JBL 308P MKII Studio Monitor Review

[amirm]

I’d say 2ft is a close but not unrealistic listening distance for computer speakers. Or measure at 1/2m (~20in) and then we extrapolate to the standard 1m. Or, just measure at 1m. You only need to be reflection free down to like 1500Hz.

Background noise will be pretty high I am afraid but I can experiment and see.

 

[richard12511]

Interesting. The waveguide is what I don't like about it, it's even worse when it looks like cheap shiny plastic like on this one. On the 5XX series they don't have grilles over the waveguide which is what I find most offputting. They look like bholes... I use some Arenas for surrounds and I think they have a similar design but luckily the grilles take care of that issue

Reading that "Most Beautiful Speakers" thread, it's obvious just how wide and varied people's aesthetic preferences are for speakers . Its so odd that the vast majority of people seem to prefer the same auditory characteristics(Toole like speakers), but the visual characteristics that people prefer are all over the place .

 

[DuncanTodd]

Reading that "Most Beautiful Speakers" thread, it's obvious just how wide and varied people's aesthetic preferences are for speakers . Its so odd that the vast majority of people seem to prefer the same auditory characteristics(Toole like speakers), but the visual characteristics that people prefer are all over the place .

Indeed. As I commented there, that thread could have been renamed to "The Ugliest speakers in the world" and many of the posts would still be relevant

 

[AnalogSteph]

I tested my JBL 305P MKII in a 43dB room, measured on my iPhone using C-weighting.
Only power cord was plugged in.
I put my ear against the tweeter, and reached around the back to toggle the input sensitivity back/forth.
Result? No change in hiss level.

What does decrease the hiss, as Amir also noted in this review, is when I turn down the volume control (the gain) on the back of the speaker down from 100%. This will decrease, but won't eliminate the hiss.

I think there are three sources of hiss on these that you might encounter - in descending order:

1. If you were foolish enough to use an unbalanced audio connection, the resulting ground loop is likely to invite plenty of power supply related noise (remember they are using a SMPS). So don't do that.
2. ADC noise. The ADC in these is a CS5341, rated 105 dB(A) of dynamic range if given the luxury of a +5 V analog supply. I would not count on a real-life implementation actually reaching this figure, it may fall a few dB short. What remains is just kinda-sorta enough to cover a few dB SPL up to max SPL @ 1 m (sensitivity spec is 92 dB SPL @ 1 m @ -10 dBV, i.e. 108 dB SPL @ 1 m @ 2 Vrms). The input gain knob presumably controls a digital gain setting, allowing you to reduce noise level if lower than maximum output is required. Not ideal but a tolerable tradeoff. Around 100 dB of dynamic range still is more than decent after all.
3. Amplifier and DAC noise from the STA350. This is the only one that you as a user can do absolutely nothing about. It still is just kinda meh but not "run for the hills" level.

You might also have source noise dominate ADC noise when using an unfavorable combination of output level (and dynamic range) and input sensitivity setting - I would not combine a Focusrite Scarlett Solo/2i2 3rd gen with -10 dBV, for example, switch to +4 dBu instead.

So in order to be happy with one of these, you want:

• a balanced output (or unbalanced properly converted to balanced)...
• ...capable of output approaching (<6 dB) either 2 Vrms (+8 dBu) or +20 dBu...
• ...with an output noise floor down more than 105 dB(A) from either of those levels.

That fortunately includes a lot and excludes only a little gear. The Rode AI-1 with its wimpy -6 dBu output would only get 305P MkIIs to 94 dB SPL @ 1 m at the best of times, so maybe not that one. Behringer UMCxxxHD or misc. modern-day mid-level onboard audio + a HD400 (around 0 dBu and 0...+3 dBu, respectively) would be in the yellow at least.

 

[richard12511]

1. If you were foolish enough to use an unbalanced audio connection, the resulting ground loop is likely to invite plenty of power supply related

All of my sources are consumer oriented, and none of them have XLR out, so I have to use an unbalanced connection . Consumer gear with XLR out tends to be very expensive.

