JBL 705i/708i (7 Series Master Reference Monitors) & 725G/728G (subwoofers): Jan 2015 - Page 53 - AVS Forum | Home Theater Discussions And Reviews
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post #1561 of 2918 Old 02-22-2017, 08:24 PM
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Originally Posted by McLuvin View Post
Yes, they are really good considering their price point. But I knew it could get better. So nice to see these made the day of light.
305s replaced Maggie 1.7i for me. I'll be waiting in line for the 705p. I'd expect there to be some differences attributed to CD vs. dome tweeter, front firing port vs. rear firing port, and overall better resonance free build quality. However, I think a night and day difference expectation might be unreasonable considering the basic physics involved.

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post #1562 of 2918 Old 02-22-2017, 09:13 PM
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Does anyone know if the baffle/waveguide of the 708i is just screwed on? I recall seeing internal shots that had what looked like baffle screws, but can't find them now.

I have an idea...

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post #1563 of 2918 Old 02-23-2017, 05:04 AM
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Here's the 705 internal from Sean Olive. It seems like it would just be the same for the 708, just scaled up. I wouldn't be surprised if they still used the same amount (6-8) of baffle screws:


Were you thinking about adding mass to the baffle? Noaudiophile tried it with the 308's. I don't think it had the intended effect.
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post #1564 of 2918 Old 02-23-2017, 03:20 PM
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Quote:
Originally Posted by 12B4A View Post
305s replaced Maggie 1.7i for me. I'll be waiting in line for the 705p. I'd expect there to be some differences attributed to CD vs. dome tweeter, front firing port vs. rear firing port, and overall better resonance free build quality. However, I think a night and day difference expectation might be unreasonable considering the basic physics involved.
It's the sound of a compression driver I was missing in the 308's. That and a little more output and they would have been perfect. Well, now we have the 708p's....

Interesting though is the max spl on the 708i and p. I ran them through the SPL calculator and it says the sensitivity on these are around 87db with the amp wattage rating for the 708p. I know that can't be right because the 308's come in around 92db sensitivity and the two are only 2db apart in total output. I know it's not all about output but those numbers just seem off. Anybody know what's going on here?
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post #1565 of 2918 Old 02-23-2017, 05:14 PM
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Quote:
Originally Posted by 12B4A View Post
Here's the 705 internal from Sean Olive. It seems like it would just be the same for the 708, just scaled up. I wouldn't be surprised if they still used the same amount (6-8) of baffle screws:





Were you thinking about adding mass to the baffle? Noaudiophile tried it with the 308's. I don't think it had the intended effect.


No, I assume structurally they're fine. I'm thinking of wrapping them in a prettier cabinet. The M2 waveguide is available but just too big.

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post #1566 of 2918 Old 02-24-2017, 06:59 PM
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Originally Posted by Gooddoc View Post
This is mounted

Hi. What's the length of that "rod"?
Is there any mounting holes on the back of the 708?
Do that holes on the Peavey VM70 mount align with those on the 708?
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post #1567 of 2918 Old 02-24-2017, 10:45 PM
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Originally Posted by Skylinestar View Post
What's the length of that "rod"?
Ah, I can't count how many times I've been asked that very question .

When I find my tape measurer I'll let you know.

There are top, bottom, and back mounting points on the 708 and the Peavey pattern fits if I recall correctly. If not, I drilled them .
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post #1568 of 2918 Old 02-25-2017, 10:42 AM
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Originally Posted by Gooddoc View Post
Ah, I can't count how many times I've been asked that very question .
Not to TOTALLY derail this conversation, but I got my usual e-mail notification of a post in this thread, with this the only text in the body of the email:

"This is mounted."

"What's the length of that "rod"?

