Pre-amp output signal booster?

Pogre

Pogre

Audioholic Overlord
Yep. We’ve all seen these before!!!

Then try explaining to the happy new owner why it really doesn’t work like that
But it says so on the box?!?!?!?!
I'll eat my shorts if it produces more than 50 watts of clean power to any speaker, lol.
 
Verdinut

Verdinut

Audioholic Ninja
Right?!?! I hate that they print that shitt on the box.
Governments could enforce laws to fine companies with false claims for their products, but that entails more employees with the added costs..

For instance, the FTC used to control power amplifier specs, but that was abandoned years ago, with the result that manufacturers can claim almost anything they want for their products. One example of course is misleading inflated power ratings as they were recently advertised with some AVRs.
 
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M

McChris

Enthusiast
Yeah... internets and fluffy, subjective reviews... pft. Unfortunately there's a lot of woo and magical thinking in this hobby so you gotta be careful and take a lot of it with a grain of salt. Objective measurements and accurate specs will tell you much more.

Bigger speakers in general will have the ability to get louder with less power, but isn't always the case. Sensitivity specs are what's meaningful here. It's a lot more efficient to get higher sensitivity speakers than to throw gobs of power at them. A speaker that's 3 dB more sensitive (say 91 dB compared to 88 dB, both common specs for speakers) is equivalent to doubling your amp power (or more accurately, halving the power requirement to reach the same volume). After that the ability to handle a lot of power is what's relevant for overall speaker wind in your hair volumes.

*Edit: having a more powerful external amp can still provide some benefits. Like you mention it will take some heat off your receiver, and when you do upgrade your speakers you'll have plenty of power for them to play plenty loud.
TBH, I've never heard of speaker sensitivity before, or never paid attention to it if I did. That's crazy 3dB makes that much difference. Especially when the scale is between 91 and 88. Must be some of that logarithmic math junk.

Def going to keep this in mind as I look for new towers. Thank you
 
Pogre

Pogre

Audioholic Overlord
TBH, I've never heard of speaker sensitivity before, or never paid attention to it if I did. That's crazy 3dB makes that much difference. Especially when the scale is between 91 and 88. Must be some of that logarithmic math junk.

Def going to keep this in mind as I look for new towers. Thank you
Yup, logarithmic. No matter where you start, it takes double the power to gain 3 db. It's something like 10x power for a perceived doubling of loudness. Did you play around with that calculator HD linked earlier? It's not the holy grail for predicting every speaker because it doesn't account for resistance, but it does give you an idea of the relation between power, volume and distance. Plus there's a little chart that gives a few examples of how loud something is at a given spl range.

 
M

McChris

Enthusiast
And you're learning that pro gear shouldn't mix with consumer gear. If people refuse to learn about what an amplifier needs WRT input voltage, impedance matching, etc, they'll never be satisfied after being convinced that what they need is something that isn't designed to work with what they have.

RTFM is an acronym that needs to be heeded and if you were to read the manual before buying AND understand it, you wouldn't be having this problem.

A properly matched preamp, power amp and speakers, chosen to achieve the output needed for the application, will produce the desired results. Guesswork will result in poor performance unless the guesses are informed or lucky. Power amplifiers need a certain voltage in order to achieve full output power, but it's not just voltage, its input impedance needs to be a decent match to the output impedance and voltage of whatever feeds it the signal.

"Line level converter"? Is that something you might connect to the Marantz' speaker terminals and convert to line level, like the ones used for a car stereo? You won't find one that properly handles the power output of 100W @8 Ohms.

You really should learn about the technical side of audio- it would save a lot of time, money and frustration. The output from the Crown isn't going to double the output level from the Marantz. I also don't think your speakers are going to be very happy if you hit them with the full output from the Crown for any length of time since they're rated for 200W.

How loud do you want the system to be?
I want it loud enough that I go "damn!" and kinda wince backwards as I try to find the volume down button.

Not really though, that's my inner teenager speaking. But something between that and a system that is completely soundless when there's a pause in the music, but so much power that when the first guitar string is plucked, it hits you in the face and makes your arm hairs stand up.

I'll be the first to admit I lack sufficient knowledge with this stuff. And in this case, TFM for the Crown didn't help. I've wired up countless car stereos when I was a kid, so I learned a lot of bad habits.

