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JBL 305P MkII Review (Erin)

hardisj

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Review copy/pasted from my site:
https://www.erinsaudiocorner.com/loudspeakers/jbl_305pmk2/


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JBL 305P MkII - Powered Two-Way Studio Monitor Review
  • Saturday, May 1, 2021
DSC01842.JPG

Foreword / YouTube Video Review
The review on this website is a brief overview and summary of the objective performance of this speaker. It is not intended to be a deep dive. Moreso, this is information for those who prefer “just the facts” and prefer to have the data without the filler.

However, for those who want more - a detailed explanation of the objective performance, and my subjective evaluation (what I heard, what I liked, etc.) - please watch the below video where I go more in-depth.



Information and Photos

The JBL 305P MkII is a powered 2-way Studio Monitor featuring a 5-inch midwoofer and 1-inch dome tweeter. It features Balanced XLR & 1/4” TRS Inputs with input sensitivity options of +4dBu/-10dBv, a boundary EQ (Low-Frequency shelf) as well as a High-Frequency shelf to tailor the sound. The following is from the manufacturer’s website:
The next-generation JBL 305P MkII powered studio monitor makes legendary JBL performance available to every studio. With the revolutionary JBL Image Control Waveguide and refined transducers, JBL 305P MkII offers stunning detail, precise imaging, a wide sweet spot and impressive dynamic range that enhances the critical listening capabilities of any modern workspace. Featuring patented technologies derived from the JBL 7 Series and M2 Master Reference Monitors and, sporting a sleek, modern design, JBL 305P MkII delivers outstanding performance and an enjoyable mix experience at an accessible price.


MSRP is about $300 USD for a pair.

And here are some specs copied from the manual:

specs.png


DSC01843.JPG







CTA-2034 (SPINORAMA) and Accompanying Data
All data collected using Klippel’s Near-Field Scanner. The Near-Field-Scanner 3D (NFS) offers a fully automated acoustic measurement of direct sound radiated from the source under test. The radiated sound is determined in any desired distance and angle in the 3D space outside the scanning surface. Directivity, sound power, SPL response and many more key figures are obtained for any kind of loudspeaker and audio system in near field applications (e.g. studio monitors, mobile devices) as well as far field applications (e.g. professional audio systems). Utilizing a minimum of measurement points, a comprehensive data set is generated containing the loudspeaker’s high resolution, free field sound radiation in the near and far field. For a detailed explanation of how the NFS works and the science behind it, please watch the below discussion with designer Christian Bellmann:



A picture of the setup in my garage:
DSC01551.JPG



The reference plane in this test is at the tweeter. XLR input. Volume max. -10dBv. The ports were open (not stuffed).

Measurements are provided in a format in accordance with the Standard Method of Measurement for In-Home Loudspeakers (ANSI/CTA-2034-A R-2020). For more information, please see this link.

CTA-2034 / SPINORAMA:
CEA-2034%20--%20JBL%20305P%20MkII.png


Early Reflections Breakout:
Early%20Reflections.png


Estimated In-Room Response:
Estimated%20In-Room%20Response.png


Horizontal Frequency Response (0° to ±90°):
SPL%20Horizontal.png


Vertical Frequency Response (0° to ±40°):
SPL%20Vertical.png


Horizontal Contour Plot (not normalized):
JBL%20305P%20MkII_Horizontal_Spectrogram_Full.png


Horizontal Contour Plot (normalized):
JBL%20305P%20MkII%20Beamwidth_Horizontal.png


Vertical Contour Plot (not normalized):
JBL%20305P%20MkII_Vertical_Spectrogram_Full.png


Vertical Contour Plot (normalized):
JBL%20305P%20MkII%20Beamwidth_Vertical.png




Additional Measurements

On-Axis Response Linearity
JBL%20305P%20MkII%20FR_Linearity.png

“Globe” Plots
These plots are generated from exporting the Klippel data to text files. I then process that data with my own MATLAB script to provide what you see. These are not part of any software packages and are unique to my tests.
Horizontal Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
JBL%20305P%20MkII_360_Horizontal_Polar.png



