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JBL 306P MK II Review (Studio Monitor)

StuartC

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the varied feedback regarding the noisefloor of these speakers (and speaker family) is worrying for me as an Engineer. It suggests JBL doesn't have a handle on their manufacturing tolerance and quality control. I suspect they need to review the capabilities of the people in those roles.
 

Germanium

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the varied feedback regarding the noisefloor of these speakers (and speaker family) is worrying for me as an Engineer. It suggests JBL doesn't have a handle on their manufacturing tolerance and quality control. I suspect they need to review the capabilities of the people in those roles.
It may be that different people's ears have different sensitivity & that would be the cause of different feedbaback.
 

Robbo99999

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Probably also varies with how you set them up.
Not on my 308p Mkii anyway. You can have them so that they're just plugged into the AC without anything else attached and they still hiss at the same level, and even when you increase the volume knob on the back of the speaker the hiss doesn't increase, it just stays the same through all volume knob positions apart from zero which is a "mute button".
 

Tom C

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Not on my 308p Mkii anyway. You can have them so that they're just plugged into the AC without anything else attached and they still hiss at the same level, and even when you increase the volume knob on the back of the speaker the hiss doesn't increase, it just stays the same through all volume knob positions apart from zero which is a "mute button".
Does the -10dB/+4db switch make any difference?
 

Robbo99999

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StuartC

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Not on my 308p Mkii anyway. You can have them so that they're just plugged into the AC without anything else attached and they still hiss at the same level, and even when you increase the volume knob on the back of the speaker the hiss doesn't increase, it just stays the same through all volume knob positions apart from zero which is a "mute button".
What he said. I trialled a pair of 305s and this was my experience. At 1m listening distance it was too distracting, and even at 2m it was still noticeably audible.
 

Germanium

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On my sample the hiss does change with the volume level getting quieter as you get near minimum volume going away completely when turned all the way down. Power amp itself is very quiet. It is the input circuit generating most of the hiss.

I run my volume control 4 clicks from maximum. My sub generates too much noise if I try balance it with satellites at maximum volume plus this minimizes chance of overdrive sub amp. At very low frequencies below audible range some recordings I have do if set higher the amp can push out close to 400 watts (rated for 300 watts) at which point you can hear it clip. It only does this at subsonic frequencies as there is very little back electromove force generated at these frequencies to limit current drawn from amp.

This amp is full D.C. coupled due to my modifications & as such it will amplify D.C. signals with no loss of amplification factor. Care must be taken to limit any D.C. at input as such. With current volume settings it will likely not clip with any music I have including those with strong subsonic content.

I do have some recordings that have musical content down to 16 Hz (pipe organ) but I do also have one that goes below 10Hz (synthesizer). This is the one that can clip the amp if set any higher at all. This song is on Yanni's Truth Of Touch album. At this point it also comes very close to bottoming driver as well. As you can see from my picture of sub it is a monumental task to bottom it even at clipping below 10 Hz.
 
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Robbo99999

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What he said. I trialled a pair of 305s and this was my experience. At 1m listening distance it was too distracting, and even at 2m it was still noticeably audible.
I wouldn't have them on my desk at my PC due to the hiss, but they're absolutely fine for me in the living room as TV & music speakers as the hiss never intrudes or is noticeable in that particular use case, but no way could I have them sat idle at 1m distance next to my work/play PC.
 

Germanium

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What he said. I trialled a pair of 305s and this was my experience. At 1m listening distance it was too distracting, and even at 2m it was still noticeably audible.

My LSR 305's while not silent were perfectly usable on my desk near field. I do live in a somewhat noisy environment though. Same goes for all my LSR 3 series monitors that I have currently. I have total of 4 sets. 3 sets show in pictures plus 1 Red LSR 305 set not shown.
 
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StuartC

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I wouldn't have them on my desk at my PC due to the hiss, but they're absolutely fine for me in the living room as TV & music speakers as the hiss never intrudes or is noticeable in that particular use case, but no way could I have them sat idle at 1m distance next to my work/play PC.
For me it was the gap between songs where it became prominent and annoying, and even in domestic far field listening this particular pair were unacceptably noisy. Our maybe I'm just sensitive to it.
 

