JBL 708P Review (Professional Monitor)

[sarumbear]

Conclusions
Technically and objectively, the JBL 708P is near perfect.

Do we have a Billionaire member in the forum who can dropship one of these to @amirm?

I would love to finally read "Technically and objectively, this speaker is perfect!"

https://www.jblsynthesis.com/products/loudspeakers/series/summit-series/DD67000RW-.html?dwvar_DD67000RW-_color=Cherry-Japan-Current&cgid=summit-series

 

[LeftCoastTim]

I'm in the US, and the KH310 is too expensive.

On Amazon, KH310 is $2250 each, vs $1800 each for the 708p.

I got my 708p for $1000 each as b-stock directly from Harman (with warranty). Harman has factory sales like this a few times a year, if you subscribe to their mailing list.

 

[bluefuzz]

Oh boy. I'm done at 7.mumble kHz.

Remember, that's only a little more than an octave missing from best possible hearing. Barely noticable. All you're missing is the top end of cymbal crashes and bad digital reverbs that just give you a headache anyway ... ;-)

 

[peanuts]

I would love to finally read "Technically and objectively, this speaker is perfect!"

doubt it. tweeter it crossed at 20khz 4th order, polars will collapse in the high-end

 

[Spocko]

Not bad, but I'm not sure people know JBL's pricing in Europe. Here, it's 2100€ new vs 1750€ for the KH310 and 1800€ for the 8350A. Which have better performances (distorsion, port and on-axis FR) with less known reliability issues.
Again, not to say that this is a bad speaker, but the competition is simply too good at that price point.

Amazing how much cheaper the Genelecs are over there and for that price, I'd choose the 8350A all day long.

 

[LTig]

Amazing how much cheaper the Genelecs are over there and for that price, I'd choose the 8350A all day long.

And I the KH310. 3-way beats 2-way.

 

[LTig]

The 708P has a compression driver with waveguide. This thing should easily deliver 100dBSPL (100dB/1W/1m).
If the amplifier for the tweeter would deliver only 50W of power (THD <=1%), a maximum sound pressure of 100 + 10*log50 = 117dB would result.

Therefore, the 250W amplifier power for the compression driver is total overkill and completely unnecessary. But Class D amplifier power can be had cheaply, so why develop another power amplifier.

Correct- and I think the reason is to use one big power supply for both amps instead of 2 smaller ones. Should be cheaper.

 

[LTig]

Especially when the wife leaves you because they are so darn ugly

ROTFL YMMD.

I am already in this heaven (O300D, predecessor of KH310, and a sub) and my wife didn't leave me. I actually let her choose between keeping the Magnepan MG 1.6 or getting the O300D. Maybe she is blind.

Later I added the grills so the front plate is hidden from view but actually I preferred them w/of grill. Better safe than sorry.

 

[LTig]

Not bad, but I'm not sure people know JBL's pricing in Europe. Here, it's 2100€ new vs 1750€ for the KH310 and 1800€ for the 8350A. Which have better performances (distorsion, port and on-axis FR) with less known reliability issues.
Again, not to say that this is a bad speaker, but the competition is simply too good at that price point.

I think it's a no brainer. If budget is a concern then in the EU get the KH310 or 8050, in the US the 708p. Don't know how prices are in the UK, now after Brexit.

 

[AurekV]

I have a pair of 708Ps and there is very little hiss. However, there is tonal noise at high frequencies on both of mine at 11 and 16.5 kHz. When within about 1.5m of the speaker (given my relatively young age and undamaged hearing) these tones are audible and quite irritating. I'd imagine others could hear this closer up or in quieter rooms who are older than me (in my early 20's) because of the 11 kHz tone. It reminds me of "The Mosquito" devices which emit a 17 kHz tone to essentially irritate young people into leaving an area.

I would like to see better S/N parameters, especially of the woofer section. I wonder why those powered speakers are usually noisy. At least it seems they do not use class D for the tweeter (appreciated), from their website specs. Anyone measured resonances of the 12mm plywood case? I am still not sure that I would want this as a hifi speaker.

Specs in the manual
View attachment 110092

 

[BostonJack]

Welcome to the club (of semi-deaf sports shooters) About the same here, the probably worst for me were my early years with proper protection not available. Sorry for OT. BTW, the test is probably not very accurate, unless you have a very quiet room.