Vertical Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
JBL%20305P%20MkII_360_Vertical_Polar.png



Harmonic Distortion
Harmonic Distortion at 86dB @ 1m:
JBL%20LSR305P%20MkII%20--%20Harmonic%20Distortion%2086dB%20%40%201m.png


Harmonic Distortion at 96dB @ 1m:
JBL%20LSR305P%20MkII%20--%20Harmonic%20Distortion%2096dB%20%40%201m.png


Near-Field Response
Nearfield response of individual drive units:
JBL%20LSR305P%20MKII%20--%20Nearfield%20%40%2015cm.png



Dynamic Range (Instantaneous Compression Test)
The below graphic indicates just how much SPL is lost (compression) or gained (enhancement; usually due to distortion) when the speaker is played at higher output volumes instantly via a 2.7 second logarithmic sine sweep referenced to 76dB at 1 meter. The signals are played consecutively without any additional stimulus applied. Then normalized against the 76dB result.
The tests are conducted in this fashion:
  1. 76dB at 1 meter (baseline; black)
  2. 86dB at 1 meter (red)
  3. 96dB at 1 meter (blue)
  4. 102dB at 1 meter (purple)
The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components) instantaneously.
JBL%20305P%20MkII_Compression.png

Based on my results above, it is obvious the output is limited significantly somewhere above the 96dB @ 1m output level. I haven’t confirmed with JBL if this is a built-in limiter, though, I assume it is.


Long Term Compression Tests
The below graphics indicate how much SPL is lost or gained in the long-term as a speaker plays at the same output level for 2 minutes, in intervals. Each graphic represents a different SPL: 86dB and 96dB both at 1 meter.
The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components).
The tests are conducted in this fashion:
  1. “Cold” logarithmic sine sweep (no stimulus applied beforehand)
  2. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
  3. Interim logarithmic sine sweep (no stimulus applied beforehand) (Red in graphic)
  4. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
  5. Final logarithmic sine sweep (no stimulus applied beforehand) (Blue in graphic)
The red and blue lines represent changes in the output compared to the initial “cold” test.
JBL%20305P%20MkII_Long_Term_86_Compression.png

JBL%20305P%20MkII_Long_Term_96_Compression.png






In-Room Measurements from the Listening Position

Below is the actual measured in-room response (with no DSP correction). This is a spatial average taken over approximately 1 cubic foot. The speakers were placed approximately 1.2m from the front wall (not the cabinets; but the actual wall). The listening position was primarily at 1.5m but for this test I measured the response at two different distances from the speakers.
Black = Predicted In-Room Response from SPIN data
Teal = Actual In-Room Measured Response from Main Listening Position at ~ 4 meters
PIR%20vs%20MIR.png

As expected, the predicted in-room response and the farfield response (3.5 meter, blue) line up quite well above approximately 500Hz.



