HR (broken-in), the bass acquired presence, though softened. The snare drum was clearly distinguished as such. Notably, it was also distinct from the drum being brushed further back; which could now begin to be heard as such, brushing. (P-Frames & PF+HR do much better here). 
   
• Consistently, in that "Companion" disc, on all songs, Patricia's voice was better defined with HR than with Plain; and sharpness improved while loosing some of the excess warmth. In fact, all vocal material whether male, female, choirs,  Broadway musicals, etc. got a nice bump up in clarity and richness of tone. This, despite not letting go of much of the warmth (coloration) that the Plain MMGs can, admittedly, still endear with. This qualitative improvement remained unchanged from the beginning.
   
• At first, the top end, showed no improvements but lost nothing that I could detect vs. Plain. Later, it gained more smoothness than Plain had ever reached. (but not as much as P-frames alone or P-Frames+HR). With HR, the strong violins & string section, which dominate during most of the "Boys from Brazil" theme (Jerry Goldsmith, Telarc SACD) - G1, sounded fairly close to Plain at first. Days later, I realized change was happening with usage. So, I was delighted to discover that HR had gained a welcome bit of influence in cleaning up the strings harmonics. This piece became more enjoyable, as did other similar orchestral passages in G1 and G2 recordings. This kind of improvement at the top end, however, was clearly evident only as long as no strong instrumental forces played along.
   
• HR allows you to raise the volume a few dbs higher than Plain before the loss of clarity becomes as bothersome with some music. It sheds some of the "warmth" (coloration) found in Plain but retains enough of it, that some people may actually like it more [than the cooler precision of frames.] At lower-than-my-usual listening levels, a significant amount of my music played with no offensive issues...if I let go of my "awareness" of P-frame qualities.
   
• Details in complex orchestral passages improve vs. Plain (though still well behind P-frames or PF+HR). In the opening bars of Jerry Goldsmith's Star Trek Theme (Telarc SACD) a G1 piece, HR was able deliver midrange detail that Plain could only offer as scrambled eggs. With HR, that first orchestral strike, mainly brass & percussion, begins to show the instrumentsand even some texture from the tuba and the trombones. At lower-than-my-usual volumes HR was able to play this whole album tolerably well. I never got this from Plain in the past. HR did similarly fine with many other orchestral SACDs & CDs that I had not fully liked with Plain, many in G1. This includes the opening bars of Carmina Burana (O Fortuna), Runnicles, Telarc SACD a G1 passage, which become less congested with HR.  As a general rule, if I found a lower volume that could still accommodate the dynamic range of a recording against the room's noise floor , HR was better able to retain the details than Plain during complex passages.
   
• With HR, perceived dynamic slam was somewhat better than with Plain. This always remained a midrange improvement. Lower bass, which gained extension (later) never gained dynamic impact. To be sure, not even at their best are my MMGs, with (PF+HR), going to thump on your chest (most live music doesn't do that either) but PF and PF+HR do manage to shake you clothing and some fixtures on the walls.
   
• It did all of the above with a perceptible improvement in definition (solidity) of the imaging elements on stage, again, vs. Plain MMGs. This HR contribution also remained, primarily, a MID-RANGE feature all the time.
   
• HR does most of its good without removing all the warmth (coloration). It reminded me that "better sound" does not always mean more "accurate" playback. I prefer "accurate", but many people may want the warmer tone that stock MMGs can impart to voices and some instruments. HR cool's things just a little bit. Like I may have said to someone recently, the MDF frame is still "loose". So, it does its thing.
   
• There are some physical differences between my old MMGs and current ones. These may or may not reduce the relative amount of sonic improvement. However, I am confident that, at the very least, it will still be worth the effort if HR is tried in any UNFRAMED MMG. I believe so because the HR tweak brought valued improvements even to my P-Framed MMGs. With that said, let's go to FR+HR.
  
   

HR vs Plain

HR vs Plain

HR vs Plain

HR vs Plain

• A bargain improvement that may be one of the most significant tweaks you can make to MMGs. It is not earthshaking but it definitely is not subtle, particularly in the midrange and upper bass.  I am not advocating the ugly P-Frames (a temporary thing) but I am proposing that stand-braced MMGs could become better sounding. with HR. So, you are likely not to lose anything of what you like and gain much more than you get with some pricier tweaks. DO give this HR tweak 90+ hours of break-in if you think you lost bass extension at the very bottom of MMGs limited range.
   
• Complex orchestral passages do not necessarily play any louder, one just hears deeper into and gets more clear detail. Complex transients are similar in perceived strength, and to the limits of my gear, measure the same. An example is the opening bars of Jerry Goldsmith's Star Trek Theme (Telarc SACD) a G1 piece. At "a same" power setting, P-Frames alone peaked at 92db. So did PF+HR, after break-in.  (For reference HR alone, even after break-in, was 89db and Plain averaged 87+db) at the same settings. However, PF+HR was always the better one at resolving more detail during the initial brass/drum transients and full orchestral passages in between. This, in fact, was typical of all kinds of music that contain several layers of instrumentation.
   