Here's what I grew up with:
More speakers = louder
Bigger speakers = louder + bass
Bigger amp = way louder
and then all the other junk, like dropping your subs to 1 ohm, catching your amp on fire because it's not 1 ohm capable, using 12v power capacitors to save your alternator, the big 3 wiring, etc
 
M

McChris

Enthusiast
I want it loud enough that I go "damn!" and kinda wince backwards as I try to find the volume down button.

Not really though, that's my inner teenager speaking. But something between that and a system that is completely soundless when there's a pause in the music, but so much power that when the first guitar string is plucked, it hits you in the face and makes your arm hairs stand up.

I'll be the first to admit I lack sufficient knowledge with this stuff. And in this case, TFM for the Crown didn't help. I've wired up countless car stereos when I was a kid, so I learned a lot of bad habits.

Here's what I grew up with:
More speakers = louder
Bigger speakers = louder + bass
Bigger amp = way louder
and then all the other junk, like dropping your subs to 1 ohm, catching your amp on fire because it's not 1 ohm capable, using 12v power capacitors to save your alternator, the big 3 wiring, etc
And this was before the internet, so you went by what your friends told you.
It was before books too, I think
 
lovinthehd

lovinthehd

Audioholic Jedi
Must be some of that logarithmic math junk.
Indeed. Lots of audio/electronics is this way....

That comment's signature worthy, tho...

Sounds like you might like more dynamic speakers. Maybe even self powered/active ones so you don't have to screw around with amps (but still use the pre-outs on your current avr).
 
Pogre

Pogre

Audioholic Overlord
I want it loud enough that I go "damn!" and kinda wince backwards as I try to find the volume down button.

Not really though, that's my inner teenager speaking. But something between that and a system that is completely soundless when there's a pause in the music, but so much power that when the first guitar string is plucked, it hits you in the face and makes your arm hairs stand up.

I'll be the first to admit I lack sufficient knowledge with this stuff. And in this case, TFM for the Crown didn't help. I've wired up countless car stereos when I was a kid, so I learned a lot of bad habits.

Here's what I grew up with:
More speakers = louder
Bigger speakers = louder + bass
Bigger amp = way louder
and then all the other junk, like dropping your subs to 1 ohm, catching your amp on fire because it's not 1 ohm capable, using 12v power capacitors to save your alternator, the big 3 wiring, etc
Just to expand a little bit, how they get that sensitivity spec is how loud a speaker can get with 1 watt of power at 1 meter. That's how a lot of manufacturers spec them, but the more accurate way to do it is to use 2.83 v, which takes impedance into account (as I understand it).

Big powerful amps don't hurt to have, and paired with high power handling sensitive speakers can get plenty loud, but speakers are definitely the biggest factor in the equation. That and room acoustics. So, how are you sitting for subwoofage?
 
Verdinut

Verdinut

Audioholic Ninja
Just to expand a little bit, how they get that sensitivity spec is how loud a speaker can get with 1 watt of power at 1 meter. That's how a lot of manufacturers spec them, but the more accurate way to do it is to use 2.83 v, which takes impedance into account (as I understand it).

Big powerful amps don't hurt to have, and paired with high power handling sensitive speakers can get plenty loud, but speakers are definitely the biggest factor in the equation. That and room acoustics. So, how are you sitting for subwoofage?
Now, the figure used by most manufacturers and reviewers for a loudspeaker sensitivity is based on an input of 2.83 volts at 1 meter. So an 8 ohm driver will draw 1 watt from an amplifier while the 4 ohm one would draw 2 watts for a 3db louder output.
 
M

McChris

Enthusiast
I've been taking all of your advice and I think it's dialing in!
I'm going to keep at this for a bit and I'll come back later with results.

"Lowering the gain" on my expectations has been paramount, I think.
But nobody told me step 1 was "take shot, crack beer".
;D
 
M

McChris

Enthusiast
Oh, and to give more insight, here's what I'm working with:
Marantz SR5008
Crown XLi (powering front)
Polk monitor series II 60's (front)
Polk CS1 (center)
Polk S15's (surround)
Polk RM1300's (front height)
Klipsch R-125SW (powered sub)


*pics are a few months old, not all equipment
 

Attachments

lovinthehd

lovinthehd

Audioholic Jedi
I'd rather have those L/R speakers spread out a bit more.

How did you determine best location of the sub?

ps the couch up against the back wall isn't doing you any favors acoustically either
 
M

McChris

Enthusiast
Alright, first off - thanks to everyone for your input. You've helped me gauge my understanding. I'm not embarrassed to admit I don't know much about this stuff. In fact, I enjoy learning, in everything I do.

