JBL 705P / 708P

[Music1969]

Hi all

Apologies for the silly question, but since the 705/708P both have digital inputs, I assume these use digital crossover which cannot be by-passed?

So best to feed these via digital AES3 and NOT analogue (to avoid double D to A conversion)?

 

[andreasmaaan]

Hi all

Apologies for the silly question, but since the 705/708P both have digital inputs, I assume these use digital crossover which cannot be by-passed?

So best to feed these via digital AES3 and NOT analogue (to avoid double D to A conversion)?

That's correct, yes.

OTOH, if the ADC is well-implemented (which I suspect it is), there may not be an audible difference when fed from a decent DAC.

 

[Deleted member 2944]

The ADC is transparent, in my listening.
One potential negative aspect of using the AES input is (depending upon how your head end operates) you can get some disconcerting snaps/pops/etc during lock/unlock/lock transitions in the data stream. These could be associated with start/stop, track switches, SR or bit depth changes, etc, etc.

Dave.

 

[12B4A]

ADC used in 7 series.

 

[bigx5murf]

I wonder how these compare https://www.gearnews.com/ex-jbl-crew-kali-audio-intros-lp-6-lp-8-budget-studio-monitors/

 

[andreasmaaan]

I wonder how these compare https://www.gearnews.com/ex-jbl-crew-kali-audio-intros-lp-6-lp-8-budget-studio-monitors/

They are competitors more to the JBL LSR3xx series in that price range and with those specs.

 

[xyvyx]

Yes. It’s compatible with AVB and Dante.

So do AVB devices from different vendors tend to play nicely together?

I just purchased a pair of the 708Ps..... they'll be delivered Thursday and my original intention was to connect them to the balanced outputs from my DAC. But upstream of my dac is a Motu LP32 which is fed from a couple PCs and & Chromecast audio (RIP) via toslink. But if I could send the signal to the JBLs via AVB/ethernet, that'd be kinda cool.... Looks like maybe I could purchase a small AVB / AVNU compliant switch to connect the speakers with the Motu, then that switch would talk to the rest of my network via standard ethernet.

The signal wouldn't likely be any better than what I could send via the AES digital ports, but if I could also control their filters via. Audio Architect over the same interface, that just sounds way cleaner. From what I've been reading, the whole network audio landscape looks like a mess... HiQnet, CobraNet, Dante, AVB, BLU-link, AES67. Lots of standards, questionable compatibility.

FWIW, I've been reading this to get a better understanding of what AVB is:
https://adn.harmanpro.com/software_...ystems_Guide_To_Audio_Networking_original.pdf

 

[12B4A]

I've not seen anything to indicate that the 7Pseries HiQNet port can be used to receive audio data.

 

[jhaider]

I've not seen anything to indicate that the 7Pseries HiQNet port can be used to receive audio data.

They didn’t incorporate Blu-link into the 70XP speakers?

 

[12B4A]

If they did, they don't mention it anywhere in the manual nor in their promotional material. This is what describes the RJ45 port:

1. HiQnet PORT – This port allows feature updates as they become available

 

[SIY]

I wonder how these compare https://www.gearnews.com/ex-jbl-crew-kali-audio-intros-lp-6-lp-8-budget-studio-monitors/

I have a pair of LP-6 in for review in AudioXpress. I can't say too much in advance beyond "if you get a set of these, you will not be unhappy." Input is analog, so if you need AES/EBU or SPDIF or USB, you'll want something else.

 

[Sal1950]

I have a pair of LP-6 in for review in AudioXpress. I can't say too much in advance beyond "if you get a set of these, you will not be unhappy." Input is analog, so if you need AES/EBU or SPDIF or USB, you'll want something else.

A sneak preview? LOL

 

[Jaimo]

My 708P's arrived yesterday. It took me a couple of minutes to remove the LSR308's and hook up the new puppies. Wife was confused "they look almost the same as your old speakers" until I played Santana's "Maria Maria" and cranked up the volume...

This is likely going to be my party trick for the coming weeks.

I ran a set of REW Curves on the 308's and will do the same for the 708's as soon as I can stop listening to music.

 

[Krunok]

About the best you can do is to treat one reflection at one single point with a FIR filter. Move the head a bit and it will change, especially in the higher frequencies where wavelengths are short.