 

[Robbo99999]

I think there are three sources of hiss on these that you might encounter - in descending order:

1. If you were foolish enough to use an unbalanced audio connection, the resulting ground loop is likely to invite plenty of power supply related noise (remember they are using a SMPS). So don't do that.
2. ADC noise. The ADC in these is a CS5341, rated 105 dB(A) of dynamic range if given the luxury of a +5 V analog supply. I would not count on a real-life implementation actually reaching this figure, it may fall a few dB short. What remains is just kinda-sorta enough to cover a few dB SPL up to max SPL @ 1 m (sensitivity spec is 92 dB SPL @ 1 m @ -10 dBV, i.e. 108 dB SPL @ 1 m @ 2 Vrms). The input gain knob presumably controls a digital gain setting, allowing you to reduce noise level if lower than maximum output is required. Not ideal but a tolerable tradeoff. Around 100 dB of dynamic range still is more than decent after all.
3. Amplifier and DAC noise from the STA350. This is the only one that you as a user can do absolutely nothing about. It still is just kinda meh but not "run for the hills" level.

You might also have source noise dominate ADC noise when using an unfavorable combination of output level (and dynamic range) and input sensitivity setting - I would not combine a Focusrite Scarlett Solo/2i2 3rd gen with -10 dBV, for example, switch to +4 dBu instead.

So in order to be happy with one of these, you want:

• a balanced output (or unbalanced properly converted to balanced)...
• ...capable of output approaching (<6 dB) either 2 Vrms (+8 dBu) or +20 dBu...
• ...with an output noise floor down more than 105 dB(A) from either of those levels.

That fortunately includes a lot and excludes only a little gear. The Rode AI-1 with its wimpy -6 dBu output would only get 305P MkIIs to 94 dB SPL @ 1 m at the best of times, so maybe not that one. Behringer UMCxxxHD or misc. modern-day mid-level onboard audio + a HD400 (around 0 dBu and 0...+3 dBu, respectively) would be in the yellow at least.

I'd just like to say I have these speakers with an unbalanced connection, and when connected to my TV they are only receiving 0.9V max from my miniDSP 2x4, and when they are connected to my laptop via Topping E30 DAC they are receiving max "2V minus 2dB for intersample overs", (whatever that ends up as, but quite close to 2V I think), and I was able to solve all ground loop issues which I initially had by running everything off one electrical outlet and using a simple ground loop isolator for my TV aerial which cost £2 lol. This setup works very well, so it's not strictly necessary to have a balanced connection to these speakers. The hiss (that is imperceptible at my listening distance of 2m) is present, but this is not related to whether the connection is balanced or unbalanced, and also the hiss on my speakers is the same at all volume knob positions on the back of the speaker....so it doesn't increase or decrease based on the volume level of the speaker amplifier (with the exception that if you turn the volume knob to zero then you get no hiss, but then you get no sound....so not relevant).

All of my sources are consumer oriented, and none of them have XLR out, so I have to use an unbalanced connection . Consumer gear with XLR out tends to be very expensive.

Don't be sad, it's not necessary to have balanced connections with these speakers, not if you solve ground loop issues.....but it does make it more hassle free in the setup using balanced connections because then you don't need to solve any ground loop problems, because balanced always solves ground loops by definition.....but no need to be sad............unbalanced = a good experience if you solve your ground loops!

 

[AnalogSteph]

All of my sources are consumer oriented, and none of them have XLR out, so I have to use an unbalanced connection . Consumer gear with XLR out tends to be very expensive.

Fortunately there is always the trusty Behringer HD400 if need be... you can get fancier line-level isolators, but this model should be plenty good enough for speaker use at consumer line level (I took some measurements several years ago and found nothing overly concerning, which is more than you can say about many of these things) and is more than reasonably priced. I've been using one to interface consumer soundcards to active monitors for years.

 

[arnold1013]

Wonder if there is a passive version. For me it looks like the performance may be compromised with the internal amps, ADC etc. $500 a pair can hardly bring you good amps

 

[Robbo99999]

Well, there is that gain control in the back so I don't have absolute levels. I set it to 0 dBu for the 96 dBSPL with the gain setting near what you see in the picture.

Your pic of the back of the speaker shows it's on the labelled -10dBv setting, which is the consumer max 2V setting. The other input switch sensitivity position is labelled as +4dBu which is the professional input level position for greater than 2V input and that's activated by flipping that little switch to the left position. Can't really read the font from the pic, but because I have this speaker I know what input sensitivity is selected in that pic because I can see the switch is flipped to the right which is the -10dBv setting for max 2V input.