As a recap, I had a Pioneer vsx-521, Klipsch sub, and a bunch of Polk speakers. Not bad sounding , but after reading some "extreme audiophile" comments somewhere, I determined I needed more.

I got upgraditis and bought a pro power amp. I had looked around for a few weeks, then pulled the trigger on a Crown XLi1500 based on the Amazon reviews. The pioneer didn't have preouts, so I upgraded my receiver at the same time (the Marantz).

Naturally, I was getting excited as all this poop was coming in. Days felt like weeks, I couldn't wait.

When it all arrived, I requested the day off from work. I think my co-workers were excited too - not about the stereo, but that they didn't have to hear about it anymore.

So, after I hooked it all up, I was very unimpressed. I can see now that my expectations weren't inline with reality.

But!... after messing with more settings, changing some cables out, and adjusting the EQ on my Macbook, I'm happy with where I'm at.

I had it sounding pretty good with the Crown pushing the Polks, then I removed the Crown to see how much difference it made.

It sounds just as good without it.

The Crown only added a slight increase in discernible "umpf", or machismo.
Not $400 worth of "umpf" though.
I'm returning it.

But like I said, I've got it sounding pretty decent now.
I've got to catch up on some replies from above (probably tomorrow) but wanted to update where I'm at.

Thanks again,
I'll be back with more questions!
 
highfigh

highfigh

Audioholic Slumlord
I want it loud enough that I go "damn!" and kinda wince backwards as I try to find the volume down button.

Not really though, that's my inner teenager speaking. But something between that and a system that is completely soundless when there's a pause in the music, but so much power that when the first guitar string is plucked, it hits you in the face and makes your arm hairs stand up.

I'll be the first to admit I lack sufficient knowledge with this stuff. And in this case, TFM for the Crown didn't help. I've wired up countless car stereos when I was a kid, so I learned a lot of bad habits.

Here's what I grew up with:
More speakers = louder
Bigger speakers = louder + bass
Bigger amp = way louder
and then all the other junk, like dropping your subs to 1 ohm, catching your amp on fire because it's not 1 ohm capable, using 12v power capacitors to save your alternator, the big 3 wiring, etc
TFM for the Crown IS almost useless but because they typically design and sell for the pro/commercial market, they're assuming some level of technical knowledge, so they leave out info that would be 'common knowledge' in the industries. How consumers interpret it isn't really at the top of their list of requirements. Also, the specs page shows 'Recommended for portable PA'.

Here's an example of the technical specs for a JBL speaker, which might be used with this type of amplifier- as you can see, it contains info that could be considered 'gibberish' to many people, but can be used in a quick review by someone who uses it for design purposes on a regular basis-


The next link has some additional info including "Voltage Gain- 31dB", which is what I was referring to when I mentioned that amplifier gain is fixed- the level controls are for achieving the needed output and noise levels, so max output would be reached at full rotation of the controls, but ONLY if the input level is .775V or 1.4V- sending more input voltage at either setting will result in more distortion, less headroom and will negatively affect the sound quality.


WRT "what you grew up with:

- More speakers=more sound, but only if the amplifier can handle the load. If not, more amplifiers are needed
- Bigger speakers=louder+more bass: not necessarily, if the speakers are less sensitive and are tuned to a higher frequency. Plenty of big speakers are almost useless for true low frequencies and they need to be in the correctly designed enclosure.
- Bigger amp=way louder: because we don't hear specific increases of power (double, triple, etc) as twice or three times as loud, you could increase the power output by 4 times and not hear it as 4 times as loud- to make it sound twice as loud, ten times as much power is needed and if the speakers can't handle it, they turn into smokey bits.
- "...using 12V power capacitors to save your alternator...": that only prevents voltage sag when the power amp(s) are cranking and the alternator can't maintain constant voltage. An alternator that can't handle more current will die early but another problem is the voltage regulator and the rectifier- often, alternator noise (AC ripple) can be seen if an oscilloscope is connected to the alternator's output post.

The car audio world is very different from the home/pro/commercial audio world in many ways but really, it's basically the same once you move past the power supply. However, the room vs the interior of a vehicle is another area where this is totally different- a vehicle is a confined small space and room size can vary greatly.
 
highfigh

highfigh

Audioholic Slumlord
Yep. We’ve all seen these before!!!

Then try explaining to the happy new owner why it really doesn’t work like that
But it says so on the box?!?!?!?!
Ever go to Beast Buy to look at receivers? The card on the shelf shows the power output by adding all channels, so what may be only 85W/channel with 7 channels, it would show close to 600W. Completely misleading and it needs to stop.

