Polk Audio MagniFi MAX SR
Powered sound bar with Google Chromecast built-in audio, and wireless surround speakers
Polk Audio MagniFi MAX SR - Wireless surround speakers have keyhole slots for optional wall-mounting
Our take on the Polk Audio MagniFi MAX SR by Crutchfield's Emily S.
The wireless sub and surrounds make setup simple — they just need AC power.
Surround sound made easy
A common thread in our customer reviews for this Polk system is the ease of setup and use. In almost no time at all (and with minimal wires), you too can have true 5.1 home theater surround sound. With the MagniFi MAX SR you get a streamlined sound bar with a seven driver array, a powerful wireless sub, and two wireless surrounds for a truly immersive experience.
You also get 4K pass-through, plenty of connectivity options, and a few cables to boot (HDMI, optical digital, and stereo minijack to be precise). Even the wall-mount brackets are included, though you'll need to buy the appropriate fasteners for your wall type in order to use them.
Simple, yet powerful remote control
This unassuming remote is actually fairly full of cool features. You have independent bass control, surround sound volume and balance, and Polk's patented VoiceAdjust technology for crystal-clear dialogue. And if you'd rather not have to think too much about it, there are five sound-optimizing EQ presets: movie, sports, night, music, and all stereo.
The first three are fairly obvious to pick out, but you have to go deep into the manual to learn that the music note button actually toggles between the All Stereo and Music modes. This might resolve the issue some of our customers had with the sound quality of two-channel audio.
Roon-compatible for serious music lovers
The MagniFi MAX SR is also compatible with Roon, a subscription digital music player you download to your smartphone, tablet, or computer. It gives you multi-room audio playback for all your Chromecast-compatible devices and more. Roon accesses your digital music collection from your iTunes library or NAS drive. It also works with your TIDAL subscription. Roon lets you do deep dives into your music, showing artist bios, photos, reviews, and lyrics. Roon can also suggest other artists and songs based on your selections, making it easy to discover new music you'll enjoy.
- 5.1-channel sound bar system with wireless subwoofer and surround speakers
- allows pass-through of 4K content and HDR content
- works with Google Home voice controller
- gives you voice control over music features and volume
- slim design is ideal for placing below a TV on a stand
- wall-mountable (mounting brackets included)
- 180 watts of amplification
- seven built-in drivers:
- four 3"x1" full-range drivers
- two 3/4" tweeters
- one 1" midrange driver
- Dolby® Digital and DTS® decoding
- Polk's SDA® (Stereo Dimensional Array) surround technology offers a 5.1 home theater experience
- Polk VoiceAdjust™ technology helps keep dialogue intelligible, with adjustable center channel level
- 43"W x 2-1/8"H x 3-13/16"D
- weight: 6.05 lbs.
Wireless Music Options:
- dual-band 802.11ac Wi-Fi for smooth wireless music streaming
- Google Chromecast built-in for streaming music from the cloud with compatible mobile apps
- supported apps include Pandora, iHeartRadio, Google Play Music, TIDAL, and TuneIn radio
- Spotify Connect compatible
- built-in Bluetooth® for wireless music streaming from compatible smartphones, tablets, and computers
- aptX® encoding provides high-quality music streaming from compatible devices
- NFC-compatible for one-touch pairing with compatible smartphones
Wireless SR1 Rear Speakers (each):
- 30-watt (peak) built-in amplifier
- one built-in 3" driver
- connects wirelessly to sound bar
- threaded insert and keyhole hanger for optional wall-mounting
- AC power connection required (power cable included)
- 160-watt (continuous) built-in amplifier
- down-firing 8" woofer
- connects to bar wirelessly for flexible placement options
- AC power connection required (power cable included)
- subwoofer volume controls (via remote) to customize bass response
- 12-1/8"W x 14-9/16"H x 14-5/8"D
- weight: 13.5 lbs.
