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JBL 308P MKII 8-inch 2-way monitors - first impressions

ripvw

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#1
I purchased these last week from B&H for $299 - sale now over - they were $200 cheaper than normal due to JBL's national promotion. They replaced my Presonus Eris 5/Temblor T10 2.1 package that I purchased for $500 almost a year ago. For details see this post:

https://www.audiosciencereview.com/forum/index.php?threads/presonus-eris-e5-temblor-t10-review.4089/

So why the change? Family members who were ok with the sound of my system suddenly began noticing the sub. After a while I just shut the sub off to placate them but found the 5-inch monitors a bit thin on their own. I ended up giving my musician godson the package with the Topping DX7s and Sennheiser HD600 and moved on to the JBLs. So far no complaints from the relatives...

specs and photos here:

http://www.jblpro.com/www/products/recording-broadcast/3-series-mkii/308p-mkii#.XRwVUi2ZOKV

Pro review here:

https://www.mixonline.com/technology/review-jbl-professional-308p-mkii

I placed the JBL's on insanely heavy 32-inch stands - 70 lbs of sand. As usual I used Blu-tak to "weld" the monitors in place resulting in tweeters at ear height with the carpet spikes at the lowest position. I angled the rear-ported 308P's so that they are about a meter from the rear wall and set the Boundary EQ to 0db, resulting in nice tight bass. No thin sound here - the 308P's do a very convincing job of reproducing bass on rock and pop recordings. While the 308P's can sound bright with poorly recorded albums for the most part they are simply highly detailed so I left the HF Trim setting at 0db as well. I used pink noise to calibrate the monitors and used the LEDR "shaker" tones from a Chesky CD to test imaging - they aced the test!

https://www.stereophile.com/features/772/index.html

Music sources include ripped CD's using Apple Lossless with iTunes at 44/16 and Tidal tracks at 44/16 and 96/24 and so far I've focused mostly on rock along with familiar male and female pop vocals. Overall I'm very happy with the way the JBL's sound especially for the price - although they do look almost comically large sitting so close to the listening position. I do not hear any hiss from the tweeters no matter what the circumstances. It could be that my 63 year-old ears simply don't register the noise or that the problem does not exist with my pair. I'll get some younger ears to check them out ASAP and report back. Used with my 2018 iMac 27, Khadas Tone Board, JDS Labs Atom and RCAs from Blue Jeans Cable and XLR/RCA cables from Benchmark.
 
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Name

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#3
I have them and I can only hear a hiss if I have my ear basically touching up against the wave guide. It has the effect of putting your ear inside a sea shell. That's the only noise I get. I can't hear it at 6" away.
 

Name

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#4
This is a snapshot of a frequency sweep I did in REW with the UMIK-1 mic. I have the mic at listening position between where my ears would be. I have the svs pb16 ultra crossover to the JBL 308p's at 80hz 12db slope. I am running the pb16 ultra with one port plugged in extended mode for low end extension. I have not done any room correction, I have only done volume correction to match sub to speakers. Does this look pretty good? (1/6th smoothing)
 

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ripvw

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#7
Thanks for the report. Would be good to get confirmation on the hiss as my LSR 305 MKIIs definitely have them.
The 308P and 306P both use different amps than the 305P - 56 wpc LF/HF vs 41 wpc LF/HF - perhaps the smaller amp is noisier. I'm still going to have my 30-year old niece take a listen tomorrow - she's not a rocker like I was at that age so her ears will likely be up to the task...

UPDATE: my niece just confirmed that there is hiss - BUT she had to put her ear within 6-inches of the tweeter to hear it. This is with the gain on the 308P at full tilt. Increasing or decreasing the gain from the JDS Atom made no difference so this is a speaker issue...
 
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Sasha

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#9
The 305p MK2 I have here are pretty noisy when you get close - and towards the top of their volume dial, you get hum to add to the hiss.

Sound great from a couple of metres away though! :)
 

Name

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#10
Are you using balanced cables? You shouldn't have a hum, but only a slight hiss from the tweeter.
 

daftcombo

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#11
Thanks for the report. Would be good to get confirmation on the hiss as my LSR 305 MKIIs definitely have them.
From which distance do you have hiss?
Volume knob at which position?

Btw LSR 305 mkII don't exist.
It's either LSR 305 or 305p mkII.
 
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#12
Originally my 308p had more hiss, and also had a hum that increased as the volume pot increased... It was annoying and sounded like shit to me. I was using unbalanced cables though. When I went to balanced cables, the hum went away, and the hiss decreased so much I could only hear it within a few inches and it is a faint seashell sound. I hope that is helpful to someone. Use balanced cables.
 

daftcombo

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#13
Originally my 308p had more hiss, and also had a hum that increased as the volume pot increased... It was annoying and sounded like shit to me. I was using unbalanced cables though. When I went to balanced cables, the hum went away, and the hiss decreased so much I could only hear it within a few inches and it is a faint seashell sound. I hope that is helpful to someone. Use balanced cables.
Xlr or Tlr?
 

Blumlein 88

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#15
On LSR's that hum with an unbalanced to balanced connection I've seen two issues contribute.

One is having the speaker plugged into a different circuit than the source component. Using a cheater plug to lift the third pin will greatly diminish or eliminate this. Technically not a safe condition, but could be used to determine source of the hum.

Another is feeding unbalanced you need some fair amount of shielding. I've run across some XLR cables that had one end adapted for this purpose or used an adapter and there was hum pickup because the XLR cable was unshielded. Well shielded balanced to unbalanced cables greatly reduced hum pickup. The Monoprice premium cables that are RCA to XLR are fine for this. I've also used Livewire cables that were TRS to TRS with an RCA adapter on one end which didn't pickup hum.
 
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#16
"One is having the speaker plugged into a different circuit than the source component. "

>>> I made sure that I was not doing this.... This was definitely not the issue for me.

"Another is feeding unbalanced you need some fair amount of shielding."

>>> This could have been the culprit...

The easiest fix for me was to just run balanced and problem solved! :) I have the Focusrite Scarlett 2i4 so why not? I ended up later getting an Integra pre/pro model DHC-80.2. Going to do 5.1 with these.
 

daftcombo

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#17
"One is having the speaker plugged into a different circuit than the source component. "

>>> I made sure that I was not doing this.... This was definitely not the issue for me.

"Another is feeding unbalanced you need some fair amount of shielding."

>>> This could have been the culprit...

The easiest fix for me was to just run balanced and problem solved! :) I have the Focusrite Scarlett 2i4 so why not? I ended up later getting an Integra pre/pro model DHC-80.2. Going to do 5.1 with these.
I have a Scarlett 2i4 too and am considering getting a pair of 305p mkII for the computer to replace a pair of Altec Lansing.
Do you set the monitors at max volume and control them with the 2i4 volume knob?
 
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#20
The noise pretty much completely disappeared when I went from the focusrite to the jbl's via 1/4" TRS to XLR cables. The only noise I have that does exist is when my head is within a few inches of the tweeter and it sounds almost exactly like putting your ear up to a seashell. I don't understand how anyone would be bothered by this lol.
 
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