Holy Subwoofers Batman! A End-User Review of the Rythmik F18 - 18" Sealed Box Subwoofer

Discussion in 'End-User Equipment Reviews' started by Tom Lehman, Jan 2, 2019.

  1. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    My thanks to the AV NIRVANA Staff for starting this new forum to allow End-Users like myself to post our reviews and impressions of our systems and equipment choices!

    Happy New Year!

    Holy Subwoofers Batman!

    IMG_4116.jpg



    A End User review of the Rythmik© F18 - 18” Sealed Subwoofer

    MSRP
    $1850 ea Piano Black Finish
    $1630 each in Black Oak or Matte Black (vinyl)
    Multiple Sub Discount available at checkout

    Rythmik Audio – Austin, Texas

    http://www.rythmikaudio.com


    Rythmik©F18 Subwoofer
    Published Specifications ( More Available At http://www.rythmikaudio.com/F18.html)

    • Driver - DS1820 18" high excursion with custom sensing coil
      • Driver materials - One piece black anodized dish aluminum with rubber surround
      • Cast aluminum basket
      • Multiple aluminum flux de-modulation shorting rings
    • Amplifier
      • 900W RMS Hypex class-D patented servo controlled
    • Dimensions - 20-1/2"(W) x 20-1/2" (H )x 21"(D) - (23" D with grille and heatsink)
    • Shipping Weight - 133 lbs (115lbs net)
    • Frequency Response
      • 14 - 200 Hz (0db/-2db) with LFE inputs
      • 10 - 250Hz (+/-3db) with LFE inputs
      • 14 - 90 Hz (-2 dB @ 14 Hz) with LINE IN inputs
    • Crossover slope - Selectable 12 or 24 dB / octave (PEQ and XLR versions)
    • Crossover range (Low pass) - 25 - 100Hz
    • Rumble Filter (High pass ) - 20 Hz 18 dB / octave
    • Phase response - 90 degrees phase shift at 20 Hz (measuring mic has 18 degrees shift)
    • Phase adjustment - 0 - 180 degrees continuously variable
    • Bass damping factor settings - high (Q=0.5), med (Q=0.7), and low (Q=1.1)
    • Finishes - Available in black oak and black matte vinyl
    • Warranty - 5 years warranty on driver and 3 years on electronics
    • 45 day satisfaction guarantee



    I finally decided it was time to upgrade my aging and inadequate subwoofer(s). I had purchased a pair of Definitive Technology© PF15’s back in the day (1996) and they have served me well. Of course, I did purchase them with a pair of DTI BP2000s… one of the first speakers that sported a built-in 15” powered subwoofer. I used them as a center channel subwoofer and as a subwoofer for the surrounds using the BP2000’s for the front right/left subs. Yes, I know, I know… probably overkill (or just plain not needed) but I thought it was the bomb and I didn’t have to worry about phase matching the front speakers! Of course, maximizing placement with the subs built into the Bi-Polar main speakers was something you could do little about.

    About 6 years ago I sold the BP2000’s and most of the media room equipment, along with my last house but brought the PF15’s with me. I set up a new Media Room and purchased and installed B&G Radia 520i’s for the main right and left speakers, a B&G Radia 220i for the center channel speaker, and B&G SA320i’s for the surrounds. I have been using the DTI PF15’s as my system subwoofers ever since. Because I use them in conjunction with two Earthquake Sound© Q10B Tactile Transducers I always felt I had adequate low end impact for movies.

    However, lately I’ve been drifting more and more back to my first love…. Music! Along with that change in focus came a sort of discontent with the low end supplied by the PF15’s. I felt that they didn’t really have the low end extension or impact needed (or wanted) for music or movies anymore. My biggest concern was they lacked the speed, accuracy, and the tactile bass I was now looking for. I invested in a calibrated microphone and installed REW and took a few measurements. It didn’t take long to confirm that the PF15’s, that were certainly adequate in their day, had nothing below 30HZ and were kind of sloppy in their rendition of low and fast bass.

    So, armed with that knowledge, I started on the path to subwoofer enlightenment (research :-) even venturing out into the wild to listen to a few different subs at Magnolia and a couple of other spots around the Dallas area. Not finding anything that brought me to subwoofer nirvana I turned to the modern “book of enlightenment” on, well, everything… the internet!

    I started with top ten lists…. Useless! It is amazing just how many “Top Ten” and “best of” lists out there that have very little to do with science, testing, actual listening, or even common sense. These lists were so “all over the place” that they did not help at all. I got the distinct impression that many of these were "Paid to Place" lists.

    Looking back to past experiences I had heard JL Fathom ($3900ea) and Gotham ($16000ea) subs at CEDIA one year and was very impressed with the performance but left in shock by the price.