Parting / Random Thoughts
If you want to see the music I use for evaluating speakers subjectively, see my Spotify playlist.
  • Subjective listening varied between the nearfield at 1 meter and the farfield at 4 meters. Subjective listening was conducted at 80-95dB at these distances. Higher volumes were done simply to test the output capability in case one wants to try to sit further away.
  • Output is limited by the internal DSP. From my testing, this occurs somewhere between 96dB and 102dB at 1 meter and results in significant limiting of the output signal. If one assumes 3dB of in-room gain and 6dB from adding a second speaker, this works out to be approximately a maximum volume of 105dB at 1 meter and 93dB at 4 meters, in-room for a pair. It is therefore reasonable to assume that these are not ideal for farfield, long-term high output listening and are best relegated to nearfield or midfield use for higher output levels. If listening at moderate volumes, these make a reasonable solution in terms of output levels.
  • A bit rumbly in the midbass region
  • Depeche Mode - Nice punchy bass but sounds very slightly “rumbly” in the 100-150Hz region.
  • 24k Magic - Bass is punchy but not really “full”; assuming a steep roll off below the 50/60Hz region? (Yep, data backs this up)
  • Soundstage is surprisingly deep (at least, with experience typically only lending itself to the concentric drivers like Kef in this regard).
  • Soundstage width is also quite nice and extends past the sides of the speakers which I believe may come from the wide horizontal radiation pattern of ±70° out to ~13kHz.
  • Peter Gabriel - Sledgehammer - Sounds quite “forward”, setting the HF to -2dB helps.
  • John Mayer’s “Free Fallin” - When he says, “she’s a good girl”, the word “good” tends to jump out of the mix at you in the 1-2kHz region. I used my RTA app to watch for where this peak occurs (in the nearfield, of course). The RTA shows the peakiness between 1.6kHz to 1.8kHz which is exactly where there is a +3dB jump in the on-axis response (apparently caused from port resonance).

The midbass does some things I do not like at all and generally sounds quite resonant. Let me give some specific examples:
  • Howard Jones’ Everlasting Love has a 4-chord progression going in order from:
    • 225 Hz, 180, 150 and 60 Hz (approximately)
    • In the nearfield (~1 foot to mitigate room), the first note sounds very thin and not at all in line with the other notes. Audacity indicates all 4 notes should be at roughly the same audible level. This note - at ~ 225Hz - is right where a dip in the response indicates a possible resonance (cabinet; driver?).
  • Tears For Fears - Everybody Wants to Rule the World at the 1:00 - 1:10 , there is a synth sound around 200Hz that rides along in the background. This sound is brought to the forefront and stands out as a clear resonance in the enclosure. “dum, dummmmm”
  • Wrapped Around Your Finger - Glaring sound from what I assume is the synth (@ 0:26 & 0:30, for example) lights up badly. Again, I believe this is enclosure resonance.
This is most troubling when listening to bass guitars that have notes that span the 100-300Hz region where the data also correlates to showing a downward slope in response >200Hz. Really hard for me to ignore these issues as I hear them. If you tend to listen to music with synth or isolated guitar notes then you’ll likely notice this right away; especially in the nearfield as it is less likely to get swamped out by the room effects.

I understand these are really the “darlings” of the budget monitor scene. For the price, you do get a lot of good performance. However, I think it is important to highlight these concerns as they will ultimately affect a person’s final mix. For example, they may try to EQ out the midbass resonances I noted or the 1-2kHz issues or the HF shelf. If these attempts toward correcting the sound were made then the end user - who may have a much better system without these issues - would get bass that doesn’t sound right, or a 1-2kHz region that doesn’t right. I am providing this information so those who are shopping and/or use this speaker are aware of some of the things that were readily apparent to me with a variety of music genres.

While the two EQ options (low and high-frequency shelf) are nice, I do wish there were additional options for fine-tailoring the sound to a particular location a la the Kali IN-5 I recently reviewed. Though, that would also factor into the cost.

As with anything else, I suggest purchasing these from a retailer who offers a return policy so you can try these out in-home. If you’re in search of such a retailer, please consider using my B&H affiliate link below.

As stated in the Foreword, this written review is purposely a cliff’s notes version. For more details about the performance (objectively and subjectively) please watch the YouTube video.



Support / Contribute
I put a lot of time in to these tests and work hard to provide data that is helpful and useful which means I sometimes have to pay to have other things done that I could do myself (oil change today, etc). So, if you like what you see here and want to help me keep it going, please consider donating via this link. Donations help me pay for new items to test, hardware, miscellaneous items and costs of the site’s server space and bandwidth. All of which I otherwise pay out of pocket. So, if you can help chip in a few bucks, know that it is very much appreciated.

Alternatively, if you are interested in purchasing these speakers, please consider using my B&H affiliate link on my site. It yields me a small commission at no additional cost to you and allows me to keep doing what I am doing.

