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post #1 of 23 Old 07-25-2012, 11:53 AM - Thread Starter
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I just want to ensure I'm not putting my new speakers in danger of being damaged.

I have 2 JBL Control 28's (professional grade contractor speakers) connected to my Pioner VSX-521K receiver. The receiver is rated at 110 watts per channel at 8 ohms. The 2 JBL speakers are rated at 175W continuous power at 8 ohms.

While the receiver is really designed for 5.1, I only have these 2 speakers connected. I don't hear any distortion or clipping. I'm just worried I might be doing long term damage -- not sure.

On a side note, I would really like a little more bass out of these. It may just be because they're underpowered a bit. They have 8" woofers so I figured they'd have considerable bass.
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post #2 of 23 Old 07-25-2012, 12:16 PM
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Quote:
Originally Posted by TheCulpster View Post

I have 2 JBL Control 28's (professional grade contractor speakers) connected to my
Pioner VSX-521K receiver. The receiver is rated at 110 watts per channel at 8 ohms.
The 2 JBL speakers are rated at 175W continuous power at 8 ohms.

A 100W/ch AVR is a reasonable match for 8-Ohm, 175W speakers.
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Originally Posted by TheCulpster View Post

I don't hear any distortion or clipping.

Sounds good. [pun almost unintentional]
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Originally Posted by TheCulpster View Post

I'm just worried I might be doing long term damage -- not sure.

No worries. Clipping is the big danger, not playing the speakers as they're intended to be played.
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post #3 of 23 Old 07-25-2012, 12:21 PM
 
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In reality, not too much bass in these as they're limited to 60Hz.

http://www.jblpro.com/pages/install/cc_surface.htm#28

http://www.jblpro.com/pub/install/control/JBL.Ctrl28.pdf

With your Amp. having a 110w capability and your speakers being rated 175w continuous, you'd have to work at destroying these speakers. If you want more bass, you'll need to consider adding a small 10" subwoofer.
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post #4 of 23 Old 07-25-2012, 12:41 PM
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Quote:
Originally Posted by TheCulpster View Post

I have 2 JBL Control 28's
While the receiver is really designed for 5.1, I only have these 2 speakers connected. I don't hear any distortion or clipping. I'm just worried I might be doing long term damage -- not sure.
On a side note, I would really like a little more bass out of these. It may just be because they're underpowered a bit. They have 8" woofers so I figured they'd have considerable bass.

The Speakers will let you know if something is wrong - the JBl is somewhat limited bass wise.
For one on a tight budget, the Energy S10.3 subwoofer is a nice one, and it will go down low.
http://www.newegg.com/Product/Product.aspx?Item=N82E16882269026

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post #5 of 23 Old 07-25-2012, 01:49 PM
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No, those speakers do not have any bass to speak of. You need a subwoofer.

The Klipsch RW12D sub is one that is fairly good and runs $300-400 or so if you shop around. That is the cheapest decent one I could recommend.

Your amplifier and speakers should be a good match; no problem there.



Quote:
Originally Posted by TheCulpster View Post

I just want to ensure I'm not putting my new speakers in danger of being damaged.
I have 2 JBL Control 28's (professional grade contractor speakers) connected to my Pioner VSX-521K receiver. The receiver is rated at 110 watts per channel at 8 ohms. The 2 JBL speakers are rated at 175W continuous power at 8 ohms.
While the receiver is really designed for 5.1, I only have these 2 speakers connected. I don't hear any distortion or clipping. I'm just worried I might be doing long term damage -- not sure.
On a side note, I would really like a little more bass out of these. It may just be because they're underpowered a bit. They have 8" woofers so I figured they'd have considerable bass.
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post #6 of 23 Old 07-25-2012, 04:28 PM - Thread Starter
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Originally Posted by commsysman View Post

No, those speakers do not have any bass to speak of. You need a subwoofer.
The Klipsch RW12D sub is one that is fairly good and runs $300-400 or so if you shop around. That is the cheapest decent one I could recommend.
Your amplifier and speakers should be a good match; no problem there.

Its decent but I figured they would have more being an 8" woofer. But, I'm no expert on speakers. I work at an amusement park and these are the speakers they have throughout the park. They really do sound great. I do hear that Klipsch makes pretty good subwoofers.
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post #7 of 23 Old 07-25-2012, 05:25 PM
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Its decent but I figured they would have more being an 8" woofer.
P.A. speakers are more about volume (and clarity), so a tradeoff is made & bass extension is the loser. They could design a PA speaker with volume AND extension but it would cost much more.