Connections and General Info:
- 3 HDMI inputs, 1 HDMI output (6-1/2' cable included)
- HDCP 2.2 compatible for connecting to 4K video sources
- HDMI connections support 3D/4K video, Audio Return Channel, and HDMI-CEC
- supported HDR formats: HDR10 and Dolby Vision
- optical digital audio input (6' cable included)
- 3.5mm analog minijack aux input (6' mini-to-mini cable included)
- Ethernet port for a fast, reliable wired network connection
- learns your TV remote's commands for single-remote use
- wall-mount brackets included (hardware not included)
- remote control
- warranty: 3 years (speakers); 1 year (amplifier)
- Our 60-day money-back guarantee
What's in the Box:
- Active soundbar speaker
- Wireless powered sub
- 2 Wireless surround speakers (SR1)
- AC power adapter (attached 58" DC cord)
- Two AC power adapters attached 9.75' DC cord)
- 58" AC power cord
- 69" AC power cord
- Remote control
- 2 "AAA" batteries
- 6.5' HDMI cable
- 6' Optical digital cable
- 6' Stereo minijack cable
- 2 Wall-mount brackets
- Wall-Mount Template (for soundbar)
- Wall-Mount Template (for surround speakers)
- Quick Start Guide
- Important Product Information
- Online Registration Card
Very happy with this affordable sound package
ken, Florence, NJ
Polk Audio MagniFi MAX SR Reviews
Average Customer Review(s):
Thanks for submitting your review
Features and Specs
|Pieces in System||4|
|Tweeter||0.75" Dome (2)|
|Woofer||1"x3" Oval-cone (4)|
|Surround Sound Decoding||5.1-channel|
|4K Video Compatible||Yes|
|HDR Video Compatible||HDR10, Dolby Vision|
|Audio Return Channel||Yes|
|Remote IR Passthrough||No|
|Works with TV Remote (IR)||Yes|
|Control by App||Google Home (iOS/Android)|
|Mounting Bracket Included||Yes|
|Surface Mount Stand Included||No|
|Speaker Parts Warranty||3 Years|
|Speaker Labor Warranty||3 Years|
|Amplifier Parts Warranty||1 Year|
|Amplifier Labor Warranty||1 Year|
|System Frequency Response||35-20k Hz|
|Sound Bar RMS Power||180|
|Subwoofer RMS Power||160|
|Inputs and Outputs|
|Mini Stereo Audio Inputs||1|
|RCA Stereo Audio Inputs||None|
|Optical Digital Audio Inputs||1|
|Coaxial Digital Audio Inputs||None|
|Sound Bar (inches)||2-1/8H x 43W x 3-13/16D|
|Sound Bar Weight||6.05 lbs|
|Subwoofer (inches)||14-9/16H x 12-1/8W x 14-5/8D|
|Subwoofer Weight||13.5 lbs|
Active Soundbar Speaker: The Polk MagniFi Max SR features a low-profile, slim-design soundbar speaker. The soundbar speaker is equipped with a seven speaker array which consists of two 0.75" tweeters, one 1" midrange driver, and four 1"x3" oval-cone full-range drivers, all powered by a 180W (RMS)/360W (Peak) built-in amplifier for dynamic sound. Twin side-firing ports aid in low frequency response.
Wireless Powered Sub: The included wireless powered subwoofer reproduces deep bass impact that you can feel from your movie and music soundtracks. It houses a down-firing 8" woofer, down-firing bass port, and built-in 160W (RMS)/320W (Peak) amplifier. You can independently adjust the wireless powered sub's bass level from the rest of the system's overall volume level.
Wireless Surround Speakers: The Polk MagniFi Max SR comes with two Polk SR1 wireless rear speakers to create a truly immersive, multi-dimensional 5.1 surround sound experience. Each wireless speaker features a 3" mid-woofer with built-in amplifier.
Proprietary Polk Technologies: Featuring Polk's patented SDA surround sound and Voice Adjust technologies, the MagniFi Max SR soundbar speaker system produces an immersive listening experience.
- SDA (Stereo Dimensional Array): Polk's patented Stereo Dimensional Array (SDA) surround technology creates an expansive multi-dimensional soundstage and detailed stereo image. SDA both heightens and widens the soundstage providing an immersive room-filling sound without sacrificing clarity. SDA also compliments Dolby & DTS encoded content creating an incredible cinematic experience.
- Voice Adjust: Voice Adjust technology dramatically increases vocal clarity and volume level for crystal clear dialog no matter what you're watching. You can customize the voice levels in the soundbar however you prefer to reproduce clear, crisp dialog and never miss a single word of your favorite movie, TV show, or sporting event.