I've been avoiding professional audio tests for years now. Waiting for hearing aids to catch up to my expectations. Years of amateur woodworking without hearing protection for most of it hasn't helped either.

 

[Spocko]

And I the KH310. 3-way beats 2-way.

Absolutely, that mid-driver is to die for, and would be my choice for 2 channel listening, but as I'm using these for home theater applications, the KH310 is a bit harder to place.

 

[LTig]

Absolutely, that mid-driver is to die for, and would be my choice for 2 channel listening, but as I'm using these for home theater applications, the KH310 is a bit harder to place.

Why this? They even have two (I think M6 or M8) screw holes on each side for mounting on wall or ceiling (using a proper holder).

 

[warthor]

Sorry for the newbie question: Can someone explain to me why this speaker received a 5.0 preference rating with such good objective results? Many speakers out performed in when using preference score alone. (I do not mean this as a troll question, I am wanting to understand what I am missing).

 

[pierre]

Mind you that positive PEQ cause ringing in time domain which can be audible especially at higher Qs and such higher frequencies which is something that the Harman score doesn't take into account:
.

Thanks for the feedback.

I have been looking for which level of pre ringing is audible. Do you have a reference I could read? The algorithm has a flag to generate only negative gain for Peak biquad.

https://support.genelec.com/hc/en-u...-does-GLM-not-fix-dips-on-frequency-response-

Dips created by cancellation in room should not be corrected. OK with that. But here we are trying to correct an anechoic measurement so I think this is not relevant. I had in mind to EQ below Schroeder with a normal room EQ and above with correction on Amirm's measurements.

Which is also obvious when taking into account that those are DSP loudspeakers, so if all problems could be fully corrected by DSP the experienced engineers who tuned them would have already done so.

Maybe. Why do they not have a as flat On Axis as Genelec or Neumann if they can easily do it and their own ranking system push them to do it?

 

[pierre]

What is the target tilt for estimated room responses? 13 dB from 20 to 20 kHz?

Here I am optimising for LW (flatness, target -2dB from 300Hz to 20kHz) and having Early reflections as flat as possible but without a target.

 

[pierre]

Sadly seems that, in common withe all the up market JBLs I have investigated in the last 20 years, it is pretty well unavailable here in the UK. The importer website is hopeless.

JBL pro is well represented in Europe. You can easily find all studio monitors (M2 included).

 

[Dj7675]

I have an Atmos setup in my Home Theater with 5 of the 705i speakers (JBL In-Ceiling, JBL Subs), and I've been extremely impressed with them. The "install" versions NEED Eq to sound right, but just a super clean sound that punches way above its size. In my opinion, there is no comparison to the 3 series. I have those as well, and while a good speaker, not close to the 7 series in performance and subjective sound quality.

What do you use for eq? Harman amps with built in eq?

 

[TimVG]

Do we have a Billionaire member in the forum who can dropship one of these to @amirm?

I would love to finally read "Technically and objectively, this speaker is perfect!"

View attachment 110139

https://www.jblsynthesis.com/products/loudspeakers/series/summit-series/DD67000RW-.html?dwvar_DD67000RW-_color=Cherry-Japan-Current&cgid=summit-series

Here's the K2 S9900

 

[thewas]

Thanks for the feedback.

I have been looking for which level of pre ringing is audible. Do you have a reference I could read?

You are welcome, unfortunately don't know of a paper which has tested which value regions are audible, possibly as they depend also on several other factors.

Dips created by cancellation in room should not be corrected. OK with that. But here we are trying to correct an anechoic measurement so I think this is not relevant.

I am referring not to the part of room dips but the part that positive PEQs mean ringing in time domain.

Maybe. Why do they not have a as flat On Axis as Genelec or Neumann if they can easily do it and their own ranking system push them to do it?

That was my point, if any resonance wiggle could be just corrected with EQ without negative side effects they would probably have done it. Myself I used to be till recently a big eq fan, equalising everything to look fantastically flat, till I realised that usually it made things sounding worse, which is why I now carefully listen to Genelecs, REW and others recommendations which I used to ignore.