A did a little double take there

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post #1569 of 2918 Old 02-25-2017, 10:46 AM
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Talking

I don't know, had my wife take a look and she said it was 6" from the base to the mounting point. But personally I think its a lot longer! Time to get out the ruler...
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post #1570 of 2918 Old 02-25-2017, 10:48 AM
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Originally Posted by Ted C View Post
I don't know, had my wife take a look and she said it was 6" from the base to the mounting point. But personally I think its a lot longer! Time to get out the ruler...
It always looks longer to the guys
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post #1571 of 2918 Old 02-25-2017, 10:50 AM
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Quote:
Originally Posted by skylinestar View Post
hi. What's the length of that "rod"?
6 1/2"
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post #1572 of 2918 Old 02-25-2017, 10:51 AM
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Yes indeed! But I guess what is most important is that you can hear the results of your mounting job when all is said and done
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post #1573 of 2918 Old 02-25-2017, 01:50 PM
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Yes indeed! But I guess what is most important is that you can hear the results of your mounting job when all is said and done
How's progress moving along on your room Ted??
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post #1574 of 2918 Old 02-25-2017, 05:44 PM
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Quick question. Usually with clip/limiter lights, if the light occasionally flickers, you're at the limit and you shouldn't increase the level at all, if anything back off a little. I'm guessing the same applies with the DCi 4/300 with the 708i's. I went to check the DCi amp out of curiosity while watching a concert blu ray tonight and noticed the red clip lights flickering occasionally during peaks. The 708i's are being used as surround channels currently and crossed at 80Hz.
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post #1575 of 2918 Old 02-25-2017, 07:09 PM
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lol, could have sworn I mentioned something about that...
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post #1576 of 2918 Old 02-25-2017, 07:23 PM
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Alternatively, it could be clipping at the input since the clipping indicator does come on in either output or input clipping. My $1 is on input clipping.

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post #1577 of 2918 Old 02-25-2017, 07:47 PM
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Originally Posted by 12B4A View Post
Alternatively, it could be clipping at the input since the clipping indicator does come on in either output or input clipping. My $1 is on input clipping.
You think he's clipping the input of the amp? That seems unlikely
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post #1578 of 2918 Old 02-25-2017, 07:59 PM
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I don't think it's the input on the amp. I was at -7 on the front of the AVM60. Wasn't even close to clipping on the Cats. I know the DCi 4/300 amp has limiter set in the DSP settings for the 708i's as @notnyt pointed out before. I'm assuming the lights flickering is just the limiters doing their job and protecting the speakers based on what the DSP settings set the limiters to for the 708i's. I was just posting here to make sure. It was loud, but it didn't seem THAT loud surrounds to be hitting their limits.
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post #1579 of 2918 Old 02-25-2017, 08:01 PM
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Originally Posted by Blackdevil77 View Post
I don't think it's the input on the amp. I was at -7 on the front of the AVM60. Wasn't even close to clipping on the Cats. I know the DCi 4/300 amp has limiter set in the DSP settings for the 708i's as @notnyt pointed out before. I'm assuming the lights flickering is just the limiters doing their job and protecting the speakers based on what the DSP settings set the limiters to for the 708i's. I was just posting here to make sure. It was loud, but it didn't seem THAT loud surrounds to be hitting their limits.
It'll compress the lower frequencies to prevent damage to the speakers. If it's just coming on briefly, I wouldn't worry.
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post #1580 of 2918 Old 02-26-2017, 12:00 AM
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Originally Posted by Blackdevil77 View Post
I don't think it's the input on the amp. I was at -7 on the front of the AVM60. Wasn't even close to clipping on the Cats. I know the DCi 4/300 amp has limiter set in the DSP settings for the 708i's as @notnyt pointed out before. I'm assuming the lights flickering is just the limiters doing their job and protecting the speakers based on what the DSP settings set the limiters to for the 708i's. I was just posting here to make sure. It was loud, but it didn't seem THAT loud surrounds to be hitting their limits.
Try adjusting the input gain on the amp from 32db to 29db. Setting is 's under "Input Configuration" in Audio Architect. You will need to adjust gain settings in the processor relative to the main speakers after your do.
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post #1581 of 2918 Old 02-26-2017, 12:14 AM
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Try adjusting the input gain on the amp from 32db to 29db. Setting is 's under "Input Configuration" in Audio Architect. You will need to adjust gain settings in the processor relative to the main speakers after your do.
This seems pointless as it would cause the input signal to the amp to be higher, and the output signal after adjusting the processor would remain unchanged. What benefit were you trying to go for here?
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post #1582 of 2918 Old 02-26-2017, 12:17 AM
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Originally Posted by notnyt View Post
This seems pointless as it would cause the input signal to the amp to be higher, and the output signal after adjusting the processor would remain unchanged. What benefit were you trying to go for here?
I assumed there may be some type of input gain mismatch between the 708 and the amp. Perhaps not if you think that will not have an affect (or make it worse).
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post #1583 of 2918 Old 02-26-2017, 12:38 AM
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Originally Posted by adidino View Post
I assumed there may be some type of input gain mismatch between the 708 and the amp. Perhaps not if you think that will not have an affect (or make it worse).
If he was clipping the input on the amp you'd want to raise the amp's gain so the input signal to it could be lowered.