Robbo99999

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For me it was the gap between songs where it became prominent and annoying, and even in domestic far field listening this particular pair were unacceptably noisy. Our maybe I'm just sensitive to it.
You're probably very sensitive to it. I don't really see why the hiss level would vary significantly between units, I mean I think they're gonna be all the same in that regard.
 

StuartC

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You're probably very sensitive to it. I don't really see why the hiss level would vary significantly between units, I mean I think they're gonna be all the same in that regard.
Maybe, anyway I have Neumann Kh310s now, and you have to put your ear to the speaker come to hear anything. And even then it's basically nothing.
 

LightninBoy

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I just got a pair of these JBL LSR306P MK2 monitor speakers. These are definitely a cut above the LSR 305P(I have both). Significantly more transparent sounding. Great bass in stock form but I wanted something a little extra down there. Not in terms of bass level but I wanted more extension.

In order to accomplish the bass extension I have a Tannoy TS10 subwoofer ...
That is the exact combo I have ... JBL 306mk2 with Tannoy TS10. That little TS10 sub is a gem IMO.
 

Germanium

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That is the exact combo I have ... JBL 306mk2 with Tannoy TS10. That little TS10 sub is a gem IMO.
Cool.

Stock it sounds great but there was no output at 25 Hz & I wanted to be able to play back music that goes down to 16 Hz. I doubled the capacitance in the crossover to make like it had 25 Hz crossover & I bypassed the subsonic filter that cuts everything below 29 Hz. Then I D.C. coupled the power amp section to insure no loss of drive occurs at 16 Hz. Sub sounds just as good in the zone 30 Hz & above but now keeps going down & down with no loss of acoustical output at least down to 20 Hz.

One could probably do fine without D.C. coupling the power amp but to go lower than 29 Hz you need to bypass subsonic filter. There is a fair amount of music that has synthesizer bass lines that benefit from subs that have good output below 30 Hz.

Doubling the capacitance in this case does not actually lower crossover frequency. It just flattens the response below the resonant frequency of the subwoofer driver system. This resonance is between 45-50 Hz. Actual crossover still takes place around 70-80 Hz acoustically. Electrical output continues to climb until about 17 Hz at 12db/oct compensating for the acoustic roll off below resonance found in acoustic suspension bass drivers.

It still has all the positive character of the original TS10 sub. Absolutely great platform to modify amp & crossover. Only now I have every thing I want.

By the way I have been operating this subwoofer like this for many years. It is a very robust subwoofer system. Driver can handle a tremendous amount of bass. Far more than Tannoy allowed.
 
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Tom C

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My 306P are desktop at less than 1 meter, and I’ve never heard hiss. Don’t listen with my ear resting on the baffle, though.
 

Buckster

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P or PII ? My 305s I have to really concentrate from 30cm to hear my 308 IIs I can hear from 2.5m easily
 

LightninBoy

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It still has all the positive character of the original TS10 sub. Absolutely great platform to modify amp & crossover. Only now I have every thing I want.

By the way I have been operating this subwoofer like this for many years. It is a very robust subwoofer system. Driver can handle a tremendous amount of bass. Far more than Tannoy allowed.
That's interesting. I have no intentions of modding my TS10 sub, but good to know that it is that robust.
 

Fuzziekiwi

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I'm curious if there are any bookshelves with a similar sound to the LSR series. They're just a very fun speaker to enjoy music imo and have that open high end without being harsh for me. My main thing with ELACs are that the treble sounds dull unless you blast them, they have a pretty warm sound sig.

I've tried:
RP-600M (Returned- fantastic imaging/guitars but too bright overall)
KEF Q150 (Returned- fantastic imaging but sibilance)
Debut B6 (Kept)
Debut Reference (Kept)
Wharfedale Diamond 11.1 (Returned- nice mid range and bass didn't quite like the treble)
JBL Studio 530 (Returned- metallic sounding treble and downgrade from DBR)
 
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