You can also join my Facebook and YouTube pages if you would like to follow along with updates.
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Thanks,
Erin
 
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hardisj

hardisj

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FWIW, I'll be reviewing these live via YouTube in a few hours. If you want to join and ask questions or just watch me go over all the data and my subjective thoughts, you are absolutely invited. I've not done this before but I'm hoping it goes smoothly because I just don't have time to create and edit videos for every review anymore.

 

LearningToSmile

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I'm loving the compression tests.

Also a bit off-topic but man, always surprises me how bad this series of speakers looks in photos. I have my 308's sitting right here and while the texture difference is still there, it's a lot more subdued in person. I bought them despite the looks but they kinda grew on me once I actually saw them in real life.
 

Bullwinkle J Moose

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Corrections to Manufacturer's details:

Not a 5" midbass driver
Actually 4"

and there is no "precise Imaging"
------------------------------------------

also uglier than the 1st gen and no real improvements over 1st gen that justify $100 price increase

Fact checking welcomed!
 
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dmac6419

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I'm keeping mines,listening to em right now,sounds good near or far.
 

napilopez

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Thanks for the review @hardisj! It's interesting to see these again as it was I believe the first speaker Amir measured, so all his refinements weren't in place yet.

The 225 Hz resonance is interesting -- hard to see anything there in the spin other than a small dip (the one at 1.7ishK is obvious). But you can see in MZKM's normalized horizontal plot that there is some clustering going on at that frequency -- just hard to imagine such a small thing would have such an audible effect!

Anyway, seems to me like using a HF shelf above 1.5ish kHz would be a good idea.

Corrections to Manufacturer's details:

Not a 5" midbass driver
Actually 4"

and there is no "precise Imaging"
------------------------------------------

also uglier than the 1st gen and no real improvements over 1st gen that justify $100 price increase

Fact checking welcomed!

Woofers are never actually the size that you see. I.e, if you measure any 6.5-inch woofer, it is almost always ~5" in reality.
 

MZKM

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restorer-john

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@hardisj Re: your compression tests.

2 minutes and 4 minutes in my opinion is hardly 'long term'. At 4 minutes, the magnet structures won't even be warm. The voice coils will shed their heat much faster to cold adjacent pole pieces/magnets. The electronics (amplifiers) will be barely above ambient and any crossover components (in passives) will not be stressed, letalone warm.

These JBLs are a low power system anyway so it probably doesn't matter so much, but when you test higher power (rated) speakers at much higher SPLs, the term should be considerably extended to determine the effects of temperature related compression in a more useful (and related to typical used-case) manner.

But you do live in a neighbourhood and don't want to upset your neighbours.
 
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MZKM

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@hardisj Re: your compression tests.

2 minutes and 4 minutes in my opinion is hardly 'long term'. At 4 minutes, the magnet structures won't even be warm. The voice coils will shed their heat much faster to cold adjacent pole pieces/magnets. The electronics (amplifiers) will be barely above ambient and any crossover components (in passives) will not be stressed, letalone warm.

These JBLs are a low power system anyway so it probably doesn't matter so much, but when you test higher power (rated) speakers at much higher SPLs, the term should be considerably extended to determine the effects of temperature related compression in a more useful (and related to typical used-case) manner.

But you do live in a neighbourhood and don't want to upset your neighbours.
96dB RMS for 2min seems like enough. That’s damn loud.
 

restorer-john

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96dB RMS for 2min seems like enough. That’s damn loud.

It's not about level, it's about thermal compression from changes in the resistance, magnetic characteristics and materials. The voice coils experience rapid temperature rise, but when surrounded by cold magnetic structures, they dissipate that heat extremely quickly. They cool virtually instantly the signal stops. As the structure heats up over a long period, the ability to shed VC heat becomes less and the compression effects become more obvious.

Long term testing results in speaker magnet/baskets so hot they can almost burn your hand. (not saying he needs to go that far).