Another example of volume vs. extension: the Klipsch Heresy. It uses a 12" woofer and only reaches down to 58Hz but is extremely efficient - 99dB! - and in turn requires little power to reach very high volume levels.
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post #8 of 23 Old 07-25-2012, 07:23 PM
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Quote:
Originally Posted by TheCulpster View Post

Its decent but I figured they would have more being an 8" woofer.
The size of the woofer has no bearing on the frequency response. They don't go very low because they're not supposed to. Per JBL: The Control® 28 offers a rich sonic character making it a perfect choice for restaurants, health clubs, under balcony, outdoor theme & waterparks, or other applications where foreground/background music and paging are required. Those applications don't require deep bass extension. Moreover as they're intended for mounting in free-space the cab is tuned to give a boost at 100Hz, which reduces further their response below 80Hz than a speaker intended for indoor use exclusively.

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post #9 of 23 Old 07-25-2012, 07:26 PM
 
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Originally Posted by donutfan View Post

They could design a PA speaker with volume AND extension but it would cost much more.

Klipsch has already done what you suggest and yes, they cost more than the Heresy III's. Today's Klipsch RF-7 goes down to 30Hz with a 101dB sensitivity.

Specs for the RF-7:

FREQUENCY RESPONSE: 30Hz-24KHz ± 3dB

SENSITIVITY: 101dB @ 2.83V / 1m
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post #10 of 23 Old 07-25-2012, 07:52 PM
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Originally Posted by BeeMan458 View Post

Today's Klipsch RF-7 goes down to 30Hz with a 101dB sensitivity.
Specs for the RF-7:
FREQUENCY RESPONSE: 30Hz-24KHz ± 3dB
SENSITIVITY: 101dB @ 2.83V / 1m
Perhaps a bit OT, but that spec is not accurate. Bass reflex speakers aren't capable of that combination of sensitivity and LF extension.

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post #11 of 23 Old 07-25-2012, 09:01 PM
 
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Quote:
Originally Posted by Bill Fitzmaurice View Post

Perhaps a bit OT, but that spec is not accurate. Bass reflex speakers aren't capable of that combination of sensitivity and LF extension.

Do tell. So Klipsch is selling wolf tickets with that spec? confused.gif

In the meantime, most folks like me add a halfway decent sub and filter at 80Hz. Where is Klipsch going wrong with these specs?

The Epic, CF-3's mains in our system are spec'd at:

FREQUENCY RESPONSE: 35Hz-20kHz(+-)3dB

SENSITIVITY: 100dB @ 1watt/1meter

And today the mains were married up with a Klipsch RC-64 II which spec's out much higher at:

FREQUENCY RESPONSE: 59Hz-24KHz ± 3dB

SENSITIVITY: 99dB @ 2.83V / 1m

What's really happening here?

confused.gif

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post #12 of 23 Old 07-26-2012, 06:02 AM
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Originally Posted by BeeMan458 View Post

Do tell. So Klipsch is selling wolf tickets with that spec? Where is Klipsch going wrong with these specs?
Ask Klipsch for measured SPL charts, see what their response is. I know exactly what Paul Klipsch would have said if someone working for him made those claims for those speakers, it's a common expression that describes cow excrement. He would have followed that expression with the words "You're fired!".

Paul Klipsch backed up his frequency response and sensitivity claims with actual measured response charts for every speaker he made; he knew that published specs without charts aren't worth the paper they're printed on, and had the integrity to back up all of his claims with factual data. Where the Klipsch company is concerned that integrity seems to have died with him, and now Klipsch has descended to using BS (there's that term again) specs with no supporting data. Not that the current Klipsch management is alone in this regard, but they seem to be amongst the worst offenders where specsmanship is concerned.

The truth of the matter is that a dual woofer bass reflex design may be capable of 101dB sensitivity, or it may be capable of -3dB response to 30Hz, but it cannot do both. If it has 101dB sensitivity it may be -3dB to perhaps 60Hz, if it's -3dB at 30 Hz it may have perhaps 92dB sensitivity.

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post #13 of 23 Old 07-26-2012, 06:24 AM
 
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Quote:
Originally Posted by Bill Fitzmaurice View Post

I know exactly what Paul Klipsch would have said if someone working for him made those claims for those speakers, it's a common expression that describes cow excrement. He would have followed that expression with the words "You're fired!".

eek.gif

Then I guess I best make sure I only let sugar go down those wires.

eek.gif

Now, I have to make a phone call.




The best I have is anechoic chamber measures vs real life experience.