    A friend has two 15” Earthquake Sound SuperNova VI Subs ($2900ea) that I had a chance to listen to for an extended time. We had also listened to these subs at CEDIA as well (All the neighbors of the Earthquake booth had surely heard them as well :-). For sheer volume, impact and “shakeage” the Earthquakes were certainly worth considering since I could get a good deal on them. But I felt they were not as MUSICAL as I wanted. The search continued….

    I perused different forums and sites like AV NIRVANA, Audioholics, Audiogon, and several others, reading threads and reviews. From this cyber-stalking came several names that kept popping up as the biggest bang-for-the-buck options. Hmmm, I thought, I did have a budget after all….

    SVS, PSA, Hsu, and Rythmik kept repeating as the Internet darlings on the boards and searches. I started looking for reviews and found many to look over on all of the brands mentioned.

    The two I really started to focus in on were Hsu and Rythmik. The Hsu for the Price/Performance and the Rythmik for Performance/Musicality. The Hsu VTF-15H MK II came in a close second on my decision tree but I went with the Rythmik F18 (sealed cabinet) for a several reasons;

    1. Published Performance - The 18” sealed model, the F18, has a performance spec very close to Rythmik’s top single 15” ported subwoofer, the FV-15HP, in a manageable size box.
    2. Many positive reviews by both customers and professional reviewers.
    3. Value vs. Performance (YeeHah! Christmas Sale!)
    4. Musicality – This was a common thread within any discussion of the Rythmik brand
    5. Servo Control/High Power Flexible Amp (900 watts using Hypex Class D Amplifier Modules)
    6. Testing and results posted on https://data-bass.com/systems
    7. 45 day review and return policy
    8. Rythmik is located in Austin Texas… Close enough I could return the Subwoofers in the back of my SUV if needed.

    Now, don’t get me wrong…. I understand I was relying on other folks reviews and perceptions but when I go solely on other peoples reviews I tend to use the Olympic Scoring Method and throw out the highest score and the lowest score and use a composite of the rest. I also realize that sometimes, as in speaker selection, internet shopping is certainly not the way to do it. But in this case it seems Internet Direct shopping for a subwoofer was an accepted, good and valid way to go and I felt fairly comfortable with this approach.

    My decision was made after much gnashing of teeth and back and forth waffling and I placed my order on 12/20/2018 for Qty 2 – Rythmik F18 subs… and sat back to wait. Upon ordering I received an instant confirmation email from Rythmik and an order number for reference. And then… not much! Usually, I am used to all kinds of communication after a sale… estimated shipping time, stock issues… and so on but nothing showed up in my cyber mailbox on the day I ordered. I waited a bit and then sent two emails through different channels on the 22nd asking for status of the order just to encourage a little communication. I received an answer from Enrico at Rythmik the same day. He indicated that they were preparing the order for shipping and would be taking to the UPS distribution center on Sunday (the next day).

    I thought that was that but the next morning, Sunday, I received a call from Brian Ding (owner and designer at Rythmik) confirming the subwoofers would be shipped today.


    12/23/2018 Arrival Day!
    To my surprise and delight the subs arrived the same day Brian had called. I had a doorbell ring and when I answered Brian Ding was standing there! He and his wife Lynn were actually delivering my subwoofers! I had not quite understood when Brian had told me that morning he would be delivering the subs that day believing him to mean he would be delivering to the UPS terminal as earlier indicated by Enrico.

    He proceeded to unload his SUV and using a hand truck he had brought with him we rolled the subs up the sidewalk and stairs and boosted the subs into the foyer. My media room is on the second floor over my garage. I showed him the room and talked to him for a few minutes about the subs. We then went down and Brian volunteered to help me move the subs upstairs! Which we proceeded to do. He volunteered again to even help me unpack the subs which I declined knowing I was going to have to do some moving and tweaking. Normally I would have asked many questions and pumped the designer of the speaker for advice and information but I felt I had certainly occupied enough of their time. I introduced Brian and Lynn to my wife, we chatted for a while and then they were off to shop Dallas, returning to Austin that night. I was so grateful for his help! Brian and his wife are incredibly gracious and lovely people. What an incredible delivery experience!!


    The Packaging
    The packaged F18 weighs in at a whopping 133lbs with the subwoofer itself clocking in at 115lbs!

    Packaging at first glance certainly appeared adequate with the box proudly displaying what was inside.

    IMG_4092.jpg


    Opening the first box and folding back the flaps revealed a second equally heavy duty box. Instructions for unpacking were printed on the inside flaps of both inner and outer boxes.

    IMG_4094.jpg

    Opening the second box disclosed a closed cell foam cap with the accessory boxes inserted into individual niches. Pulling the cap off revealed more closed cell foam corner and side protectors.

    IMG_4095.jpg


    I then, following the instructions, removed all of the corner and side foam pieces then turning and reinserting one of the side protector/skids onto one of the two “solid” sides of the sub.