I don't agree with this. After I did correction of my speakers response at LP wherever I make measurements the response above Schroeder frequency (in my case it's app at 300Hz) stays consistenty flat throughout the entire room. Only the response below 300Hz changes but it is also better in practically all positions than it was before correction. Step and phase response also measures much better than before correction, so my listening impressions and measurements after the correction confirm what @mitchco said.

When doing room EQ higher frequencies are usually corrected only slightly with low Q or are not corrected at all. Basis for correction are usually measurements taken in multiple points so it's not that response is optimised for the point where your head is and not for the point where your head would be if you move it a little, and that is what I experience - I don't hear any change in higher frequencies when I move my head a bit, neither in LF as well.

No sudden changes will happen when you move your had a bit, either with correction or without it, assuming you did correction the right way. Even when walking around the room I don't hear any sudden unnatural changes.

 

[Bjorn]

@Krunok
If you only care about frequency response, that's true. But the the reflections will not really be dealt with and you actually end up introducing time distortion. Personally I don't think that sounds good or natural. But I can't argue with what you prefer.

 

[Krunok]

@Krunok
If you only care about frequency response, that's true. But the the reflections will not really be dealt with and you actually end up introducing time distortion. Personally I don't think that sounds good or natural. But I can't argue with what you prefer.

Well, personal preferences surely exist but I believe here we are discussing technical aspects based on measurements and not personal preferences. What exactly do you mean when you say "time distortion"? As I did correction not only in frequency domain but in time domain as well I measured great improvement in step response, phase response and GD. So what "time distortion" do you think I introduced with correction and why it is not showing in measurements?

Certainly the things would be even better if I had a chance to do room treatment to reduce reflections, but that is not applicable as in my case it is my living room where I listen music the most.

 

[Sal1950]

@Krunok
If you only care about frequency response, that's true. But the the reflections will not really be dealt with and you actually end up introducing time distortion. Personally I don't think that sounds good or natural. But I can't argue with what you prefer.

Since the severity of the reflection situation will vary drastically from room to room and speaker setup, isn't the truth of the time distortion issue a large variable? In some rigs it can be huge while in others only a minor influence?

 

[Krunok]

Would step response be a good measure of "time distortion" as room reflections and drivers time (mis)alignement would show there?

 

[mitchco]

Timing response of my JBL/Rythmik sub 3-ways before any timing (i.e. excess phase) correction:

Step response over 200ms with mic at LP in my room. Shows a maximum phase room reflection 30ms after the direct sound. Side note, subs are negative going polarity.

After correction:

Aside from the drivers time aligned, the woofers/subs follow the target response, while inverting the polarity of the subs and removing the maximum phase room reflection. Note this is an ideal "minimum phase" loudspeaker response at the LP.

Folks forget that for a given impulse response can be split into its minimumphase and excessphase parts. The minphase part describes the given frequency response whereas the excessphase part describes the timing. Both can be corrected independently using a FIR filter. And it is not just at one point in time either. In my book I show both frequency and timing response stays consistent across a 6ft x 2ft listening area with 14 validation measurements.

Details with verification measurements in this article. This article shows how timing correction can reduce low frequency group delay at the LP.

Finally, this article includes binarual recordings of the above speaker system, comparing to KEF LS50 with sub. People can hear for themselves that so called digital loudspeaker and room correction does not sound "weird or unnatural".

 

[Bjorn]

There's another thread that was started about room correction and I suggest you continue the debate there.

But bottom line is that showing measurements of the speaker and driver on-axis has no relevance to what we're talking about. It's simply not possible to correct myriads of reflections arriving simultaneously or at different times with different spectral content from different angles with a software in way that works. That's simply impossible without making something else much worse. Not to mention that when taking into account superpositions between drivers/speakers, and the fact that even if you actually could effectively cancel out reflections ; it wouldn't be the psycho acoustically correct way of doings things. With treatment you are trying to achieve different design goals with different type of treatment. Something not possible in any other way.

The difference between a well treated room and something based on "room correction" is completely night and day. One sounds completely unnatural and weird if one corrected much of what's non minimum phase behavior and the other sounds natural and spectacular.

The irony here is that despite that some designers of room correction softwares say it works to correct the room and reflections, they also say you need treatment for a really good result. Where is the logic in that if the room correction truly worked as they say? But the fact is that it doesn't and even some of the speaker correction that is done is something one should ideally avoid.