Optimized EQ Presets: EQ settings for Movies, Music, All Stereo, Sports, and Night optimize the soundbar and subwoofer to ensure you get the clearest dialog, big surround sound, and deep bass for the best audio and home theater experience regardless of what you are watching or if you are watching late at night.
- Movie: Acoustically optimized for both movie and TV soundtracks. It also provides a bass boost, increased spatialization and enhances Voice Adjust levels for improved dialog clarity. It is the default sound mode for HDMI and Optical input sources.
- Music: Music mode gives you balanced sound and smoother bass while minimizing spatialization effects to ensure more natural sound reproduction.
- All Stereo: All Stereo mode provides room-filling sound by mirroring the front left and right channels to the surround left and right speakers.
- Sports: Enhances dialog-rich content, like sporting events, news casts, and talk shows.
- Night: Reduces bass and volume dynamics while improving voice intelligibility for low-volume listening.
Dolby Digital & DTS Compatible: The Polk MagniFi Max SR soundbar speaker system will decode Dolby Digital & DTS audio (up to 5.1ch) through its HDMI and Optical digital inputs. 2ch PCM audio is also supported through HDMI, Optical, and stereo minijack.
ARC (Audio Return Channel): This feature of the system's HDMI output allows audio to be sent from your ARC compatible TV to the MagniFi Max through the same HDMI cable already being used to send audio and video to your television. This eliminates the need for extra cables connected to your TV. The HDMI ARC output supports Dolby Digital 5.1ch & 2ch PCM.
Note: Because with many televisions, the ARC-enabled HDMI input will only pass 2ch PCM from devices connected to the TV via HDMI or analog, we recommend that you connect your Blu-ray player, satellite/cable box, and game system to the soundbar system's HDMI inputs directly; and then connect the soundbar's ARC-enabled HDMI output to your TV's ARC-enabled HDMI input. This setup will give you with the best overall sound performance.
Digital & Analog Audio Inputs: In addition to HDMI connectivity, the Polk MagniFi Max SR soundbar system provides a digital (optical) input and analog minijack (3.5mm) input for connectivity to your TV or other source components. You should make sure to turn your TV speakers off or set to "0."
- Optical Digital Input: The soundbar features a single optical (toslink) digital input to connect your flat-panel TV. The optical input can decode and reproduce Dolby Digital & DTS 5.1ch program material. The soundbar's digital input also supports 2-channel PCM.
- Stereo Minijack Input: The soundbar is equipped with an analog stereo minijack (3.5mm) input to connect your television (which may lack an optical digital output). If your TV is equipped with stereo RCA outputs, you will need a stereo minijack-to-RCA adapter cable (sold separately).
Note: The digital optical output terminals of many newer flat-panel TVs only send an audio signal in 5.1ch when receiving Dolby Digital/DTS surround sound from the TV's built-in tuner, network connection, or connected USB device; and will output only 2ch stereo from sources connected to the TV via HDMI, or RCA (like your Blu-ray/DVD player or satellite/cable box).
HDMI 2.0a: Featuring three HDMI inputs and one HDMI ARC output, the Polk MagniFi Max SR incorporates an advanced video section that features the latest HDMI 2.0a specification, including support for 4K Ultra HD video pass-through, High Dynamic Range (HDR) video, and HDCP 2.2 compatibility.
Note: There are no analog video inputs or outputs.
4K Pass-Through: The MagniFi Max SR supports up to 4K (3840x2160 pixels) video on all of its HDMI inputs and output. It will also pass a 480i, 480p, 720p, 1080i, or 1080p video signals via HDMI. There is no video resolution upscaling.
HDR (High Dynamic Range): HDR (High Dynamic Range) provides enhanced picture quality by simultaneously enabling greater detail for both the dark and bright parts of an image. HDR reproduces a greater dynamic range of luminosity or brightness levels, creating greater contrast. This increased contrast reveals the subtle nuances of the image, from detailed blacks and shadows to the brightest whites and colors, plus greater depth. The MagniFi Max SR supports two types of HDR formats - HDR10 and Dolby Vision.
- HDR10: HDR10 is an open standard and currently the most popular HDR format on the market. It supports 10-bit color and 1,000 nits. It uses static metadata at the start of a movie to tell the soundbar and your TV that the video content is encoded using HDR.
