Look how crazy small, light and different JBL Boombox 4 drivers are compared to Boombox 3

Boombox 4 is starting to become available at more and more places for you to buy. I have already published 2 articles about the new Boombox 4 speaker. The first one was about the downgrades in Boombox 4 compared to Boombox 3. I wrote about the build quality and configuration downgrades. Then the second article was a detailed comparison of sound quality between the Boombox 4 and Boombox 3 speakers. After watching the teardown, I am kinda surprised by how small, light and different the new drivers' magnets are. Also, the construction, the build and design, the configuration and other aspects of the Boombox 4 are changed by quite a bit compared to old Boombox 3. Some changes are good and some other changes are cheap - this article is all about the internal surprises.

Some teardown videos are out on youtube, and you can check this teardown video by vua2hand that clearly shows the use of small neodymium magnets on the new Boombox 4 speaker. On another teardown of Boombox 3, we can see the use of very big ferrite magnets. There are many advantages and disadvantages of using neodymium magnets over ferrite magnets. The neodymium magnets can be much smaller because of much higher magnetic energy density. This allows light weight and compact motor design for the drivers. Also, similar amount of sensitivity can be achieved with less materials.

On the flip side, there are some disadvantages of using neodymium magnets. The big disadvantages are higher cost and thermal sensitivity. The neodymium magnets are already expensive and on top of that you need additional thermal management for good heat dissipation for high power audio systems. The old ferrite magnets look big, they are much cheaper and they can dissipate heat much easily. Also the construction doesn't need to be very precise with ferrite magnets, but precision is necessary for the motor movements using neodymium magnets - errors in gap geometry or coil design show up quickly.

This very important video by "Audio Bass Y" on youtube talks about the magnets' temperature. The new neodymium magnets on the Boombox 4 get kinda hot pretty quickly like under 10 minutes. This could make the strength of the magnets wear out in the long term if you use the speaker for hour-long sessions - from the source video. I think the magnets getting hot is not a good thing but plenty of portable speakers use the small neodymium magnets without proper heat management. And they seem to be working fine even after more than 4 years.

So, in terms of heat-management, the old ferrite magnets on the Boombox 3 do a much better job. The ferrite magnets are placed between a top and a bottom low-carbon soft steel plate. These plates help with the heat dissipation. So, the drivers on Boombox 3 using ferrite magnets get warm but not hot. However, the neodymium magnets on the new Boombox 4 get hot quickly. You would need quality heat-sink with the small neodymium magnets for good thermal managements. So the new drivers are way lighter but the heat management is a lot worse than the old drivers. Being a bit lighter is probably better for a Boombox if the heat doesn't cause damage later.

The Boombox 4 has 2 big woofers, 2 tweeters and 3 passive radiators vs Boombox 3's 1 big subwoofer, 2 woofers and 2 tweeters. Boombox 4 uses a 2-way system vs Boombox 3's 3-way system. The 3-way system on the old Boombox 3 is more complicated but can handle the load better than a 2-way system. Check out my article where I explained why the Boombox 4's 2-way system can be perceived as a downgrade. The new JBL Boombox 4 has 2 x 123 mm woofer and 2 x 20 mm tweeter along with 2 circular and 1 racetrack passive radiator. JBL Boombox 3 has 1 x 189 mm subwoofer, 2 x 81 mm woofer, 2 x 20 mm tweeter and 2 circular passive radiators.

This teardown shows that the rear racetrack passive radiator on Boombox 4 measures at 200 mm by 120 mm. The Boombox 4 has a RMS power rating of 210 watts on AC power and 200 watts on battery. Boombox 3 has a rating of 180 watts on AC and 136 watts on battery. So in terms of RMS, BB4's 210 vs BB3's 180 watts of power, which gives the Boombox 4 an additional 30 watts. We should expect a bit more deep bass and loudness from the Boombox 4 speaker. Check out my detailed sound quality comparison between these 2 speakers for more information.

The new hot-swappable battery feels like a proper upgrade even just by this super convenient replaceable design. If you want you can buy additional battery pack for the Boombox 4 and swap the discharged one with a charged one - keep the party going. The standalone battery pack for Boombox 4 is called the JBL Battery 600. For the battery, the new BB4 has a much higher capacity battery, which is excellent. So, Boombox 4 has a 99.02 Wh battery pack vs Boombox 3's 69.7 Wh battery. The flexible, more accessible and swappable new battery-compartment design is kind of a game-changer. Check out the battery section of Boombox 4 vs Boombox 3 article for more battery related comparisons.

Except the new battery design, other unit like the power supply unit is pretty similar looking on both the BB4 and BB3 speakers. The power supply units have their own housing with heat-sink for better thermal management. The construction of circuit boards including motherboard and all other sub or daughter boards show very high quality. Even though the new Boombox 4 has a plastic build, it feels high quality. However, the old Boombox 3 had metal handle and side panels. That metal construction on the Boombox 3 made it feel more premium than the latest Boombox 4 - kinda felt like a downgrade. The Boombox 4 looks a bit beefier but weighs quite a bit lighter at 5.8 kg vs Boombox 3's 6.7 kg - new magnets are very light.

Check out those articles from above, you can click on those linked images to read the articles. A while ago I published a review of the Samsung Galaxy A14 5G smartphone, check that out if you are into budget phones. In case you are interested in portable speakers, I compared 3 Boombox type speakers from 3 different brands such as Soundcore, Tribit and JBL. So don't forget to also check out that detailed comparison article about the JBL Boombox 3 vs Tribit Stormbox Blast vs Soundcore Boom 2 Plus.

So, the teardown shows that the LED light for each passive radiator has its own small daughter board just behind the passive radiators. The light show on the new Boombox 4 is very subtle but it will help increasing the fun at night. This article is focused on the teardown of both speakers and specially on the crazy differences of the drivers' construction. In my opinion, the difference is crazy and it is a huge jump to switch to neodymium magnets from ferrite magnets - comes with both advantages and disadvantages.

So, both speakers show high quality internal build and construction. The new hot-swappable battery design is a very good upgrade and a step towards the right direction. Main concern can be the new neodymium magnets on Boombox 4 getting hot under 10 minutes, but based on other portable speakers also running on similar magnets show no major issues long term, you probably don't need to worry about drivers wearing out. However, the new drivers are definitely crazy small, light and different. Also, the new Boombox 4 lost the metal construction of Boombox 3, which is a bummer.

Also, please check out the JBL Charge 6 vs Charge 5 story for highlights.
IF you're interested in mid-sized portable speakers, check my JBL Charge 6 vs Bose SoundLink Plus article. The JBL Charge 6 did better in the head-to-head comparison.