When I worked in car audio, we used to call wildly overstated power output 'Sony Watts', 'JBF' or 'WLS'. 'JBF' stands for 'Just Before Fire' and 'WLS' stands for 'When Lightning Strikes'.
 
highfigh

highfigh

Audioholic Slumlord
TBH, I've never heard of speaker sensitivity before, or never paid attention to it if I did. That's crazy 3dB makes that much difference. Especially when the scale is between 91 and 88. Must be some of that logarithmic math junk.

Def going to keep this in mind as I look for new towers. Thank you
Our hearing is on a logarithmic scale.

A 3dB decrease in sensitivity means that twice as much power is needed an that can make the difference between one speaker being useful in a system, or not. If the speaker can't handle the power needed to produce the output required by the application, it will be destroyed in a short time. This is the reason PA speaker sensitivity may be in the 103dB @ 2.83V when measured from one meter (standard voltage and distance), but the impedance must be considered because the old method showed 1Watt, which corresponds to 2.83V for an 8 Ohm driver, but not a 4 Ohm driver, which would need 2V to qualify as '1Watt'.

One of the good things about working with multiple power amps in a car- the input level on the amp and output level on EQ/DSP/active crossover can be adjusted to balance the levels of the different speakers, rather than choosing speakers because their sensitivity falls within a narrow range.
 
Pogre

Pogre

Audioholic Overlord
Alright, first off - thanks to everyone for your input. You've helped me gauge my understanding. I'm not embarrassed to admit I don't know much about this stuff. In fact, I enjoy learning, in everything I do.

As a recap, I had a Pioneer vsx-521, Klipsch sub, and a bunch of Polk speakers. Not bad sounding , but after reading some "extreme audiophile" comments somewhere, I determined I needed more.

I got upgraditis and bought a pro power amp. I had looked around for a few weeks, then pulled the trigger on a Crown XLi1500 based on the Amazon reviews. The pioneer didn't have preouts, so I upgraded my receiver at the same time (the Marantz).

Naturally, I was getting excited as all this poop was coming in. Days felt like weeks, I couldn't wait.

When it all arrived, I requested the day off from work. I think my co-workers were excited too - not about the stereo, but that they didn't have to hear about it anymore.

So, after I hooked it all up, I was very unimpressed. I can see now that my expectations weren't inline with reality.

But!... after messing with more settings, changing some cables out, and adjusting the EQ on my Macbook, I'm happy with where I'm at.

I had it sounding pretty good with the Crown pushing the Polks, then I removed the Crown to see how much difference it made.

It sounds just as good without it.

The Crown only added a slight increase in discernible "umpf", or machismo.
Not $400 worth of "umpf" though.
I'm returning it.

But like I said, I've got it sounding pretty decent now.
I've got to catch up on some replies from above (probably tomorrow) but wanted to update where I'm at.

Thanks again,
I'll be back with more questions!
Thanks for the update, and lemme just say it's refreshing to meet someone who's willing to hear the facts and approach this objectively. So many people can't get past expectation bias and will swear there's a "night and day" difference when there isn't. Almost every single time sighted bias and placebo has everything to do with those "improvements" and objectivity goes out the window.

You discovered on your own what we tell folks all the time here. Bigger amps don't always lead to better sound, and most of the time aren't the solution folks have been led to believe. Speakers and room acoustics are almost ALWAYS going to have the biggest impact. Hit us up when you're ready and we'll help you zero in on a pair that will hit your budget and performance goals (or at least try to get close! :p).

Also, don't underestimate good subwoofage. They're speakers too. A good sub or 2 can take some heat off your main speakers allowing them to play louder and cleaner while filling in the lowest frequencies, and good, clean bass can clean up the whole frequency range. It's more than just adding boom and thump.
 
lovinthehd

lovinthehd

Audioholic Jedi
I went thru what you did a long time ago, back in the old 2-ch only days, switched from a relatively good and powerful receiver to separates with a much more powerful amp (almost 4x more powerful)....and the expectations were fairly high. I was a bit disappointed in how little difference it made in actual use. It was very good, but wasn't living up to the hype I got from magazines and sales people. Of the four avrs I run, for my use none really need external amps, but had a few extra lying around so do use a couple on my main system in the biggest room just because I can more than it makes a big difference....

ps rather than sell it, that amp would make a good basis for a pair of diy subs
 
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