    IMG_4096.jpg


    Then, turning the package over on its side and using the side protector as a sled to slide the entire subwoofer out of the package. Couldn’t have been easier!

    IMG_4097.jpg


    Setup and First Impressions

    First impressions are important, or so my mother told me all those years ago. That was usually closely followed by “Cut your hair boy!”


    My first impression of the Rythmik F18’s were… WOW! The build quality looked good and the cabinets responded to the “Rap Test” with a good solid “thunk!” and no reverberations or ringing noted. The subwoofer is a sealed cube 20” on each side with the grilles removed. With the grilles off the 18” aluminum coned woofers looked REALLY NICE giving the subs a very serious, almost brutish, appearance.and while I knew I would have to cover them with the grilles to keep “you-know-who” happy I seriously considered displaying them sans grilles.

    They set on four medium sized rubber, screw in, feet. I normally set my subs on concrete platforms with large rubber isolation feet to decouple them from the carpeted floor. And, while they would sit on the 18” platforms my old subs previously sat on the overhang of the cabinet didn’t look very good so onto the carpet they went. When I get around to it I will search out some 20” x 20” pads or pour them myself.

    My room is somewhere around 3200 cubic feet and is 22.5’ by 18.5’ (9.5” high at the center) with 30 degree angled soffits on all four walls. The side and rear surrounds are mounted in this angled area.

    I started the setup of the subs by placing the F18’s in the same spots just vacated by the Diversified Tech PF15’s.

    PF15s at LP 12082018.jpg
    Reference - Diversified PF15s 12/08/2018

    That spot was to the inside (16”), of my two main right and left speakers and flanking my center channel speaker (16” either side). The subs were 12” from the front wall and about seven feet apart center-to-center. The size of my screen dictates a pretty big spread between my right and left with a noticeable toe-in for the speakers toward the prime listening position. This spot was determine by the “subwoofer crawl” method and just plain listening. I tried corner placement and it did boost the bass, but, with the PF15’s it exaggerated their natural “boominess” and limited range so I brought them more toward the center of the front wall to compensate.


    I have four small (1’x4’x4”) bass trap/diffuser/absorbers and four 2’x4’x2” absorber/diffusers in the room as a nod toward room tuning but they are really just there to smooth things out and tame the bass a bit. The walls have several niches for the equipment racks, media storage and the entrance door along one wall and three windows with cellular blinds along the other side wall add to the dispersion of the upper and mid frequencies.

    I started with a rough measurement with no Audyssey correction just to see what it looked like. It was ugly pointing out some major suckouts centering at around 40Hz, 84Hz and 115Hz.

    I then ran the Audyssey 32XT room correction application on the Marantz AV7703 using the Denon/Marantz iPad Audyssey App and the supplied Audyssey microphone to see what kind of curve it generated and ran REW again to see how Audyssey had compensated.

    I quickly determined that the old placement spots sucked with the new subs. I tried corner placement and, just as with the PF15s, just did not like the sound. Running Audyssey again did little to change my mind. I did some measurements and marked my spots and placed the F18s at the ¼ and ¾ spots along the front wall. This placement did work much better and smoothed the curve considerably. I did some movement in and out, and right and left to try and smooth the room modes a bit more. The subs settled into their new home spots and I settled into some serious tweaking.

    F18 Raw and Uncalibrated.jpg

    F18s raw and Uncalibrated


    Theater room drawing.jpg
    Room Layout




    The Fiddle Factor
    The amplifier supplied with the F18s allows for considerable fiddling. And, as I fiddled glancing over the two page instruction sheet I started the process to dial in the subs.


    HX1000XLR3 Amplifier.jpg
    The 900 Watt RMS – HX1000XLR3

    One thing to note is the supplied instructions may only be two pages but you should read them carefully…. Completely and carefully! There is a lot of information tucked into those two pages and you will save yourself a lot of grief, frustration and time if you read them carefully!


    Did I mention read carefully? I did a very typical “guy” sort of thing and just scanned the instructions (if that). As a result I wasted a good hour, or more, in useless pursuit of a good starting point when that setup/starting point is printed clearly on the instruction sheet. I have attached them below as PDF's if you have any interest.
    Setup is key with these subs and after my false start I reset and started with all amp controls/settings at Rythmik’s suggested starting point and ran another Audyssey calibration. Lo and Behold! This resulted in a much smoother curve and a much more listenable sound. I did some additional tweaking with the PEQ to iron out the smaller, but still present, dip at just above 40Hz (Room Mode). I got a curve I liked and started a Mini Break-In.


