JBL 308P and 708P

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Lego
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Re: JBL 308P and 708P

Post by Lego »

Defender wrote: 2022-01-25 22:48 yes I did and I didn’t enjoy it as much. My conclusion is now when the bass is not tamed enough it might be not the optimal position. I positioned them now more far away from each other and the bass problems are away and the slight harshness in the upper frequencies also.

Moved from them from 1.45Meters to 1.70Meters distance. They are really special.
That's good news,have you managed to get rid of the hum?
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Re: JBL 308P and 708P

Post by jajo »

Defender wrote: 2022-01-21 14:43 Jajo you say most bass problems come from non perfect positioning of speakers.
What is your experience when you have a „seem to be perfect“ distance from the wall which is very musical but bass boomy. Is there another distance from the wall which is musical but without the bass boominess? Or does the bass boominess might go away with finding another distance between them. I also found already a very musical distance between them but it still has bass boominess.
Did it happen to you that you found more than one quasi sweet spot?
There can be more than one good position that needs to be evaluated against each other, yes. This is not just the case with the JBLs but with all speakers. In most cases one of them will be clearly better.

However never focus on the sound when finding the optimal speaker position. Don't listen for "bass boomyness" or such. Ignore that and focus on musicality. My experience is that in the optimal position (musically) I am not troubled with sound related problems. But if I search for a position where a specific sound related problem goes away, I rarely find the optimal position musically.
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Re: JBL 308P and 708P

Post by V.A.MKD »

Defender wrote: 2022-01-25 22:48 yes I did and I didn’t enjoy it as much. My conclusion is now when the bass is not tamed enough it might be not the optimal position. I positioned them now more far away from each other and the bass problems are away and the slight harshness in the upper frequencies also.

Moved from them from 1.45Meters to 1.70Meters distance. They are really special.
Excellent Defender, great to hear that you find solution ...
Music First ...
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Re: JBL 308P and 708P

Post by Defender »

the faint hum is still there - but I can hear it only if I put my ear close to the bass driver. The noise of the HF unit is also still there and I can hear it at my listening position but I can live with that too.
But thats all with the Akurate DS connected as only source (I am missing one power socket to connect all … 2x Sagatun, 2x JBL308 and either DS or Radikal and Entity) so meaning in case there is a gound loop through the Akurate DS it can only be taken away if I only connect the Entity to the Sagatun.

But I like to run in the RCA=>XLR cable first before I move to higher musicality. Its always nice to have another upgrade to look forward to (switching from DS to LP12).
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Re: JBL 308P and 708P

Post by Lego »

Defender wrote: 2022-01-26 13:31 the faint hum is still there - but I can hear it only if I put my ear close to the bass driver. The noise of the HF unit is also still there and I can hear it at my listening position but I can live with that too.
But thats all with the Akurate DS connected as only source (I am missing one power socket to connect all … 2x Sagatun, 2x JBL308 and either DS or Radikal and Entity) so meaning in case there is a gound loop through the Akurate DS it can only be taken away if I only connect the Entity to the Sagatun.

But I like to run in the RCA=>XLR cable first before I move to higher musicality. Its always nice to have another upgrade to look forward to (switching from DS to LP12).
Unplugging the Ds and removing adapters will get rid of hum.I think plugging DS in different wall socket might get rid of hum but musicality will plummet
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Re: JBL 308P and 708P

Post by Defender »

the adapters are out its now a cable which Tom soldered for me so if there is a ground loop from the DS I can only get rid of it in getting something done with the JBLs which I am ready to do but I will check without the DS first.

I always thought if the Sagatun could have an option to switch of the input 1-4 also from the ground would be an option. But that might influence musicality more than the advantage it brings just in case there is a ground loop for one of those devices.

BTW would I get rid of the ground loop if I would use a cheater plug for the DS rather than two cheater plugs for the JBL‘s?
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Re: JBL 308P and 708P

Post by ThomasOK »

I asked Fredrik about having the switching disconnect the ground as well as the hot once. It was a definite no-no and would cause more problems musically than it would fix.
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Re: JBL 308P and 708P

Post by Defender »

thats what I thought too and as it will only help if there is a real problem and than it would only help the first source to sound better its too many ifs. Thank you again for the cable its running in nicely - difficult to imagine any other cable would sound better
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Re: JBL 308P and 708P

Post by Defender »

here is an update from my side - the 308‘s perform exceptional when carefully installed they are simply the most musical speaker I have heard independent of price.

all what is important was said by Jajo before but do yourself a favor and take care with the installation. They need a good connection to the floor and their position need to be optimized to the last millimeter.
Everyone who just placed them somehow to sound good enough is giving away a lot of joy and pleasure.

Jajo if you happen to be anytime in Germany near me I owe you a beer or wine or whiskey. This a serious invitation.

Yes there are speakers which might sound more impressive at the first listen but the 308 convince you the more music you hear.

The good thing about them and their price is that I dont worry to place them on spikes and the spikes poke dents in the bottom of the speaker as they give it back with even better performance.

@Spannko: I dont think that missing dynamics has something to do with run in but rather with the right positioning + connection to your floor and the using of RCA=>XLR adapters.