• Imaging gained a little more solidity. Section & instrumental separation within the stage become more evident.
   
• You may often hear more things than you ever heard inside much of your music. If P-frames, with a little attention had revealed faint details, PF+HR told me "we are here!". As long as they are somewhere in the midrange area, more things are "willing" to be featured.
   
• The very top end remained just as good as with P-frames alone, from the start.
   
• The midrange becomes sweeter and deeper into an overall: enhanced, stronger and more solid stage. As treble-range instruments moved into the midrange area, I could hear increasingly more improvements in detail, clarity, tone and textures. Instrumental textures were either better or not diminished. In my case, reeds, and most specially saxophones, became better represented. The lower registers of flutes became richer. To a lesser extent, so did the lower range of violins. Trombones, in all types of recordings inched up a few notches in texture and sonority. Cellos were more likely to endear with their harmonics. Pianos, in general, supplied cleaner chords with improved tonal richness.
   
• Conversely, the upper end of most bass instruments also revealed more of their real personality, if captured in the recording. From the beginning, upper bass became better defined and textured. Bass simply tracked along with better midrange detail and texture. The impression that kept coming to mind was that of improved cohesiveness in the low-mid range. This, itself, did not change along the test period.
   
• As with instrument, vocalists, become more alluring. If a Plain MMGs can invest many voices with charming warmth (coloration), P-Frames can 'cool' them, even as it makes them more clear. The addition of HR to P-Frames appeared to have backfilled or bridged things so that voices gain better texture and more of their natural warmth. In one instance, I was forced to switch equipment to be absolutely sure that the improvement was really NOT more coloration. I was playing "Thank You" from Bernstein's "Mass" original cast (G2). The voice, the oboe and the clarinet ALL became simultaneously so more bewitching than ever! Later, after the tests, Renee Fleming's Bel Canto (SACD) was to better show off this newly-acquired refinement in a more modern recording, to my great delight.
   
• A "Deep" bass extension (relative to MMGs' typical range, people!) was the only element that WAS damaged initially by adding the HR tweak to the P-frames. This was at the very low (extreme end of MMGs reach) to which ONLY the P-frames could extend before this test. All G1 and G2 music with low frequency contents in that narrow area showed it. Suddenly, P-Frames lost the ability to show off without a subwoofer. SHOCK! The Eagle's "Hotel California", Paul Simon's "50 Ways To Leave Your Lover", Nestor Torres' Biscayne, David Sanborn's "Man From Mars" and worse yet "Tequila", not to mention the Patricia Barber "Companion" XRCD, all G2 selections, were the first ones to prove the loss. The G1 test selection promptly verified it. The few movies that I had been able to enjoy without a subwoofer with P-Frames, in preparation for the test, clinched it. It was lost. To be sure, I was perfectly willing to lose that bass extension in exchange for the other improvements...but, damn,  it still hurt!
   
• Thankfully, by around the 90th hour, the "lost bass" began to reappear. It recovered fully after around 110 hours or so. All manner of impressive (for no subwoofer or dynamic woofer) low bass is present again. The Patricia Barber "Companion" XRCD, as well as many other bass-rich recordings do not require a subwoofer to sound reasonably "complete". Certain movies do not even miss the subwoofer at all.
   
• Dynamic slam: At the midrange and upper basss it certainly notched up perceptively with PF+HR. In particular, pianos and percussion snap out more sharply when called to do so. At the extreme bass, (that which, by adding HR ,was lost and later recovered) it was as good as P-frames alone. Never really as impressive as typical dynamic drivers but, certainly, not feeble at all. Importantly, when playing along with the upper-bass, which was always was more dynamic, things do add up to quite better. And as you feel your clothing shake, that extra amount of detail in the midrange-bass may also reveal new things, if present in the music passage.
   

PF vs PF+HR

PF vs PF+HR

• I can't tell, just speculate. If you have fully-qualified frames, I suspect that this stage (Half-razoring) may not do as much for you. These frames already GRAB the inner Mylar frame . This is where the Cascade material is placed at this first stage of the Razoring tweak.
   
• Having said so, I'd still be the first to run and try it, if I were in your position. There's nothing much to lose if you try. Just remove it, if it doesn't pan out.
   
• It would not be surprising, however, that FULL-Razoring could do some magic with Framed MMGs in normal MylarFRONT configuration. OTH, I wonder about dispersion issues when Framed MMGs are also configured as Mylar-BACK (which seems to be common practice with Frames).