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Bose® Free Space® 51 environmental speakers

Item # 018FS51

The Free Space® 51 environmental speakers are yet another example of Bose®'s commitment to making great...

The Free Space® 51 environmental speakers are yet another example of Bose®'s commitment to making great...

Item # 018FS51

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C$499.99 pair

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About the Bose® Free Space® 51 environmental speakers

The Free Space® 51 environmental speakers are yet another example of Bose®'s commitment to making great sound possible just about anywhere . They're perfect for placement in a garden or backyard, so you can enjoy your favorite music outdoors. And you don't have to worry about placing the speakers in a protected spot — constructed of ultra-durable green plastic, these sturdy speakers are ready to handle the toughest weather and sound good doing it.

The Free Space® 51 environmental speakers are yet another example of Bose®'s commitment to making great sound possible just about anywhere. They're perfect for placement in a garden or backyard, so you can enjoy your favorite music outdoors. And you don't have to worry about placing the speakers in a protected spot — constructed of ultra-durable green plastic, these sturdy speakers are ready to handle the toughest weather and sound good doing it.

Bose's innovative radial design lets each speaker disperse sound in a 360º pattern, while protecting the weather-resistant driver — no worries about finding the perfect "sweet spot" for listening. Plus, these rugged, flexible speakers can withstand temperature extremes from 158º F to -40º F, and passed the rigorous salt fog test 66% longer than required by the Marine Industry Standard. That means they can handle direct exposure to the elements. They're designed for placement flexibility, too — they can be placed on or around decks or patios, secured in-ground, mounted onto hard surfaces, or just left free-standing. And with a 5-year warranty, expect years of expansive outdoor music.

Got wire?
Most speakers don't include any. Learn more about in-wall wiring at the Crutchfield Learning Center.
Shop our selection of in-wall speaker wire.

Read our hands-on review of the Bose® Free Space® 51 environmental speakers.


  • bass-reflex
  • downward-firing 4-1/2" environmental full-range driver
  • recommended power 10-100 watts with receivers rated from 4-8 ohms
  • base flanges with mounting holes for easy installation
  • three wire grooves in base permit stable footing and a tidy appearance
  • textured green enclosure
  • 14-1/2" base diameter; 14-7/8"H
  • withstands loads of up to 350 lbs.
  • warranty: 5 years
Priced per pair

What's in the box:

  • 2 Free Space 51 outdoor speakers
  • 4 Wire nuts
  • Owner's Guide
  • Bose Product Registration and Warranty Information
  • "Our Commitment to You" letter
  • Bose website information sheet
MFR #31763

Customer reviews

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Bose® Free Space® 51 environmental speakers reviews

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More details on the Bose® Free Space® 51 environmental speakers

Stacey B.

Product Research

Driver Technology
Enclosure Design
Mounting Options

Driver Technology

Downward-firing 4-1/2" Full-range Drivers: Each woofer cone combines a pulp and plastic mixture with waterproofing agents for high-quality sound reproduction that is resistant to the type of deterioration often caused by extreme conditions. Because the drivers are downward-firing, they are further protected from the elements to help deliver high fidelity, long-lasting sound. Each woofer uses a treated cloth surround.

Radial Design: The Free Space 51 speakers offer exceptionally broad, even coverage thanks to a radial design that enables 360-degree sound dispersion.

Enclosure Design

Environmentally Tested: While all Bose speakers are thoroughly tested, the extreme demands placed on outdoor speakers require an even more rigorous evaluation. Bose engineers re-create extreme environmental conditions, like exposure to sunlight, rain, heat, ice, even corrosive salt and fog. They also simulate years of exposure to these conditions to ensure that these speakers can deliver reliable, long-lasting performance.

Green Speaker Enclosures: The speaker enclosures blend in with backyard greenery.

Centrally Located Ports: The centrally located port on each enclosure enhances low-frequency performance to help preserve the depth and richness of your favorite music outdoors.