    F18 0-200HZ  Final 01022019.jpg
    Subs Final Curve - SPL

    F18 Final with phase 01022019.jpg
    Subs With Phase and SPL


    I ran multiple iterations of the REW sub sweep test (with my main speaker amps off). I then started a movie (Edge of Tomorrow) and let it play through twice to allow for a little “Break-In” of the subwoofers. I didn’t really expect much benefit from any break-in, and I realize this was not a truly meaningful length of time, but wanted to stress the subs a bit before any critical listening.

    After running my little “mini break-in” I settled in for a bit of critical listening and started with movies.

    The final resting place for the Amplifier settings were as pictured below. The only thing I experimented with, and that only with the music listening were the Damping selections changing between Medium and High.



    IMG_4114.jpg
    Final Configuration of Amplifier


    One last note… All testing was done WITHOUT the Q10B tactile transducers engaged. I actually listened to each scene, and most music selections, at three levels….

    1. Someone Else (wife) watching with me levels
    2. Action Movie Loud level…. and
    3. Stupid Loud Level

    Movies
    1. GI Joe, Rise of the Cobra (Blu-Ray) – This is one of my favorites gotos. When I want to show off my theater I always start with GI Joe! I started with Chapter 2 - the battle in the forest. This scene has plenty of low frequency action with the aerial battle and the ground fighting, most especially the multiple explosions and the 50 caliber action. The explosions were certainly tactile and the 50 cal (note: when it changes the gun operator perspective at about 8:25) was so percussive each round could be felt as a solid thud in the chest. My old subs really did not do justice to this scene without the Earthquake Q10B Tactile Transducers (everybody sit down please :-) engaged. With the F18’s the percussive effect was so intense I actually got up from my chair and double-checked just to make sure I had REALLY turned off the Q10B’s.


    2. Edge of Tomorrow (iTunes) – I started with a couple of scenes (among many in the movie) that had always impressed me with digging deep. The opening scene hints at what is come with some snippets of battle and lows drones interspersed among the newscasts. The extended looping battle sequence starting at Chapter Three is where it all kicks in and certainly has an extraordinary amount of low bass. The subs delivered, never flinching even at the highest volumes. I'm truly surprised the neighbors didn't call the police on me because of the insane volume I was pumping out. I'm afraid the police would have found me running about cackling, a bit hysterical, and quite uncaring, with remote glued in hand.

    3. The Dark Knight Rises (Blu-Ray) – I played the opening scene where Bane (Chapter 1) is taken aboard the plane in its entirety. This scene is not just bass but has significant high end energy bouncing about as well. The bass was incredibly deep and hard hitting and perfectly rendered by the F18’s. There was definitely also some infrasonic action happening as the subwoofers loaded the room. The result was a very unsettling feeling. At no time did the subs show any signs of stress or emit what I thought might be a strained or extraneous noise. In fact the low end sounded solid yet effortless at all levels.

    Left a bit short of breath and with a sore chest (well, possibly a
    minor exaggeration :-) I rested a bit before going to some music. I was very interested in how music would play out through the Rythmik’s Servo Controlled subs just to see if they lived up to the hype and word of mouth about their purported musicality.

    I have a fairly eclectic music collection that reflects my wildly disparate tastes so I have plenty of material to draw from so the choices were tough. My goal with music has never been to punish myself with excessive bass or fry my brain with scorching highs but to enjoy the overall experience. However, this is a review of subwoofers so I tried to choose some cuts and clips with known substantial bass content and what I considered great, well recorded sound and balance.

    As I have several sources to draw from I tried to use a little something from each pile.

    CD (OPPO UPD-203)

    Steely Dan (you knew that was coming, right?)– Two Against Nature
    Steely Dan has long been a goto band for demonstrating speakers. They have always had the highest quality recording production values. Add that to the fact the music is always so crisply and technically rendered in the studio you usually have a winning demo LP/CD/Whatever you can depend upon. Although I have pretty much every Steely Dan recording I chose the Grammy winning 2000 recording
    Two Against Nature for this review.

    I sampled every track on the CD and ended up listening to the CD from end to end while I was tweaking this review. Steely Dan has always been a studio creature for the most part with the one constant always being Walter Becker (RIP Mr. Becker) and Donald Fagen.

    Two Against Naturecontinued in this tradition using a variety of studio musicians. Despite five different drummers and two different bass players the sound remains remarkably solid and consistent. You need go no further for a textbook perfect drum/bass sound on virtually any Steely Dan recording (the exception being the debut album IMHO :-). Tightness and integration of the bass and kick drum has always been a hallmark of a Steely Dan recording and the Rythmik F18’s certainly displayed this in a much more convincing manner than my old subs.

    Thomas Dolby – The Aliens Ate My Buick
    On the 1988 The Aliens Ate My BuickThomas Dolby foray into funk the bass digs deep and provided the subs with a nice test. Some Love it… Some hate it (the album) but the bass supplied by the late, great Terry Jackson and synths by Mike Kapitan and Dolby himself provide a deep, articulate and well defined bass foundation. Good, snappy, well defined, funky bass is often a issue with some subs but the F18’s rocked it!