- Dolby Vision: Unlike HDR 10 which contains static metadata, Dolby Vision utilizes dynamic metadata which adjusts brightness, color, and contrast automatically for each scene. Dynamic metadata carries information that maps every image to your TV's display capabilities, so you see more of what the content creator intended. Dolby Vision supports 12-bit color and 10,000 nits.
Note: The system does not support the HLG (Hybrid-Log Gamma) HDR format.
HDCP 2.2 Compliant: All of the soundbar speaker system's HDMI jacks are HDCP 2.2 compatible which fully complies with the latest copyright protection standard for 4K video transmission.
Network Connection: The Polk MagniFi Max SR offers built-in dual-band (2.4/5GHz) WiFi (802.11 a/b/g/n/ac) and features a rear-panel Ethernet (RJ-45) jack for a wireless or wired connection to your home's network router. By connecting to your home's network, the MagniFi Max SR will support Chromecast Built-in, so you can wirelessly stream many of your favorite music apps from your Apple iOS or Android device, Mac computer, or Windows PC to the soundbar speaker system.
Chromecast Built-In: Chromecast built-in lets you cast many of your favorite music apps from your from your Android (OS 4.0+) or Apple iOS (8.0+) device, Mac computer, Windows PC, or Chromebook to the MagniFi Max SR soundbar speaker system. Chromecast built-in certified apps include Tidal, Spotify, Pandora, TuneIn, GooglePlay Music, YouTube Music, & iHeart Radio (click here for a complete list of compatible apps - subscription fees may apply). Chromecast built-in streams your music directly from the cloud instead of from your smartphone or tablet, so you don't lose any sound quality. Additional Chromecast built-in features include -
- Simple-to-Use: Chromecast built-in allows you to search, browse, play, skip, and turn up the volume directly from the music apps you know and love on your compatible phone, tablet or laptop. While you cast your music, you can still use your smartphone to answer a phone call, play a game, send a text, and even leave the room, all without interrupting what's playing on the receiver's speaker system or draining your battery. Friends and family can even use their own Chromecast Built-in compatible phone or tablet to cast music to your system by connecting to your home's WiFi network.
- Google Home: Multiple Chromecast built-in speakers can be added to the same WiFi network to form a multiroom audio system using the Google Home app. Using the Google Home app (for Apple iOS 9.1+ and Android OS 4.0.3+), you can sync multiple speakers with Chromecast built-in in multiple rooms of your home to play the same song throughout your house at the same time. Only Chromecast built-in compatible music apps are supported.
- Voice Control (Optional): Purchase the Google Home Wireless Speaker (sold separately) or other Google Home Assistant compatible speaker (see Accessories tab) and gain voice control of compatible Chromecast built-in music apps. You'll be able to access a specific music app and then select a specific station or song using only your voice. You'll also have voice control over Play, Pause, Skip, & Volume. The MagniFi Max SR & the Google Home Assistant device must be connected to the same wireless (WiFi) network.
Bluetooth Audio Streaming: The Polk MagniFi Max SR soundbar system supports Bluetooth A2DP which allows you to wirelessly stream audio from your Bluetooth-enabled smartphone, tablet, laptop, or desktop computer. You'll be able to stream stored music, music apps, podcasts, audiobooks, and other audio content from your Bluetooth source device to the soundbar speaker system. Basic playback control (such as Play/Pause, Previous/Next Track, & Volume Up/Down) can be done from the included IR remote. You will continue to use your Bluetooth source device for advance music navigation and to view song/artist information.
Note: The MagniFi Max SR does not support Bluetooth hands-free communication for phone calls.
Remote Control: The included IR remote control provides wireless operation of the Polk MagniFi Max SR soundbar speaker system. There are also several ways to use your TV, cable, or satellite remote to control the MagniFi Max SR system.
- HDMI CEC: If your TV is connected to the MagnFi Max via HDMI and your TV supports HDMI CEC, you can control the volume and mute functions of the soundbar speaker system from your TV's remote control.
- Polk Smart Remote Technology: Polk Smart Remote technology allows for most Samsung, LG, Vizio, and Sony TV remotes to control the MagniFi Max's volume and mute functions right out of the box (no programming required). TV must be manufactured within the last 5 years.