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post #14 of 23 Old 07-26-2012, 06:58 AM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

Ask Klipsch for measured SPL charts, see what their response is. I know exactly what Paul Klipsch would have said if someone working for him made those claims for those speakers, it's a common expression that describes cow excrement. He would have followed that expression with the words "You're fired!".
Paul Klipsch backed up his frequency response and sensitivity claims with actual measured response charts for every speaker he made; he knew that published specs without charts aren't worth the paper they're printed on, and had the integrity to back up all of his claims with factual data. Where the Klipsch company is concerned that integrity seems to have died with him, and now Klipsch has descended to using BS (there's that term again) specs with no supporting data. Not that the current Klipsch management is alone in this regard, but they seem to be amongst the worst offenders where specsmanship is concerned.
The truth of the matter is that a dual woofer bass reflex design may be capable of 101dB sensitivity, or it may be capable of -3dB response to 30Hz, but it cannot do both. If it has 101dB sensitivity it may be -3dB to perhaps 60Hz, if it's -3dB at 30 Hz it may have perhaps 92dB sensitivity.

So the real question is, which is it with the speakers mentioned (are they that sensitive, or do they actually extend that low, or is it neither)? I have read several times now that Klipsch sensitivity ratings are overhyped, and your post makes complete sense why that is.

Honestly, unless it is 2 channel music I just don't expect my speakers to do much below 80hz. There are so many good inexpensive subwoofers out there that are made for output and extension and have their own dedicated amp, it seems pointless to try and use speakers to extend lower than 80hz for anything but 2 channel music.
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post #15 of 23 Old 07-26-2012, 09:20 AM
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So the real question is, which is it with the speakers mentioned (are they that sensitive, or do they actually extend that low, or is it neither)?
Measured SPL charts would reveal that. IME there are two reasons why manufacturers don't provide them: either they don't have any or they do and don't want you to see them.

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post #16 of 23 Old 07-26-2012, 10:04 AM
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Originally Posted by Bill Fitzmaurice View Post

Perhaps a bit OT, but that spec is not accurate. Bass reflex speakers aren't capable of that combination of sensitivity and LF extension.
Note that it is spec'ed to voltage and not 1 watt. Since the impedance dips way lower than 8 ohms, that can account for maybe 4 dB... How low would you expect it to be at 1W?

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post #17 of 23 Old 07-26-2012, 10:39 AM
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Note that it is spec'ed to voltage and not 1 watt. Since the impedance dips way lower than 8 ohms, that can account for maybe 4 dB... How low would you expect it to be at 1W?
Also impossible to say, as Klipsch rates them as '8 ohm compatible'. I hope that's not really 4 ohms, which certainly isn't. And even 4 ohms would only realize 3dB.

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post #18 of 23 Old 07-26-2012, 11:31 AM
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They have a known nasty low dip...

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post #19 of 23 Old 07-26-2012, 11:38 AM
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My klipsch speakers were rated at 97 dBs for sensitivity and they were spot on for my M&K speakers which were 92 dB's. So either the M&K's were 97 dBs or the Klipsch were 92 dBs. I am guessing the latter.
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post #20 of 23 Old 07-26-2012, 12:39 PM
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http://www.hometheater.com/content/klipsch-rb-81-speaker-system-ht-labs-measures

http://www.klipsch.com/rb-81-ii-bookshelf-speaker

Spec = 97dB
Measured = 91dB
Note both are at 2.83V

I believe the measurements. PWK would be ashamed.
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post #21 of 23 Old 07-26-2012, 03:12 PM
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Quote:
Originally Posted by TheCulpster View Post

I just want to ensure I'm not putting my new speakers in danger of being damaged.
I have 2 JBL Control 28's (professional grade contractor speakers) connected to my Pioner VSX-521K receiver. The receiver is rated at 110 watts per channel at 8 ohms. The 2 JBL speakers are rated at 175W continuous power at 8 ohms.
While the receiver is really designed for 5.1, I only have these 2 speakers connected. I don't hear any distortion or clipping. I'm just worried I might be doing long term damage -- not sure.
On a side note, I would really like a little more bass out of these. It may just be because they're underpowered a bit. They have 8" woofers so I figured they'd have considerable bass.

VSX-521K is rated 80w RMS. The 110w number is the "dynamic" power rating. In other words your Pioneer is underpower for your JBLs.

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post #22 of 23 Old 07-26-2012, 10:01 PM - Thread Starter
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Originally Posted by TuenMuner View Post

VSX-521K is rated 80w RMS. The 110w number is the "dynamic" power rating. In other words your Pioneer is underpower for your JBLs.

So do you think any damage could have been done? I heard no distortion or clipping. I'm not blasting them or anything.
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post #23 of 23 Old 07-27-2012, 05:00 AM
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So do you think any damage could have been done? I heard no distortion or clipping. I'm not blasting them or anything.
If it sounds good it is good. The only risk with running a low power amp is to your tweeters if the amp is driven to clipping, and the distortion that would result will serve as fair warning long before damage might result.

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