    SACD (OPPO UPD-203)

    Pink Floyd – Wish You Were Here - 5.1 Surround Special Limited Edition SACD

    Welcome to the Machine
    I queued up Welcome To the Machine and had a listen. The introduction with the odd machine noises panning about the room have some low end content, some of it quite low. The noises were crisp, percussive and well rendered with the low end drones solid and well-integrated with the system and surrounds. Low end impact, especially the synth lines, was visceral and impactful but blended well with the bass guitar. Roger Waters bass remained a separate instrument each note separate and distinct throughout the entire song while riding Richard Wright’s synth drones. During the outro the abrupt noise that sounds like a car door (and probably was) was a punch in the gut.

    Have a Cigar
    As I listened to Have a Cigar I was struck with Rodger Waters overlaying bass line being distinct and perfectly integrated with Nick Mason’s kick drum.


    Hiromi – Brain – 5.1 Surround SACD
    I like Hiromi Uehara… Better known as just Hiromi she is a popular “jazz” pianist/keyboardist. Hiromi is a frenetic powerhouse of energy and dynamics and plays piano and synthesizer with a technical skill and energy that few can match. Some of her works are solo piano but most feature small combos of wonderful seasoned players either in a acoustic or electrified format. Most of her releases are in the SACD format.

    The opening number of Brain, Kung-Fu Champion of the World, is a deep digging, full combo number featuring Piano and Synth with bass and drums accompanying. The subs rendered and played the complex interactions and dialog between piano , synth, electric bass and drums effortlessly.

    I sampled the rest of the tracks and was very satisfied with the F18’s speed and clarity.

    Another Mind – Hiromi - 5.1 Surround SACD
    I moved to another Hiromi SACD disk and was blown away by the title track, Another Mind. This track has a lot of energy on the piano’s lowest registers. This is the type of music that many speakers just give up on and that goes for subwoofers especially. The Rythmik F18’s reproduced this music easily and effortlessly with each crashing chord distinct and well defined bass. I was, in fact, startled by the depth of the tunes intro as I had never even heard, let alone felt, those deepest notes on my old subs. As an experiment I moved the disk downstairs to my office and played the disk on my Presonus Eris E5 near-field monitors. While the sound was pleasing, well defined and high energy the lowest registers of the piano were missing in action again, And, while I certainly heard the cords they just did not have the same impact as when played through the F18’s


    DVD/Blu-Ray Audio (OPPO UPD-203)
    Yes - Close to the Edge (1972) Remastered to DVD Audio

    Siberian Katru
    The word “Remastered” always sends a chill down my spine when seen. Many of the classics are probably better left untouched let alone remastered into 5.1 surround sound! However, I think a few definitely can and do benefit from a do over. Many of the older progressive classics lend themselves very well to updates, remastering and surround sound.

    This remastering of Close to the Edgegives gives you multiple versions of the classic Yes album in DVD Audio and includes the original master in stereo along with the remastered versions in stereo and 5.1 surround (both Dolby and DTS). The remastering and mixing to 5.1 was done by studio wizard Steven Wilson using the original master tapes.

    Chris Squire (RIP) has always been my idea of the bassist’s bassist. Treating the bass almost as a lead instrument he wove complex rhythms throughout Yes tunes and yet still provided the solid foundation when needed for the other members of Yes to build upon. This studio line-up of Yes was the dream-team of Anderson, Howe, Wakeman, Squire and Bruford.

    The subs rendered the complex bass with ease and left me very satisfied with the depth of the remastered material. The original master presented at the higher bit rate/depth afforded by the DVD audio format was a treat as well. The remastered stereo version of the album was very close to the original but with increased bass range and a little more energy on the top end. In 1972 when the album was recorded, the 18 minute
    Close To the Edge track time was pushing the boundaries of what LP technology and conventional recording wisdom of the day thought could be placed on an LP with maximum fidelity. The compromise was usually at the expense of some low end energy. The remastering from the original master tapes by Wilson restore some of that energy in the remastered versions in all formats.


    Apple TV 4K (Pandora)
    Primus - Les Claypool
    (Pandora Channel)
    Wow! Nothing compares to a full on bass assault by Les Claypool! If you doubt me give a listen. I happen to love both the talent and the humor put forth by Mr. Claypool in his various band incarnations. It is always a fun thing to listen to! Just add that to the fact that having a BASS PLAYER as the star player in a band is just unusual (and, a sort of perverse pleasure for some of us :-) and you are in for some UNIQUE MUSIC!


    Even with this slightly lesser quality source material the subs were great on this material. The powerful but always articulate bass of Les Claypool is truly the star here. The subs rendered his trademark sounds without missing a beat.