Domed Port Grilles: Positioned over the centered port, this grille reflects high-frequency tones into the listening area to help deliver clear, consistent performance.


Wire Grooves: Wire grooves on the bottom of each speaker enclosure prevent the speaker from rocking on the speaker wire and enables a professional-looking installation on decks, patios and other flat surfaces.

Mounting Options

Base Flanges with Mounting Holes: The mounting holes in each base flange provide easy, solid and secure installation on hard surfaces or in the ground.

In-ground Installation: Each speaker can be buried up to 7-1/4" in the ground. With the speakers buried, 7-5/8" of each enclosure will remain above ground.

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Customer Q&A

8 questions already asked

What type of speaker wire do these need ? Thank you
[ Bob  Feb 16, 2021 ]
1 answer
I used the underground speaker wire sold by crutchfield; in the ground (inside pvc) for 18 months so far, zero problems.
[ James  Feb 17, 2021 ]
How do these speakers handle getting occasionally wet? I want to place them near a pool.
[ Scott  Dec 04, 2020 ]
6 answers
Scott, I installed these right behind my pool. I live in the Houston, Tx area and we get plenty of rainfall. These speakers have gotten completely wet and work perfect. So occasional pool slash won't harm them. I recommend them.
[ Robert  Dec 04, 2020 ]
They're fine. In fact, I rinse mine off with a garden hose when they get extra dirty on top. I wouldn't spray water from underneath, but rinsing them and having them rained on has been no problem. These speakers are designed to be outside and in the elements. Best of all, they sound great!! I started with two. One on each side of my pool and then decided to order two more to even out the sound. Now we have a total of four around our pool which we found to be optimal. For placement--Each speaker is placed middle of each side and end, which we determined to be the best.
[ Andrew  Dec 04, 2020 ]
I have these speakers around my pool and they sound great, have not had any problems with them getting wet or damaged from cold weather, freezing temperatures and snow, will purchase several more this spring.
[ Danial  Dec 04, 2020 ]
Yes. I leave mine outside all year long.
[ MICHAEL  Dec 04, 2020 ]
I have two pair of these around a salt water pool directly on the ocean in Emerald Isle, NC! They get salt spray from both the ocean and the pool and have held up great. The first pair is 10-12 years old! Great bass and totally hidden in the shrubs. Go for it!
[ SCOTT  Dec 04, 2020 ]
I think they don't care. I have 4 of them sitting outside, uncovered, in the weather for years now, with no issues.
[ Chay  Dec 04, 2020 ]
Can these be painted?
[ adam  Nov 18, 2020 ]
1 answer
I don't see why not, just cover the small speaker grill piece in the middle open area. You may want to call or email Bose Support to confirm.
[ James  Nov 18, 2020 ]
What is the power source for these speakers? I'm looking for outdoor Bluetooth speakers that I can plug into an electrical outlet. I don't want battery powered speakers. Please advise.
[ John  Oct 17, 2019 ]
4 answers
Bought for my husband for pool lanai. He has them wired into stereo in garage 100 feet away. Wires inside plastic conduit. No batteries. Great speakers.
[ Kathy  Oct 17, 2019 ]
These are not powered speakers at all. Conventionally wire to the speaker outputs of any amp.
[ Thomas  Oct 17, 2019 ]
These are powered off of your supplied amplifier. You will need to run/bury speaker wire from your amplifier to each speaker. These are not powered bluetooth speakers and will not work for your proposed application.
[ Eric  Oct 17, 2019 ]
Hey John, I've got mine plugged into my stereo set up and I love them, they sound great, I may actually get another set
[ David  Oct 17, 2019 ]
Has anyone used these speakers in conjunction with an outdoor subwoofer? I'm thinking about using a Sonos Amp and the optional subwoofer out capability. Thanks in advance for any insight that you may have.
[ Bryan  Apr 15, 2018 ]
1 answer
I can't address your specific question regarding a subwoofer. However, if you have the speakers placed too far from the Sonos amp (Z120) you may need to consider a separate amp. I had the speakers placed ~100 ft away and it wasn't powerful enough. I blew one cheap amp and then upgraded to a better quality amp and it's worked fine.