Thank you very much for giving that secret away.
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Re: JBL 308P and 708P

Post by Offerdal »

I have a basic question. Is the JBL 308 mkI Also Called 308 lsr and the P came first when the mkII arrived?
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Re: JBL 308P and 708P

Post by Defender »

JBL LSR308 - the p stands for powered but doesn’t appear in the product name.
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Re: JBL 308P and 708P

Post by Fred11 »

Here is my newest 308-project. I have a very strict general in my house and I also like design myself, so it might be sound-wise compromising. But it also sounds very good! I will try to work out the Dropbox clip and post some. I thought about Klipsch Heresey when I made the stands. I like Heresey from a vintage-design point of view.
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Re: JBL 308P and 708P

Post by Spannko »

I love the retro speaker look too Fredrik. How are they sounding? Have you had to reduce the bass due to the corner loading?
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Re: JBL 308P and 708P

Post by Fred11 »

Thank you: ) They Play very well. Yes, bass is redused. I will test music more systematicly when I have time.
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Re: JBL 308P and 708P

Post by Azazello »

3677 back, now with Tundra mono 2.2.

They are staying.
Last edited by Azazello on 2022-02-13 22:30, edited 1 time in total.
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Re: JBL 308P and 708P

Post by matthias »

Azazello wrote: 2022-02-10 14:24 3677 back, now with Tundra 2.2.
They are staying.
Congrats,
I press the LIKE button :-)
Last edited by matthias on 2022-02-11 13:15, edited 1 time in total.
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Re: JBL 308P and 708P

Post by tokenbrit »

Azazello wrote: 2022-02-10 14:24 3677 back, now with Tundra 2.2.

They are staying.
Congrats. Is that at the expense of the LSR308s, and are you still waiting on the 708Ps?
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Re: JBL 308P and 708P

Post by Lego »

Azazello wrote: 2022-02-10 14:24 3677 back, now with Tundra 2.2.

They are staying.
any chance of some clips Azazello,please?
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Re: JBL 308P and 708P

Post by Defender »

yes would be interested to hear clips.
how high above the floor have your JBL308 have been placed?

I dont question the ability of the Tundra Monos together with the 3677 but your setup of the JBLs 308 looked like they are positioned too high.

I tested stands yesterday which are 63,5cm above the floor and it was clearly worse than the other stands which are 60.5cm.
Mainly with respect to voices and with respect to bass performance which seemed like more body but much more unprecise. My room hight is at 4.50Meters if that makes a difference.
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Re: JBL 308P and 708P

Post by u252agz »

I have just moved my 308s to 60cm height ( distance between the two 170 as before) and they sound better than the previous 53 cm.

They were still very good at 53cm ( especially with Kalla) but definitely more musical at 60cm.

Room height only 2.5m.
Kalla/Sag M/Tun M3/242/LP12/Slip7

Kalla/Giella Pi/JBL308/RS2e

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Re: JBL 308P and 708P

Post by Defender »

uups my room hight is also 2,50 not 4,50 as I mentioned above.
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Re: JBL 308P and 708P

Post by jajo »

Defender wrote: 2022-02-11 14:43I dont question the ability of the Tundra Monos together with the 3677 but your setup of the JBLs 308 looked like they are positioned too high.
Regardless how you position them, 3677 has physical qualities that 308/708 cannot match. When it comes to making music sound like it is a real orchestra playing in the livingroom. How we balance different qualities when making our speaker decision is very individual - not quite as black and white as when we select electronics.

I personally love the big sound of the cinema JBL speakers. If I had room for them and didn't have neighbours it would be tempted to replace 708P with 4675C.
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Re: JBL 308P and 708P

Post by Defender »

if the JBL 3677 is 100% in this capability how far away is the 708 from the 100% and how far are the 308 in your opinion?

and what does the compression driver in the 708 do better than the one in the 308?
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Re: JBL 308P and 708P

Post by matthias »

Defender wrote: 2022-02-12 18:12 if the JBL 3677 is 100% in this capability how far away is the 708 from the 100% and how far are the 308 in your opinion?

and what does the compression driver in the 708 do better than the one in the 308?
https://www.lejonklou.com/forum/viewtop ... 805#p61805

It is a long thread and sometimes going around circles.
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Re: JBL 308P and 708P

Post by jajo »

Defender wrote: 2022-02-12 18:12 if the JBL 3677 is 100% in this capability how far away is the 708 from the 100% and how far are the 308 in your opinion?

and what does the compression driver in the 708 do better than the one in the 308?
1) When it comes to big sound, 75%. Best of all regular sized speakers I've tried. Perfect compromise for someone like me that loves the big JBL sound but simply can't fit it both space-wise and neighbour-wise. When it comes to musicality and comfortable sound, the 708P crushes 3677, easily 125%.

Expect 75% to decrease as the room gets bigger. My music room is about 20 sq m.

2) The compression driver gives that bigger JBL sound, the feeling of being able to turn up the volume to the "big" scale without sounding compressed or distorted. This is further enhanced by stronger amps and a much better bass driver in 708P.
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