    Pandora published specs are a bit confusing;

    • Pandora on the Web plays 64k AAC+ for free listeners and 192kbps for Pandora Plus subscribers.
    • All in-home devices play 128kbps audio
    • mobile devices receive a variety of different rates depending on the capability of the device and the network they are on, but never more than 64k AAC+.
    I am a subscriber. and use the Marantz MDAT to try and moderate the effects of the compression going on so the Pandora quality is as good as it's going to be through my Apple TV 4K.


    NOTES
    I did try switching the Damping between High and Medium while listening and did not hear a significant difference. Medium might be a good compromise position for those that don’t want to take a stroll to the back of the subwoofer when switching from Music to Movies.


    While I listened to a lot of other tunes in several genres it is too much to burden you with. Once I got started I could not stop!


    Summary
    I had high hopes going in based on specs and reviews for the Rythmik F18’s and those hopes were well met by these powerful and deep digging subwoofers. At around $1600 ea they aren’t the least expensive ID subs out there, but they certainly aren't anywhere near priced out of anyone's reach. In my opinion, to my ears, and wallet, they are certainly amongst most versatile and accurate subs out there at even much higher prices. And, considering what I perceive as the high build quality, outstanding performance, musicality and appearance make them a bargain in my eyes.

    The theater performance is on a level that I have seldom experienced. Those two 18”woofers MOVE A LOT OF AIR when called for. I played the movies, and a lot of the music, at what is to be considered insanely high volumes. Not something even an aging rock-in’-roller like me would, or should, consider doing on a regular basis. Not once during these torture tests did I hear a complaint or a sign of strain from the subs.

    And,(notice the BIG AND”?) there is no doubt in my mind that the Rythmik F18’s excel as claimed at music reproduction. They are fast and dig deep when it is called for. With music some subs have a problem of either getting in the way or just fail to integrate well with the main speakers. Some are a bit sloppy, boomy, or emphasize certain notes/ranges over others. The F18’s are certainly not guilty of that at all. Adding to the music only when called on to do so and adding just what was needed they performed so well with music I was left wondering why didn’t I do this a long time ago!

    What makes these subs so pleasing, at least to me, is their direct and distinct appeal to different two camps… Music Lovers and Theater Lovers. The combination of insanely solid, crushing, punishing lows when called for, and tight, articulate, controlled bass make them winners in both camps and are a great choice for either! This is especially true for someone like me that enjoys both theater and music. Listening to these subs I am (re)falling in love with both my music and movie collections. I have earmarked a lot of both to replay in the coming weeks and months. What was old is now new again….



    F18 0-20K Final 01022019.jpg
    Final Room Curve - 2 – 20KHz SPL only


    Thank you for reading through to the end! And, thank you AV NIRVANA for allowing me the platform to present this review and my opinions. I hope that other end-users will utilize these pages and forum to post reviews and opinions of what is in their audio and video arsenals!

    Reviews, like both the professional reviews presented by AV NIRVANA staff (and others), and end-user reviews like this are, hopefully, done to give us all a fair chance at making a good decision with equipment that sometimes requires a significant investment, and that many of us will keep for years. And, to hopefully save us from the grief and frustration of a poor decision based on too little or biased information.

    I welcome your comments and suggestions so I can make improvements and make the next review better and more meaningful!


    Equipment used during this review;
    Pre/Processor and Amplification
    Marantz AV7703
    Parasound A21, A52+, ZoneMaster 450 Amplifiers


    Sources
    OPPO UDP-203
    Apple TV 4K
    Apple MacBook Pro (2013)


    Display
    JVC DLA-RS500

    Speakers
    BG Radia 520i (LR)
    BG Radia 220i (C)
    BG Radia SA320i (Side and Rear Surrounds)
    Polk CS-6 (ATMOS)


    Rythmik F18 Subwoofers (Reviewed)

    Measurements
    MiniDSP UMIK-1 calibrated microphone
    REW Running on a MacBook
    iPhone SPL Meter

    IMG_4117.jpg
     

    Attached Files:

    #1 Tom Lehman, Jan 2, 2019
    Last edited: Jan 10, 2019
  2. bkeeler10

    bkeeler10 Senior Member

    Joined:
    Apr 18, 2017
    Messages:
    289
    Likes Received:
    84
    Great writeup! Thanks for doing it. I just ordered a pair of these in black oak on New Year's Eve, just in time to catch the sale price. Can't wait to get them, though since I'm in Utah I suppose I'll have to wait on UPS rather than having them delivered by Mr Ding! They'll be going in my new theater of approximately 2200 cubic feet.

    Love that you're getting essentially flat response out to 10 Hz. And it's great to hear more confirming evidence that these are indeed fantastic subs.

    I thought about starting an Official Rythmik Subwoofers thread here on the forum. Perhaps I will do that once I get mine set up.
     