[ John  May 02, 2018 ]
how do you get music to your speakers? Hardwire? Wireless? Bluetooth?
[ Gretchen  Apr 05, 2018 ]
4 answers
These units were a wired connection last time we installed .... don't know of any other options if not they would need power for wifi or blue tooth
[ bryan  Apr 10, 2018 ]
They are hardwired. I have a conduit thru an outside wall and buried in the ground.
[ Seth  Apr 05, 2018 ]
I hardwired them with heavy gauge outdoor speaker wire.
[ David  Apr 05, 2018 ]
Hard-wire . . . we have (4) and we love them!
[ Jasen  Apr 05, 2018 ]
What is your preferred volume level for these speakers? I powered four of them with Marantz Sr5008 receiver (100 watts/ch) and they are not loud enough until 65% volume. I barely hear them around 40% volume. The set up also includes a volume control and two Definitive Aw6500 speakers. I appreciate your input. Thanks and Happy Holidays.
[ Alper  Nov 30, 2014 ]
6 answers
My speakers are by a pool and also have a volume control and I have no issues with the volume level. What gauge wire and length are you using for these? I suspect you are getting a lot of loss in the cables. Are the other speakers on a separate channel of the receiver? As a test I would just connect the Bose speakers directly to your receiver with a short cable length and see if the volume level is what you are expecting. If it is, it would show you that you are losing power in your installation.
[ Richard Gonchar  Dec 07, 2014 ]
Hello Alper, I must first tell you that I am no expert with the technical side of stereo watts and speaker ohms. I have a set of 2 of these speakers and 4 rock loud speakers. The rock speakers, also purchased from Crutchfield, are weather proof loudspeakers and provide sound 24-30 feet from each speaker. The Bose Free Space 51 speakers, are not loudspeakers, and generally provide sound coverage 3-4 meters (up to 13 feet) from center of speaker placement. I can tell you that the technical folks at Crutchfield are highly knowledgable and helped me design my system. In answering your question, I usually play zone 2 (outside speakers) no louder than 50%. I don't remember the advisors name at Crutchfield, but ask them to compare your setup to Onkyo's TX-NR709 and Niles Rock Loudspeakers. I have a total of 18 (eighteen) speakers powered by my Onkyo (inside & outside combined) split in zone 1 and zone 2, with perfect sound quality. I love Crutchfield, and have been with them for more than 2 decades.
[ JEFF  Dec 01, 2014 ]
Hi Alper S. I have mine powered by the Sonos CONNECT:AMP and placed on opposite ends of my backyard, which is somewhat sizeable for San Diego standards (still about 40-50yds apart). When it is just a couple people lounging in the back, sonos volume at 50% is fine. When we entertain, it must go closer to 80% or greater (but still sounds fantastic). I hope this helps.
[ MATTHEW  Nov 30, 2014 ]
I'm not a big expert in this area, but are you powering all three sets of speakers with one receiver and one set of L/R outputs? I think you may be spreading the signal/power too thin. I have two sets of these too but each channel is going through a 12 channel amp at 100w per channel. I am having no issue when I run outdoor audio to four of these Bose plus two in ceiling patio speakers. Volume is appropriate across the entire volume spectrum. sorry, I don't know what else I can tell you. Best of luck.
[ BRIAN  Nov 30, 2014 ]
I fire a pair of Bose Free Space 51 speakers with a Yamaha RX-A730 receiver and find that they're not all that efficient at a lower volume setting either, especially compared to my Klipsch AWR650 "Rocks" directional speakers on my front patio. Granted, they're located about 130 feet away from my amp and I'm using direct burial 16/2 speaker cable, so I expected some loss in efficiency due to voltage drop over this distance. Like you, I find that it's at about 60%-70% volume where they begin to punch-out half way decent. I've kind of accepted that fact since I really needed omnidirectional speakers set into my backyard landscaping berms ... the Bose are awesome with their deep and discreetly dispersed sound, they're just not a booming, high-output party speaker like my Klipsch "Rocks". Hope this helps.