- IR Learning Function: If you have another brand of television that is not listed above, or you have a cable or satellite receiver, you can also program the MagniFi Max SR soundbar speaker system to respond to one of these remotes (remote functions include - Power, Volume, and Mute).
Top-Panel Controls: The following controls are found on top of the soundbar speaker - Power, Source, Volume, Mute, Voice Adjust, and Bluetooth Pairing.
Mounting Options: The Polk MagniFi Max SR offers flexible mounting options for the active soundbar speaker and wireless powered subwoofer.
- The soundbar speaker should be centered under or above your flat-panel TV screen. The soundbar can simply be placed on a tabletop, stand, or shelf (integrated rubber feet provide secure placement). The soundbar can also be mounted to the wall using the included wall-mount brackets (mounting screws not included). The unique wall-mounting system provides horizontal adjustment to ensure the soundbar remains level and centered under your TV.
- The powered subwoofer receives its signal from the soundbar wirelessly, so it can be placed virtually anywhere in the room (up to 30' from soundbar). Ideally, the powered sub should be placed along the same wall as the soundbar speaker. Placing the powered subwoofer in a corner will increase its bass response even more.
- The wireless surround speaker can be simply placed on a stand, shelf, or table-top. You can also wall-mount the wireless surround speakers using the built-in keyhole slots (mounting screws not included). In addition, each speaker includes a 1/4"-20 threaded insert for use with articulating wall-mount brackets (sold separately). Theses speakers are designed to be mounted horizontally (not vertically) and are marked "Left" & "Right". Left/Right balance controls allow for asymmetrical placement.
Power Requirements: The active soundbar speaker, wireless powered sub, and two wireless surround speakers will all require an AC power outlet. The soundbar speaker includes an AC power adapter with attached 58" DC cord and a detachable 58" AC power cord. The powered sub comes with a detachable 69" AC power cord. Each wireless surround speaker comes with an AC power adapter with attached 9.75' DC cord.
Our Product Research Team
At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.
Why did you buy this?
Best ratings on 5.1 system in my price range. [ MICHAEL Oct 17, 2018 ]
POLK.. Product and Reviews [ Gil Sep 29, 2018 ]
Good reviews, well known name and great price [ Fran Sep 27, 2018 ]
I have had great luck with Polk products in the past. This had all the features I was looking for and the price was better than the others I considered. [ David Sep 13, 2018 ]
All in one package Name recognition [ Duane Mar 25, 2018 ]
after a lot of comparison, it appears to offer the most complete feature set at an affordable price point [ Rocky Mar 22, 2018 ]
Polk quality [ Billy Mar 14, 2018 ]
Price and Polk reputation. Some not so positive reviews, but, that is to be expected. I know that Crutchfield has an excellent return policy, that with a $100.00 off makes it an easy decision. [ GC Mar 10, 2018 ]
Recommended by trusted audiophile who said for the money this was a great system. [ Daryn Jan 30, 2018 ]
good reviews [ Jay Jan 10, 2018 ]
Wanted wireless surrounds [ Dennis Jan 02, 2018 ]
7 questions already asked
Chris, there's a low volume "loudness" setting though it doesn't lower the volume for commercials. There is an adjustment for "voices" to enhance midrange and each speaker has volume and balance adjustments. [ Jay Aug 29, 2018 ]
I just unplug the speaker from the outlet for a few seconds then plug back in, let it reconnect. Works just fine after that. Have only noticed it doing that when I stream movies online [ Terrence Jul 24, 2018 ]
About a month into using it it would intermittently POP! very loudly. I simply reset them and repaired them and it has been great ever since! [ Dennis Jul 24, 2018 ]
Sometimes I have a popping sound and just turn off the system then turn it back on and normally it disappears [ michael Jul 24, 2018 ]
Yes [ Barbara Jul 23, 2018 ]
Nope haven't heard that yet [ Donald Jul 23, 2018 ]
No. It has slots that let it drop onto the included brackets. They are custom to this bar, as far as I can tell. The brackets would attach to the wall and the sound bar rests on them. [ ANDREW Apr 06, 2018 ]
I should wake up before answering questions. Yes it does have keyhole slots a both ends just like a traditional fluorescent light fixture. My apologies [ Duane Apr 06, 2018 ]