  3. Matthew J Poes

    Matthew J Poes Staff Writer
    Staff Member

    Joined:
    Oct 18, 2017
    Messages:
    1,801
    Likes Received:
    387
    Great writeup and thanks for getting our user reviews started.

    Rythmik is a real value in subwoofers. Those 18’s are very high performing for the money.

    You may find this article useful for subwoofer placement. I wrote it a year ago. Because of their massive depth, 18” subwoofers can exacerbate this problem.
    https://www.avnirvana.com/threads/sbir-matters-for-subs-too.2269/
     
  4. tesseract

    tesseract Senior Admin
    Staff Member

    Joined:
    Nov 12, 2016
    Messages:
    1,028
    Likes Received:
    239
    Location:
    Lincoln, NE
    Whoa, delivery by the owner speaks to great customer service, which Brian and Enrico have a long established reputation for.

    Thanks for kicking off our new End-User Equipment Review thread with a bang, Tom! Looks like you are about 10 dB down at 7 Hz, gotta love what one can do with sealed 18" subs.
     
  5. Sonnie

    Sonnie Senior Admin
    Staff Member

    Joined:
    Apr 2, 2017
    Messages:
    2,054
    Likes Received:
    437
    Location:
    Alabama
    Wow Tom... that is a LOT of excellent information there... love the measurements. Thank you!

    That Pink Floyd Wish You Were Here SACD is fantastic... I love cranking that up and chilling for a while. I think Wayne got a dose of it on one of his visits to my house and had it cranked on up too.

    Danny Richie use to sell the Rythmik kits IIRC... or maybe it was the driver. But it seems he did cabinets too because I remember something about them being super low resonance cabinets. I haven't heard from Danny in while... need to look him up.
     
  6. Wayne A. Pflughaupt

    Staff Member

    Joined:
    May 21, 2017
    Messages:
    236
    Likes Received:
    34
    Location:
    Corpus Christi, TX
    Fantastic review, Tom! And love that carpet in your HT room!

    Regards,
    Wayne
     
  7. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Thank you for the kind words! You are going to be so happy with the Rythmiks! The F18 is a monster. Starting a official Rythmik thread sounds like an excellent idea! Count me in on that!

    I’d be very interested in your impressions of the subs when you have a chance work with them a bit.

    The 10hz extension is a beautiful thing. It was fun to see the SPL build and the cones start moving before I could even hear it :-)

    Have fun with them!

    Cheers!

    Tom
     
  8. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Hi Matthew,

    Thank you! It took me a bit longer to put together than I thought. Original target was before the New Year but I kept tweaking the review:-) I agree that the Rythmik Subwoofers are a great value for the cost/performance equation.

    I hope mine is just the first of many user reviews that gets posted this year! Thank you and AV NIRVANA for hosting this access to the forum!

    Best Regards,

    Tom
     
  9. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Hi Dennis,

    I am certainly proud and happy to be the first to utilyze the new forum and hope that it is just the first of many this NewYear. I am hoping there are many folks out there that are ready to let their “inner reviewer” out!

    The low frequency extension surprised me even having looked at the specs. It was fun to witness the SPL start to build and the cones stat to seriously start moving even though I couldn’t actually hear anything :-) That 18’ speaker is moving a lot a air around!

    Thanks!

    Tom
     
  10. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Oh! I forgot to add Brian Ding personally delivering the subs was definitely a treat! He and his wife are wonderful people. Brian was gracious, helpful and very accessible! I think this is the start of a great relationship :-)

    Cheers!

    Tom
     
    tesseract likes this.
  11. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Thank you Sonny!

    And thank you and AV NIRVANA for the allowing me be the inaugural reviewer on the new forum. I am honored!

    I do love me some Pink Floyd and that disk is a great review tool and a fun listen!

    I hope I didn’t butcher the REW measurements too badly :-) its a great tool!

    Rythmik continues to sell the components to build great subs. For a semi-handyman like me though the finished product is a much safer, and probably less expensive, way to go! I do hope you have the opportunity to reconnect with your friend in this New Year!

    Best Regards and a Happy New Year to everyone at AV NIRVANA

    Tom
     
  12. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Thank you Wayne!

    It was so much fun to put together and I hope it is just the first of many by many different end-users!

    When I built my home the builder had nothing that I wanted so I had they put the cheapest carpet they had. When asked what color and style I told them the cheapest (didn’t care). Upon closing I immediately when to a late carpet center and purchased this. It was installed three days later... fun note, it glows under UV!

    Cheers!