[ Jeff  Nov 30, 2014 ]
I have them hooked up to a separate amplifier. I don't really know what level. I do know that they sound amazing.
[ STEVEN  Nov 30, 2014 ]
Hi, I am planning to put Bose 51s around our pool. The pool is 16' by 40'. Do you think a pair of these would be enough or should I purchase 4? Please share your experience. Thank you.
[ Alper  Jul 17, 2014 ]
11 answers
My house in az has a cement brick privacy fence like all homes here. We have two around our pool and it is tear dropped shaped. About 14 by 40. Two speakers is enough for us but they are up against the wall I mentioned. That helps keep the sound in the area. That said we never turn it up past 40 percent volume. I think u will be just fine with two.
[ BRIAN  Jul 20, 2014 ]
I have a 16 X 36 pool and installed two of these in the garden area that runs along the far side of the pool (long side). They are spaced right about 30 feet apart from each other and about 12 feet away from the edge of the pool. They provide plenty of sound for the pool, and surrounding areas. I would consider 4 only if I were worried about achieving a more perfect stereophonic sound. Not a fault of the speakers, but the large distances they are separated and where you intend to sit relative to that placement. But hey, it's a pool area, right? Two will provide plenty for ambient sound and can easily annoy your neighbors if you want to crank them a bit.
[ MARK  Jul 19, 2014 ]
Two should be fine. I have a pool 20x40, and a 2000 sqft lawn next to it. I'm using 4 of them. Enjoy
[ ZHIGANG  Jul 19, 2014 ]
2 is plenty.
[ JOE M  Jul 19, 2014 ]
They are fantastic! I have high end outdoor speakers on my porch but the bose are just as good. I have 4 throughout my back yard allowing sound to be heard wherever I am. I have had the first pair since 2010 and I have nothing negative to say. I also get constant positive comments which have led to neighbors and friends installing them as well. You will enjoy them for years.
[ PAUL T  Jul 19, 2014 ]
If you are only installing the Bose speakers and no other surface mount speakers than yes get four (two pair), But if you are supplementing them with a surface mount then two (one pair) is more than enough.
[ TIM  Jul 19, 2014 ]
A pair is plenty. The sound is amazing.
[ STEVEN  Jul 19, 2014 ]
2 speakers will be plenty. Many of the upscale outdoor malls in my area use these very speakers. It was at these malls that I first became aware of the Bose 51s. I just completed a large hard landscape of my backyard patio and these speakers are nothing short of amazing. They sound professional at low and louder levels. Thru experimentation I found that 34 feet seems to be the optimum maxiimum distance to place them apart from one another. At that distance you never have a dead area of sound, it continues flawlessly from one speaker to the other.
[ MICHELLE R  Jul 19, 2014 ]
Hello Alper, I have a 20' x 40' pool and have 6 speakers total, 3 on each side of the pool (deep end, middle, and shallow end). Four of the six are rock speakers (also purchased from Crutchfield). All of the speakers combined provide outstanding surround sound, and by having extra speakers, you don't have to play music too loud in order to hear it from all areas of your yard. You may want to try 2 of the Bose 51s first, maybe placing them on each side of the pool and towards the middle. As far as the performance of the speaker, I am very pleased with my purchase and highly recommend the Bose 51s environmental speakers. The sound is incredible. I hope this helps. - Best regards, Jeff
[ JEFF  Jul 19, 2014 ]
The two we installed around our pool can be heard 400 feet away. Love them!!!
[ KURT J  Jul 19, 2014 ]
I forwarded your question to an Advisor and they responded with the following: I'm sure going with two of them would be ok, but if you are after more volume and overall output for a space of that size I would recommend going with 4. If you would like to discuss further you can contact an Advisor directly by phone (1-800-324-9695) or online chat.
[ Krissy  Jul 19, 2014 ]  Staff

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