JBL 308P MKII Studio Monitor Review

[respice finem]

This may open a can of worms (or judged as a really dumb idea) but has anyone hacked a pair of 308’s by bypassing the internal amps and driving these from a quality, external amp?

Based on Amir’s review, the weakness of their bass performance at volume and he felt that a bit of additional horsepower would really make these speakers sing.

Granted, I’m guessing this hack would require a crossover to be installed to but it seems like the 308s start with, “good bones” and the hiss and lack of punch at volume mignt be solved by this hack.

Considering their reasonable price point, it seems like this isn’t a huge risk.

I did a quick check over at diyaudio and a google search and didn’t find any 308 hacks to do this.

(I’d try this myself but it is a bit above my pay grade so I’m only throwing the idea out. I’ll now don my Nomex suit for the flamethrowers that may soon be coming my way!)

It will probably suffice for a rough distortion assessment, to feed the woofer - and I assume 90+ % of it will be from the woofer and the cabinet, as is usually the case. No solid state amp can "compete" with speakers in this dept. - except it's broken. I had the model and specs of the chip they use, maybe i can find it, but "on paper" specs were decent AFAIR.

It can end like some cases of car tuning - with having a broken, yet expensive piece of youknowwhat
If lower THD was so simple and cheap to achieve, JBL would have done it themselves.
Lack of punch at volume? Can't confirm, they get (subjectively) as loud as the Neumann do, just not equally clean.
Close to the wall, probably even louder (BR vs. closed box)

 

[LTig]

I guess I still have a copy somewhere / but how do I avoid getting the sweeps as soon as I press record?
Did my measurements semi-automatically with Carma so far and am not proficient in REW.

For a valid comparison, we would need a large sample, with measurements using the same gear and the same conditions, difficult...
And even then, in the end everyone's perception would be be a little different.

Open the RTA and klick on the record button. As long as the Generator is off there are no test signals played.

 

[respice finem]

OK, please don't shoot the piano man...

I got the speaker (one of course) measured, best I were able to. In reality it will be worse @1m distance, because in stereo both speakers are on.

Setup and remarks:

• Umik-1 calibrated (.cal file into REW), aimed at the acoustic center (area between the drivers), exactly 100 cm from the tweeter dome top
• SPL verified using external meter (Monacor SM-1, dbA only, alas)
• The room is about 50m2, two big carpets, but still on the live side acoustically. I'm using the 308 as TV speakers, so no "hifi-friendly" environment, the other factor is, vintage furniture would not really fit absorbers...
• thankfully the fridge stayed silent during recording

Results about as I expected, but everyone now can repeat the measurement and compare.

Screenshots: (first one background noise spectrum, second one with the speaker on, no signal fed)

The ZIP containing the .mdat file is attached.

 

[Blumlein 88]

You can zip the .mdat file and upload it as a .zip file.

 

[respice finem]

You can zip the .mdat file and upload it as a .zip file.

Thanks, It works indeed (see the updated post).

 

[Citizen]

This may open a can of worms (or judged as a really dumb idea) but has anyone hacked a pair of 308’s by bypassing the internal amps and driving these from a quality, external amp?

Based on Amir’s review, they show weakness with their bass performance at volume and he felt that a bit of additional horsepower would really make these speakers sing. Perhaps an external amp would also eliminate the hiss.

Granted, I’m guessing this hack would require a crossover to be installed to but it seems like the 308s start with, “good bones” and would make a good speaker great.

Considering their reasonable price point, it seems like this isn’t a huge risk.

I did a quick check over at diyaudio and a google search and didn’t find any 308 hacks to do this.

(I’d try this myself but it is a bit above my pay grade so I’m only throwing the idea out. I’ll now don my Nomex suit for the flamethrowers that may soon be coming my way!)

I have a pair of these with broken bass driver, they would be a great fit, they also don't hiss and even with just 25w to the tweeter they still play louder than the JBL's.

These can be got super cheap at the mo and they sound great.

Alesis M1 Active MkII

Alesis update their cost-effective nearfields.

www.soundonsound.com

 

[RayDunzl]

The noise btw is not just in treble, it's similar to white noise to my ears (yes I know, ears...)

