Loft 40


125-watt, 5-1/4" two-way bookshelf speakers

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Slim, two-way bookshelf speakers that are sure to delight your sense of sight and sound.

For those audiophiles who yearn for speakers with great looks as well as great sound, we’ve designed the JBL® Loft Series. These speakers are slim, elegant audio components that range from compact bookshelf to robust tower speakers. One remarkably versatile set in the line is the Loft40. It’s a pair of thin bookshelf speakers that offer listeners a great option for setting up a two-channel stereo or multichannel surround-sound system. Each speaker in the set features a 5-1/4-inch (133-millimeter) PolyBass woofer with FreeFlow port technology for big, clear and extended bass, and a 1-inch (25-millimeter) soft dome tweeter that can reach frequencies as high as 20kHz. Each speaker’s tweeter features our proprietary Elliptical Oblate Spheroidal™ (EOS) waveguide, which evenly distributes sound throughout your listening space and makes every seat the best seat in the house. The Loft40 speakers handle up to 125 watts and use a Straight-Line Signal Path™ (SSP) design to help ensure that a strong, precise signal arrives at each driver with little alteration from its original source. And the speakers are beautiful to see, too. All in all, the Loft40s’ breathtaking sound will impress you as much as their stunning looks.

Item# LOFT 40

General Specifications

Low Frequency Transducers Two 100mm (4") PolyPlas cones, magnetically shielded
High Frequency Transducer 25mm (1" ) soft dome on EOS waveguide, magnetically shielded
Power Handling 10 – 150 watts

Audio Specifications

Nominal Impedance 8 Ohm
Sensitivity (2.83V/1m) 90 dB
Frequency Response 55Hz-20kHz
Power Handling (Recommended) 10-125 watts
Sensitivity (2.83V/1m) 89dB

Speaker Specifications

High-Frequncy Transducer 25mm (1") soft dome on EOS waveguide
Low-Frequency Transducer 130mm (5-1/4") PolyPlas cone


Height (mm) 252
Width (in) 6-1/2
Weight (kg) 2.4
Weight (lb) 5.3
Height (in) 10
Depth (in) 7-1/2
Width (mm) 156
Depth (mm) 191

Control and Connection Specifications

Connector Type Binding post
Click here for a complete list of all specs for this product

Spec Sheet (EN)

494 KB
  • 2 JBL Loft40 5-1/4" (133mm) bookshelf speakers
  • Owner’s manual

Manuals & Downloads

The latest owner's manuals, quick start guides, and documents.

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Loft 40 is rated 4.7 out of 5 by 11.
Rated 5 out of 5 by from small but powerfull speakers Great Speakers, small size with a powerful sound. I have these speakers installed in my computer.
Date published: 2017-05-16
Rated 5 out of 5 by from Excellent Small Size Bookshelf Speakers I bought a set of Loft 40 Bookshelf Speakers to try because I liked the Loft 30 Bookshelf Speakers so much. They sound pretty closely matched sensitivity wise to the Loft 30's, but the Loft 40's have a little bit lower bass output. I use them on a Yamaha - R-S201, 100W.P.C. 2 Channel Stereo Receiver fed threw an old Optimus - 10 Band Stereo Equalizer & they can take some volume. I put about 85 watts to them at the most so far, after I broke them in for a good 20 hours ruffly at moderate volume & they played nice & clean without cone break-up or distortion with every type of music I threw at them. The tweeters on the Loft series speakers are what I like most about them. The tweeters never get to overly sharp or bright compared to the woofers & are crossed over at about 4200KHz compared to the Loft 30's that are crossed over low at about 1750KHz. These are excellent small bookshelf speakers & I am glad that I bought a set of the Loft 40 Bookshelf Speakers after buying a set of the Loft 30 Bookshelf Speakers. I recommend the Loft 40 Bookshelf Speaker to anyone, these little guys are so worth every penny! You can't go wrong with JBL speakers & the world class audio quality they have always provide us for all these years.
Date published: 2016-05-08
Rated 5 out of 5 by from High speaker review Purchased them four months ago. They performed better than expected, producing clear sound and adequate bass.
Date published: 2016-01-05
Rated 5 out of 5 by from Great price and service I have had the Loft 40 speakers for about 2 months now and have been very happy with them. I am using them as rear surround speakers for my 7.1 channel home entertainment system and they fill that position very well. I only wish I had ordered 1 more set at that price for surround side speakers. My speakers are now all JBL and I love them all!!
Date published: 2016-01-04
Rated 5 out of 5 by from Terrific sound, an in an amazingly small package. I purchased these speakers to fit on my bookshelves in my bedroom so I'd have some and be able to move the very large speakers I had in there to the den. Being familiar with JBL products over the decades I trusted that they would sound great, but I was surprised at how wonderful these little babies performed. They are clean, accurate, and reproduce music without much coloration and they create a realistic and rewarding sound stage. Better then I had hoped for. I'm considering a small sub to round out the low end but for now I'm quite pleased with how well these speakers are performing.
Date published: 2016-01-04
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Can you recommend a make and model of wall hanging brackets (swivel preferred) that will support the Loft 40's?

Asked by: GeorgioP
Unfortunately we cannot offer any one particular bracket, but typically speaking we always like the brackets that Omni-Mount make. Please check them out at www.omnimount.com. I'm sure they will have brackets that will work on the LOFT 40 speakers.
Answered by: Joe At Customer Service
Date published: 2017-12-02

what are the overall dimensions? HxWxD

Asked by: MW9397
Height: 10" Width: 6-1/2" Depth: 7-1/2"
Answered by: Joe At Customer Service
Date published: 2017-12-02

Can music be played in these speakers through and AUX port with my phone?

Asked by: Lsod
Unfortunately, the speakers do not have an AUX port, so you won't be able to use/connect it via an AUX cable to your mobile device.
Answered by: Amir at Customer Service
Date published: 2017-12-02

Hi, What is the impedance? Can I connect 6 ohm surround loudspeaker to a 8 ohm amp? What is the penalty? Tnx

Asked by: Rondor
The LOFT 40 speakers are 8 ohms. If your receiver can handle an 8 ohm load, most can, you will not have any issues using these speakers. As for 6 ohm speakers. If your receiver cannot handle a 6 ohm load, and you use 6 ohm speakers, it is possible to blow the amplifier. It is not recommended.
Answered by: Joe At Customer Service
Date published: 2017-12-02

what gauge speaker wire is best to connect these speakers?

Asked by: joebaby
Hello, Thank you for your inquiry. Here is the information you requested. Best Regards. Loudspeaker wire throughout the system should be good quality, loudspeaker grade audio cable with polarity coding. For loudspeaker wire that runs less than 25 feet, the cable should be a minimum of 18 AWG, for loudspeaker wire that runs up to 50 feet, the cable should be 16 AWG and for loudspeaker wire that runs longer than 50 feet, the cable should be at least 14 AWG.
Answered by: Zoltan
Date published: 2017-12-02

Have (2) 100 watt RMS Sony STR-DH130 Stereo Receiver Amp, have purchased 4 pairs of the Loft 40's to use and need to know recommended "break in" or "run in" please. Have Googled to research but would prefer info from THE mfg...Thank You. Bill Campbell

Asked by: gitarman58
There is no "burn in" period required for our speakers. You can run them right from the beginning, right out of the box, and you will not cause any damage at all. In the meantime, yes it is true that the sound will change ever so slightly as the speakers "burn in" during the first 10-20 hours of listening, but there is no harm in cranking them up right from the beginning.
Answered by: Joe At Customer Service
Date published: 2017-12-02
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