I misread your question, I was looking at the mounting bracket for the surround satellite speakers. I have not gotten to wall mounting, may never do that in preference to placement in front of my eventual 4K Ultra HDR 50" curved [ Duane Apr 06, 2018 ]
No. There is a drop down square slot about 1.5 X 4 inches. You supply the bracket to wall screws etc [ Duane Apr 06, 2018 ]
I have yet to get the Bluetooth function to work. Until Inget a smart TV I'm using my Roku to run Youtube and the cast to the Roku from my IPad. It's smashing then, I mean a YouTube has it all figured out [ Duane Apr 06, 2018 ]
I cannot respond to the question as I don't attempt to use the Chromecast feature. I do cast video from my PC to the LG television which then plays the audio through the Polk system. Sorry if that isn't much help. [ Louis J Apr 04, 2018 ]
Yes it has ARC and works great with my Hitachi Roku TV [ Dennis Jul 24, 2018 ]
I didn't want to drive my video through the Max so I only connect my Max to the TV with the TV's optical audio out and feed it to the Max. Hence, once configured on the TV, it plays any sound the TV gets from either the internet, or either HDMI source. I cannot respond to other configurations. [ Louis J Apr 04, 2018 ]
As long as you hook all your components through the TV and then hook the TV to the sound bar through hdmi arc then everything plays through the soundbar. [ JORDAN Apr 04, 2018 ]
You connect the soundbar to your TV through the HDMI(ARC) and then set the TV sound to external speakers. You can also stream music/audio from other devices to the sound bar by Bluetooth. Excellent sound in both cases! [ Jay Apr 03, 2018 ]
It works for hdmi and you can use the optical cord... both included! As for OTA... it does have a WiFi signal it gives off that you have to set up by downloading the google cast app... has Bluetooth as well... it does audio in and audio out! Such a beautiful device!!! [ Steven Apr 03, 2018 ]
have no idea. Only have smart tv and dvd hooked up. Dish is my service [ michael Apr 03, 2018 ]
You can have the bar plugged to your tv through hdmi arc Or optical and have all of your devices plugged to your tv (chromecast, roku, cable) and have your tv send the sound to the bar. This gives you the option of tv speakers or sound bar. Alternatively you can connect all of your devices to the bar and use it like a receiver to switch between devices. [ Donald Apr 03, 2018 ]
The soundbar accepts audio return from the TV via HDMI ARC. It works well with my Samsung TV, using the Netflix app on the TV for example. The soundbar can also take audio from the TV via RCA or Optical but HDMI ARC is the way to go. [ Patrick Apr 03, 2018 ]
It does have an optical input if your TV has one [ Terrence Apr 03, 2018 ]
As you adjust the volume on the Max (as opposed to from the TV) you can see reference lighting change from a single light to multiples as you go, but the steps are very small and you must be paying attention. (I am specifically referring to using the Polk remote not the television's. [ Louis J Apr 04, 2018 ]
There is a 10 LED array on the front of the bar. It indicates volume, bass, voice adjust, and surround speaker levels. It also is used to show left right balance of the rear surrounds if you are connecting via HDMI CEC, you should see volume level on your TV (this is function of your TV and HDMI CEC not the MAX). [ Michael Jan 15, 2018 ]
1 answer What forms of HDR does this soundbar support for passthru? The specifications are vague at best. I will assume it does HDR10. Does it support Dolby Vision and HLG passthru? I would think that if it had either it would be mentioned somewhere. If it doesn't, why would a product this recent not have it when Sony and LG have older soundbars with Dolby Vision added in an update? [ Matthew Jan 05, 2018 ]
It supports both HDR-10 and Dolby Vision. You will find this information, and more, by clicking the "Details" tab on the speaker's main webpage and scrolling down below the "Features & Specs" table. (It's also listed on the Features & Specs table) I hope that helps. My bio: https://www.crutchfield.com/bio/Ryan [ Ryan Jan 05, 2018 ] Staff
Frequently Compared With
Polk Audio MagniFi MAX SR
Powered sound bar with Google Chromecast built-in audio, and wireless surround speakers
Powered sound bar with 4K/HDR video passthrough and DTS Virtual:X®
JBL Bar 5.1
Powered home theater sound bar with wireless subwoofer and true wireless surround speakers