I might simply record it with my UMIK-1 and post it here.

Hiss from the previous version of the LSR 308, which, as far as I know, has the same circuit board:

Newbie seeking to find some answers on studio monitor hiss levels

Hey everyone! Newbie here so if this belongs in a different section, please let me know. I've been reading the forums here for awhile, trying to find some info on hiss levels/self noise on several studio monitors. The only thing that was helpful was the graph showing the Brand vs Average self...

www.audiosciencereview.com

 

[respice finem]

Hiss from the previous version of the LSR 308, which, as far as I know, has the same circuit board:

Newbie seeking to find some answers on studio monitor hiss levels

Hey everyone! Newbie here so if this belongs in a different section, please let me know. I've been reading the forums here for awhile, trying to find some info on hiss levels/self noise on several studio monitors. The only thing that was helpful was the graph showing the Brand vs Average self...

www.audiosciencereview.com

My recording is @1m, so obviously different results.

 

[Yorkshire Mouth]

OK, please don't shoot the piano man...

I got the speaker (one of course) measured, best I were able to. In reality it will be worse @1m distance, because in stereo both speakers are on.

Setup and remarks:

• Umik-1 calibrated (.cal file into REW), aimed at the acoustic center (area between the drivers), exactly 100 cm from the tweeter dome top
• SPL verified using external meter (Monacor SM-1, dbA only, alas)
• The room is about 50m2, two big carpets, but still on the live side acoustically. I'm using the 308 as TV speakers, so no "hifi-friendly" environment, the other factor is, vintage furniture would not really fit absorbers...
• thankfully the fridge stayed silent during recording

Results about as I expected, but everyone now can repeat the measurement and compare.

Screenshots: (first one background noise spectrum, second one with the speaker on, no signal fed)

View attachment 311933

View attachment 311934

The ZIP containing the .mdat file is attached.

I’m reading on my phone - would you care to extrapolate on these results.

 

[respice finem]

I see what I see - which is a little "wideband" noise, mixed with ambient noise of course. Pretty much the same as what can be heard.
Sorry no spare time today for more. You can load the file into REW for more insight.

 

[MediumRare]

The whole LSR range just went on sale. The 308s are $100 off a pair. Not bad after 3 years of zero inflation, either!

JBL 308P MkII 8-inch Powered Studio Monitor

112W Powered 2-way Studio Reference Monitors with 8" Woofer, 1" Tweeter, and Magnetic Shielding (each)

www.sweetwater.com

 

[dinklesprocket]

Going to piggyback off this thread rather than make a new one: How good/bad are monitors for 2/2.1 home theatre listening?

I live in a condo apartment, so the living room isn't massive, nor can I play THAT loud.

I have a pair of Rokit RP8 G4s on order, but have been looking at the Adam T8Vs and JBL 308Ps as well. Distance from speakers to listening position is maybe 10ft.

Current speakers: KEF Q100s or JBL LSR305s, with a SVS PB-2000 (though it's usually off).

 

[Robbo99999]

Going to piggyback off this thread rather than make a new one: How good/bad are monitors for 2/2.1 home theatre listening?

I live in a condo apartment, so the living room isn't massive, nor can I play THAT loud.

I have a pair of Rokit RP8 G4s on order, but have been looking at the Adam T8Vs and JBL 308Ps as well. Distance from speakers to listening position is maybe 10ft.

Current speakers: KEF Q100s or JBL LSR305s, with a SVS PB-2000 (though it's usually off).

I use my two JBL 308p Mkii speakers for TV & Movie watching at either 1.5m or 3.8m depending on where I'm sitting for watching TV/movie and I think they're great for that purpose, and used for music listening in same positions. (I've got an SVS 1000 Pro sub combined with them). Flip the HF Trim Switch to -2dB to get the best balanced sound from them if you're not gonna be applying a full Anechoic parametric EQ.

 

[respice finem]

Going to piggyback off this thread rather than make a new one: How good/bad are monitors for 2/2.1 home theatre listening?

