Hello, I'm welcoming you with a new teardown: JBL Control 28-1 passive speakers meant to be used indoor and outdoor. Given that it's an outdoor speaker too, I do not expect it to sound as good as an indoor speaker, given rougher and water-proof drivers membranes, anti UV exterior plastic etc. Specs can be read here: Control 28-1 Spec Sheet.
- Components:
• 8” woofer with woven fiberglass cone
• 1” PEI diaphragm tweeter with fluid cooling - Contemporary, high-design appearance
- Built-in InvisiBall® mounting hardware*, plus available U-bracket
- Weather resistant enclosure and transducers
- Wide 100° x 100° coverage
- 120 Watt power handling (240 Watt program) in direct 8Ω setting, plus built-in 60 Watt 70V/100V multi-tap transformer.
- High fidelity sound character with broad frequency response of 45 Hz – 20 kHz.
The previous version of JBL Control 28 has been teared down here and I really enjoyed the short movie presentation. The author disassembles almost every single part of these nice speakers.
Speakers are rated IP55 if the front MTC-28WMG-1-WH WEATHERMAX GRILLE and the back MTC-PC2 or MTC-PC3 panel cover are properly installed. I'll copy-paste here from its datasheet: "Exceeds MilSpec 810 for humidity, salt-spray, temperature & UV. Passes MilStd-202F for salt spray and ASTM G85 for acid-air plus salt spray. Optional MTC- 28WMG-1 WeatherMaxTM grille for breaking up driving rain and for especially difficult environments".
Speakers are rated IP55 if the front MTC-28WMG-1-WH WEATHERMAX GRILLE and the back MTC-PC2 or MTC-PC3 panel cover are properly installed. I'll copy-paste here from its datasheet: "Exceeds MilSpec 810 for humidity, salt-spray, temperature & UV. Passes MilStd-202F for salt spray and ASTM G85 for acid-air plus salt spray. Optional MTC- 28WMG-1 WeatherMaxTM grille for breaking up driving rain and for especially difficult environments".
Front picture with the grill On
Front picture with the grill Off
Backside line/power level selector
Backside wires connectors
Inside picture with both drivers
8" Woofer - front close up
8" Woofer - UTC1733
DC resistance of the woofer
1" Tweeter - front close up
1" Tweeter - UTC1739
DC resistance of the tweeter
8" Woofer - UTC1733
DC resistance of the woofer
1" Tweeter - front close up
1" Tweeter - UTC1739
DC resistance of the tweeter
I see in the specs the term "fluid cooling" for the tweeter and I have no idea where the fluid cooling (perhaps ferrofluid?) is located, given that the tweeter has a big visible regular magnet attached on the backside. I suppose the tweeter is covered in ferrofluid and on top of that a big magnet surrounds it.
The inside stuffing
The line voltage transformer and the selector on top
Top of the crossover filter
Bottom of the crossover filter
I do hope that the above images are self-explanatory for most and based on these and on the specs provided by the manufacturer we can see a great nice looking piece of indoor/outdoor speakers. I personally use them as rear speakers in my home setup and the sound is very clear, a bit on the bright side perhaps, with female voice accents, somehow contrasting with my front speakers CANTON GLE 496 that are having a more neutral sound (perhaps a bit on the dark side). Given the increased level of clarity, the JLB Control 28-1 could be used as monitor speakers for home or studio use, especially if paired with a subwoofer. These speakers are rough and built to last, so using them outside might not be an issue as well, especially if the backside connectors are properly sealed, as per specifications and JBL recommendations.
However, some other things I've noticed as well, that I can not fully understand. First one is related to the wire thickness inside, same issue seen in the Mackie MR10SMK3 subwoofer: the wires are simply too thin.
Aluminum wire coming from the 8" woofer
22 AWG aluminum powers the 8" woofer
18 AWG aluminum wires the line voltage/power selector
Wires "upgraded" and bypass
I wanted to get rid of those thin wires and install 0.75mm2 copper ones, but I've also got rid of the line voltage/power selector as well by bypassing it with a couple of wires, although this is usually not necessary on this model because the selector itself has a THRU setting that already does that.
I also found that the passing inside is somehow lacking in depth and volume, at least comparing with the previous model from the Youtube movie review from the beginning of this article, so I've added a bit more of "stuffing" inside.
A bit more stuffing added inside to get rid of any possible inner standing waves
In the end I've compared a couple of rough in-home measurements pre vs. post the above so called "modding" (rewire and stuffing).
ECM999 + Motu M4 + REW
SPL and THD for the original speaker
RT60 Decay for the original speaker
Spectogram for the original speaker
SPL and THD for the modded speaker
RT60 Decay for the original speaker
Spectogram for the modded speaker
As we all can see, the so called "modding" by rewiring and a bit of stuffing added is not making any real difference, at least I can't measure any, but still those thin wires should be upgraded by JBL in their future Control 28 revision of these speakers.
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