As these amps are rated at +20dBu before compression, and +26 before clipping, it's not likely he's clipping the inputs.

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Maximum Input Level before Compression +20 dBu
Maximum Input Level before Clipping +26 dBu
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post #1584 of 2918 Old 02-26-2017, 01:04 AM
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Originally Posted by Blackdevil77 View Post
I don't think it's the input on the amp. I was at -7 on the front of the AVM60. Wasn't even close to clipping on the Cats. I know the DCi 4/300 amp has limiter set in the DSP settings for the 708i's as @notnyt pointed out before. I'm assuming the lights flickering is just the limiters doing their job and protecting the speakers based on what the DSP settings set the limiters to for the 708i's. I was just posting here to make sure. It was loud, but it didn't seem THAT loud surrounds to be hitting their limits.
The clip light can also flash if the TLC protection circuit is engaging. As I said, the only way to know for sure what is going on is to monitor the input/output signals in Audio Architect. Otherwise you're just guessing.
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post #1585 of 2918 Old 02-26-2017, 06:46 AM
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I wasn't clipping the input. After some thinking, I think I know what it is. I'm a little embarrassed to say what I did.... or didn't do for that matter that may solve the problem.
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post #1586 of 2918 Old 02-26-2017, 02:08 PM
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Originally Posted by Molon_Labe View Post
You realized you bought a speaker too small for the output?

I kid...I kid.

Glad you got it sorted out.
Lol these speakers don't have the same output the Sparks have, but they do have more than what I experienced last night. Used the wrong ARC profile and had the surrounds running 5db and 6db hot.
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post #1587 of 2918 Old 02-26-2017, 09:12 PM
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Lol these speakers don't have the same output the Sparks have, but they do have more than what I experienced last night. Used the wrong ARC profile and had the surrounds running 5db and 6db hot.
The Spark is a single 8" design, no? I doubt that it has greater output, particularly if the 708 is run active like the spark.
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post #1588 of 2918 Old 02-26-2017, 10:35 PM
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Originally Posted by Gooddoc View Post
The Spark is a single 8" design, no? I doubt that it has greater output, particularly if the 708 is run active like the spark.
708 is low sensitivity and setup to play to lower frequencies. it gives up output for extension. jbl limits the power on the low end to 250 watts, hence why owners are seeing clipping below reference levels. it's not hard to best them in output capabilities. The Sparks are designed to be run with a sub, not as a monitor, so they can get away with a higher sensitivity driver.

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post #1589 of 2918 Old 02-27-2017, 01:45 AM
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Originally Posted by notnyt View Post
708 is low sensitivity and setup to play to lower frequencies. it gives up output for extension. jbl limits the power on the low end to 250 watts, hence why owners are seeing clipping below reference levels. it's not hard to best them in output capabilities. The Sparks are designed to be run with a sub, not as a monitor, so they can get away with a higher sensitivity driver.
Owners? Aside from the "owner" that reported it, and then realized why, who else?

In pretty much any residential surround application, the 7's run active and crossed over at anything over 70 Hz are not going to clip.
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post #1590 of 2918 Old 02-27-2017, 01:50 AM
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Originally Posted by Gooddoc View Post
Owners? Aside from the "owner" that reported it, and then realized why, who else?
likely anyone else who tries to play them at reference with jbl factory settings and and is further than 3 feet from them?

5db hot but -7 mv is 2db under reference, and it was still hitting the clip indicator.
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