I live in a condo apartment, so the living room isn't massive, nor can I play THAT loud.

I have a pair of Rokit RP8 G4s on order, but have been looking at the Adam T8Vs and JBL 308Ps as well. Distance from speakers to listening position is maybe 10ft.

Current speakers: KEF Q100s or JBL LSR305s, with a SVS PB-2000 (though it's usually off).

Good question, tough choice. The Adam have less hiss, with a sub probably the T5V will do. But, cheap as I am, I would simply continue using the 305s, just giving the sub a bit more work to do (not just LFE but LFE+main). Effectively making it a 3-way system, with the added bonus of less distortion (the woofers don't have to play deeper bass any more).

 

[Trdat]

Is that high distortion due to the amplifier or the speaker itself?

 

[respice finem]

Is that high distortion due to the amplifier or the speaker itself?

The speakers - if their woofers have to do all bass and midrange, they will have higher distortion than when doing only the midrange (and only the higher parts of bass, because the lower part has "gone" to the sub). The lower the frequency, the more energy must be transduced = more air moved, at a given SPL.

 

[Yorkshire Mouth]

The whole LSR range just went on sale. The 308s are $100 off a pair. Not bad after 3 years of zero inflation, either!

JBL 308P MkII 8-inch Powered Studio Monitor

112W Powered 2-way Studio Reference Monitors with 8" Woofer, 1" Tweeter, and Magnetic Shielding (each)

www.sweetwater.com

I hope that follows in the UK.

I also wonder if this is getting rid of old stock because a new model is due.

Just a quick thought here. What makes a great speaker? Flat frequency response, low bass extension, low distortion.

Reading between the lines of Amir’s review, you’d think an extra $50 spent on slightly better amplification, and these would have it nailed.

 

[respice finem]

I hope that follows in the UK.

I also wonder if this is getting rid of old stock because a new model is due.

Just a quick thought here. What makes a great speaker? Flat frequency response, low bass extension, low distortion.

Reading between the lines of Amir’s review, you’d think an extra $50 spent on slightly better amplification, and these would have it nailed.

Especially if "better" would mean lower noise.

 

[Robbo99999]

I hope that follows in the UK.

I also wonder if this is getting rid of old stock because a new model is due.

Just a quick thought here. What makes a great speaker? Flat frequency response, low bass extension, low distortion.

Reading between the lines of Amir’s review, you’d think an extra $50 spent on slightly better amplification, and these would have it nailed.

All of those things make a great speaker. The JBL 308p Mkii gets a lot right. It doesn't have perfect frequency response, because you can improve it by flipping the HF Trim Switch to -2dB or alternatively using Anechoic Parametric EQ, but frequency response is still good even before that though. Directivity is very good. Bass extension is very good. Distortion is ok, but it's worse point. I can get them loud enough at 3.8 meter listening distance though without being disturbed by distortion, they do start to sound slightly unpleasant before overwhelmingly loud levels though, which I attribute to some kind of distortion. I'm pretty sure that if they were better speakers in terms of distortion I could listen to them louder, but to be honest I virtually never use them at even their most acceptable to me loudest level - so they're always in the green zone for me.

Did you buy these yet, you were almost going to?

 

[dinklesprocket]

I use my two JBL 308p Mkii speakers for TV & Movie watching at either 1.5m or 3.8m depending on where I'm sitting for watching TV/movie and I think they're great for that purpose, and used for music listening in same positions. (I've got an SVS 1000 Pro sub combined with them). Flip the HF Trim Switch to -2dB to get the best balanced sound from them if you're not gonna be applying a full Anechoic parametric EQ.

Good question, tough choice. The Adam have less hiss, with a sub probably the T5V will do. But, cheap as I am, I would simply continue using the 305s, just giving the sub a bit more work to do (not just LFE but LFE+main). Effectively making it a 3-way system, with the added bonus of less distortion (the woofers don't have to play deeper bass any more).

Thanks!

I think I'll give the KRKs a go, since I've already bought them. I do like my LSR305s (despite them not being necessarily the flattest), so I'd imagine the 308Ps would be pretty nice (given they're both JBL and probably similar).