    Tom
     
  13. bkeeler10

    bkeeler10 Senior Member

    Joined:
    Apr 18, 2017
    Messages:
    289
    Likes Received:
    84
    My plan all along was to build cabinets and buy the drivers and amps from Rythmik. When it came down to it, though, I realized I didn't have the time, patience or tools to do it. And when the sale came up on the F18, and I got to thinking about how much time I would spend and all the things I would need, I realized I would probably save only a few hundred bucks. Not pocket change, but not enough to put up with the delays and inevitable frustrations and unanticipated costs, only to have a less-than-perfect looking subwoofer.

    I do appreciate, though, that they give you the option to buy the parts and DIY your cabinets. What other sub manufacturer does that? None that I'm aware of.
     
  14. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    I think if I tried to make my own subs they would end up costing three times more than purchasing already made !-)

    As best I can tell they do not sell the servo/driver combo raw anymore.

    The servo is really adding to my enjoyment of the music as best as I can tell. Very happy with my choice.

    Let me know how you’d work out!

    Tom
     
  15. JStewart

    JStewart Active Member
    Supporter

    Joined:
    Dec 5, 2017
    Messages:
    237
    Likes Received:
    62
    Location:
    Central FL
    Late to the comments but still want to say THANK YOU. Awesome job on the review! Better than many professional ones (from other forums, of course :)).
     
  16. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Thank you for the kind words! That makes it well worth the effort!

    Best Regards,

    Tom
     
  17. Todd Anderson

    Todd Anderson News Editor / Reviewer/ Senior Admin
    Staff Member

    Joined:
    Jan 20, 2017
    Messages:
    4,830
    Likes Received:
    1,409
    Location:
    Balt/Wash Metro
    :T

    The in-room output on this beast looks super impressive. And it looks like it passed the Edge of No Tomorrow opening scene test with flying colors? That, alone, makes it a winner. :hsd:
     
  18. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Hi Todd,

    Truthfully, I have seldom been happier with a purchase equipment :-) The F-18s are certainly as advertised. Its kind of fun running a sweep on them from 0 - 200Hz and watching the cones start to go nuts and the pressure start to build in the room before you actually hear anything!

    The Edge of Tomorrow has some great content throughout and the F-18's show me exactly what I was missing with the older subs.... crushing effects and tactile bass!

    And, while they are superb on their own I'm experimenting with my old DTI PF15's in the back corners of the room. I have not by any stretch dialed them in or added any DSP magic to them but they seem to fill in the room nodes a bit and make the movie part of the experience palpable with better coverage throughout the room! I turn them off when listening to music but the basic notion of adding them into the mix seems valid. I will continue to work with idea and see where it goes :-)

    Tom
     
  19. bkeeler10

    bkeeler10 Senior Member

    Joined:
    Apr 18, 2017
    Messages:
    289
    Likes Received:
    84
    I've been thinking about trying this with my old pair of subs too. They roll off super fast starting at about 30 Hz. So if I try it, I figure I'll high-pass them at 40 Hz or so and let them help smooth out the response above there without becoming the weak link output-wise. It would be an interesting experiment. If I find the time to do it that is.
     
  20. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Bkeeler10,

    Sounds like a good plan! Let me know how it works for you. I haven't had a chance to tweak anything yet but initial results/sound is promising!

    Best Regards,

    Tom
     
  21. bkeeler10

    bkeeler10 Senior Member

    Joined:
    Apr 18, 2017
    Messages:
    289
    Likes Received:
    84
    Hey Tom, I finally broke out my old subs and had a go integrating them with the 2 F18 I have. Spent a lot of time fiddling with placement and (mostly) measuring and adjusting delays to get them in phase with each other. Used the miniDSP 2x4 to accomplish this.

    Of course, after the first go-around of fiddling which took about two hours, I was lying in bed that night and realized I had forgotten to turn off my prior Dirac calibration. So that was two hours wasted :rolleyesno:. So the next night I did it all over again. This morning I ran a fresh Dirac calibration, but have not had a chance to listen. Pre-Dirac frequency response is promising though. Perhaps I'll post measurements and detail my process over the weekend.

    Did you ever get yours integrated to your liking?
     
  22. Tom Lehman

    Tom Lehman Member
    Supporter
    Thread Starter

    Joined:
    Nov 6, 2018
    Messages:
    79
    Likes Received:
    59
    Location:
    Lewisville Texas
    Cool! Are you liking the Rythmiks? I

    I haven’t done much with the old subs yet. I just got them back into the mix before I bugged out to China. Been here three weeks and will return to US early April. Hope to grab some time to experiment a bit then. The only thing I noted is it does fill in a small suck-out that I have in the room at 40hz and sounds pretty good, even though it is only roughed in (really rough), with movies..... but not so much with music though!

    All I’ve done so far is to parallel them with my F18s. I have made no attempt to dial them in yet so I think you are way ahead of me in that respect. Are you running all four subs through the MiniDSP or just the old ones?

    Let me know if you get yours dialed in to a nice tight integration and how it sounds!
     

Share This Page