It's a bit like short term maximum power amplifier Po 'tests'. They tell you nothing about how the amplifier will actually perform long term.

These are marketed as 'studio monitor'. :facepalm: In reality, they are a cheap 2 way with 2x41W high THD class D amplifier pairs in a small box. They will be absolutely hammered by bedroom 'producers' and extended testing should be considered as a more typical use case IMO.
 

Bullwinkle J Moose

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Thanks for the review @hardisj!

Woofers are never actually the size that you see. I.e, if you measure any 6.5-inch woofer, it is almost always ~5" in reality.

YES, woofers ARE actually the size that you see!

You see a 4" woofer

Now let me just stick this 24" monitor in an 80" frame and I'll sell you this 80" monitor

Why not measure the metal frame of the woofer as well?

PooF......Now it's a 6" woofer

If you are going to measure the surround just to pad your specs, then show some consistency and call the tweeter 1.25"
or measure the horn and call it a 6.3" tweeter

I don't care how manufacturers pad the specs
I measure what they actually are
 
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hardisj

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2 minutes and 4 minutes in my opinion is hardly 'long term'. At 4 minutes, the magnet structures won't even be warm. The voice coils will shed their heat much faster to cold adjacent pole pieces/magnets.

I understand the concern. However, you could ask ten different people how long they think the test should be run and you'd probably get ten different answers. However, I based my method off a few things:
  • IEC 60268-21 §17.1 has a couple different max SPL settings (depending on short term vs long term). The long term test is 1 minute of signal, 2 minutes rest. I have quoted a portion of it below:
- Excitation time (T): Time = 1 s​
- Pre-excitation time (Tp): Preloops = 59x​
- Stimulus time = 60 s Excitation time + Preloops according §18.4.1​
- Averaging = 1 (Time * Avergaing = T_s)​
- Pause = 120 s according §18.4.1​
- Repeatition = 60 times​
  • Scan-Speak does 28 minutes total of 1 minute on, 2 minutes off. Weighted pink noise with a crest factor of 2dB (my CF is 12dB). Link.
  • My recent discussion with Earl Geddes where he recommended one minute on, measure, another minute, measure.

I took a conglomerate of these and came up with test, 2 minutes, test, 2 minutes, test. I chose the levels because I believe they are rooted in reason. I think 2 minutes of 86dB is close to what people will listen to (when you factor in two speakers in a room). The 96dB is on the higher end and is more of a stress test. Others are welcome to adopt a similar methodology and tweak as they see fit. To date, though, no one is doing anything remotely like this compression test (long or short term). And, IMHO, it is far more important data than distortion measurements (which I still provide, just for the heck of it) because the frequency response is changed and that is clearly audible.

I'm not saying running the test longer wouldn't be useful. I'm saying I don't know that it is entirely necessary and - based on the fact the IEC is less stressful - I like my method more. Plus, it can be run pretty reasonably. It's not just a "better than nothing". IMHO, it's a "rational and useful" method. Call me biased. But I'll stick with this method until I have convinced myself there's a reason to change. If you look at the below graphic you can see that even 2 minutes is enough to change the response of "lesser" speakers:

PreSonus Eris E3.5_Long_Term_96_Compression.png



That's my $0.02 on the subject. As I said, if others want to run a similar test they are certainly more than welcome to change their parameters as they see fit.
 
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hardisj

hardisj

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It's not about level
and extended testing should be considered as a more typical use case IMO

Well, it is about levels.

At 1 meter:
86dB at 1 meter anechoic for a single speaker ~ 95dB at 1m for a pair in a room.
96dB at 1 meter anechoic for a single speaker ~ 105dB at 1m for a pair in a room.


At 4 meters:
86dB at 1 meter anechoic for a single speaker ~ 83dB at 4m for a pair in a room.
96dB at 1 meter anechoic for a single speaker ~ 93dB at 4m for a pair in a room.
 
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