Just wanted to make this clear in case there has been some confusion over what you've set or what people think you've set....I'm not sure what you've set for your actual tests (but do know what I can see in the photo I attached).... and thought I should mention this in case it impacts your test results at all, as I think it's relevant to your post I've quoted (unless I'm mistaken in what you're talking about).

 

[ernestcarl]

Cleaner, and the image illusion is better. Its clearly audible.

The Genelec monitors have better drivers with less distorsion, better amplifiers, and a better loudspeaker box.
The difference with music is bigger than Amirms test data shows.

Remember the high cost of the Genelec. I think both 8030C and 308 mkII is very good- for the money. And the price difference is justified.

It would be very easy to hear the difference by just listening to full band pink noise switching between these two speakers.

 

[jtwrace]

If you mean the heat maps, I’m not even sure how that would be possible without some custom coding, and even then it probably would look very messy (like asking to overly the Spins).

It can be done for all...we can overlay surface scan data.

 

[hollis]

I'd love to see a 308 mkii vs HT-12 comparison. When there is no sale, thats $500 off the shelf vs $500 DIY kit.

 

[LightninBoy]

I'm surprised how much different - and better - these measure than the 305s. Makes me even more interested to see the 306s measured (which Iis what I own).

 

[amirm]

I'm surprised how much different - and better - these measure than the 305s. Makes me even more interested to see the 306s measured (which Iis what I own).

You are in luck. A 306 fell on my lap today.

 

[LightninBoy]

@amirm Great review.

So if you shelved off the deep bass, peaked up the 1.7KHz dip and pulled back the 18KHz peak, they'd be pretty good except for the hiss at close range, distortion and running out of power/limiting?

As a powered monitor for musos making/mixing/recording music, are they really good enough with all those caveats? Even at USD$500pr?

I have the 306 MKIIs and use them for (amateur) making/mixing/recording music. The 306s also have the crossover dip and they hiss. I assume the 306s have a similar distortion profile.

Of these 3 issues, the only one that is impactful to my attempts at making/mixing/recording music is the crossover dip. I had to fix that with EQ.

The hiss I can barely hear at my recording position (about 3ft away from tweeters) when everything else in the room is off. Once the computer is on, its fans drown out the hiss. Once the music starts, the hiss is a complete non-factor. In a thread a while back, someone was excited about hearing low level details on their new speakers in an AC/DC recording. I could hear all those details crystal clear on these speakers.

As for distortion at high levels, for making/mixing/recording music you just need about 85db at the nearfield listening position, so the distortion is not a huge factor. For enjoyment, I love listening to music loud and my 306s definitely begin giving up before I like, but for making/mixing/recording music its not an issue.

So IMO, these issues are ideal trade-offs for the purpose of making/mixing/recording music for a low, low price. I do think these issues make the 308 MkIIs less appealing for the typical consumer uses though. For example, on desktop where they may be much closer to the listening position or as HT speakers where they need to play loudly at a larger distance.

 

[hollis]

Ok, so the measurements are great and the hiss, is just the hiss. But I tried these at my desk and, they did not work out.

I am not a "soundstage guy" but holy hell these sounded congested and "wrong" on my desk. The imaging was off no matter what I did. I even hammered out the frequency response with Dirac 1.0 back to flat (ish) and still sounded wrong.

I only wired them in since my LXmini rig is so complicated the 3-way crossover broke after a botched software update. I absolutely love the LXmini over this, but thats a $700 DIY kit (not including DSP and amplification).

I am back to loving the 308 in my dining room. They need space I think. Distance from the listener.

 

[amirm]

Ok, so the measurements are great and the hiss, is just the hiss. But I tried these at my desk and, they did not work out.

That's definitely too close for them. I had to pull my chair back to hear them well. Probably 5 feet or 1.5 meter.

 

[hollis]

That's definitely too close for them. I had to pull my chair back to hear them well. Probably 5 feet or 1.5 meter.

100% agreed

 

[LDKTA]

As expected. The 308s are so lovely.

 

[Chromatischism]

Help me to understand why I hear so much of this with many powered speakers? I can stick my ear completely into the waveguide of my 3600s and not hear a bit of hiss from my 25 yo Adcoms. Why can't they design these cheap plate amps to be quiet?

Discussion here seems to point to the ADC modules:

BTW check out those Kali measurements.