Use old HT equip for PC?

[dclapps]

I've got a few questions regarding my current audio setup.

I've got a 15 year old Sony amp that puts out "overall output: 135W (front, at rear/center off at 8 ohms)" for the front speakers, which is all I will be using. First, do I take that to mean RMS or peak? I've taken that info from the manual.

That is hooked up to two sony speakers (part of the original old system, but were the rears) that are rated 25W RMS. I am looking to upgrade my audio, but not sure if I want to keep this older amp and buy some passive axiom m3s/av123 elt525m, or ditch the amp and go with some active audioengine a5s. Any thoughts on the age of the amp negatively affecting the ability of the new monitors?

P.S. If the amp has a headphone out, but the manual only says "accepts low and high impedance headphones", does that mean it does not amplify headphones?

Thanks in advance,
Danny

 

[YOyoYOhowsDAjello]

Originally posted by: dclapps
I've got a few questions regarding my current audio setup.

I've got a 15 year old Sony amp that puts out "overall output: 135W (front, at rear/center off at 8 ohms)" for the front speakers, which is all I will be using. First, do I take that to mean RMS or peak? I've taken that info from the manual.

That is hooked up to two sony speakers (part of the original old system, but were the rears) that are rated 25W RMS. I am looking to upgrade my audio, but not sure if I want to keep this older amp and buy some passive axiom m3s/av123 elt525m, or ditch the amp and go with some active audioengine a5s. Any thoughts on the age of the amp negatively affecting the ability of the new monitors?

P.S. If the amp has a headphone out, but the manual only says "accepts low and high impedance headphones", does that mean it does not amplify headphones?

Thanks in advance,
Danny

For the power ratings, manufacturers have been very inconsistent with their ratings and what they mean. That might be a 1kHz RMS rating for a single channel driven or it might be something else.

Do you know the sensitivity rating on the Sony speakers you're using now? Do they get loud enough for you with the amp?

It doesn't take a whole lot of power to get decently loud with efficient speakers and a small listening distance. I'm using a sonic t-amp that only puts out about 6 watts before THD starts to rise dramatically (1% at 8 watts). That's driving some 87dB sensitivity speakers.

AV123 does have a package sale for ELT525Ms with a Tweak Audio City "Gizmo" for $299 as well. That's 25 watts into 4 ohms, not sure on the 8 ohm rating. The 525s are only 83dB for the sensitivity though...
http://av123.com/component/pag..._virtuemart/Itemid,37/

 

[dclapps]

I do not know the sensitivty as I cannot find a manual online for the speakers. As far as loudness, I have the amp connected to the computer and am forced to leave windows volume at 2 for somewhat loud sound. By volume 10 the neighbors are pissed. I know that THD on the amp is "less than 0.9% at 1kHz, 8ohms load", and you're right, that is with the rear and center off. You said "only 83dB".. what should I be looking at, given that I will use it for games and movies/music evenly?

Thanks again yoyo.

edit- the manual http://www.docs.sony.com/release/TAN721.PDF

 

[YOyoYOhowsDAjello]

Originally posted by: dclapps
I do not know the sensitivty as I cannot find a manual online for the speakers. As far as loudness, I have the amp connected to the computer and am forced to leave windows volume at 2 for somewhat loud sound. By volume 10 the neighbors are pissed. I know that THD on the amp is "less than 0.9% at 1kHz, 8ohms load", and you're right, that is with the rear and center off. You said "only 83dB".. what should I be looking at, given that I will use it for games and movies/music evenly?

Thanks again yoyo.

So the Sony amp is just an amp? (As opposed to a receiver / integrated amp with volume control)?

The sensitivity rating gives you a measure of how loud it will be 1 meter away from you if you feed it 1 watt. Doubling the wattage of your amp will give you 3dB more output.

You can play around with how different variables affect your output at the listening position here.
http://myhometheater.homestead.com/splcalculator.html

What sensitivity and amplifier power you'd need is going to be based on your own listening preferences. In my setup at the office with my t-amp and 87dB sensitivity speakers, I could potentially get 100dB out of it sending 5 watts to the speakers. I'm definitely not going to have it up loud enough to get 100dB peaks going in the office

I would do fine with 83dB speakers as well in my space, but I would need about 3x the amp output to match 100.8 dB output (13 watts).

Most of the time, you're going to be using less than 1 watt of power from your amp. If your existing amp is driving your existing speakers fine already (and has headroom to go louder than you would actually listen to it without significant distortion), then you're probably fine.

If you were trying to fill a large room, I would be more concerned about 83dB sensitivity speakers since your distance away from the speakers is going to make a big difference in output at the listening position. A desktop computer setup is where getting decent volume is going to be the easiest. I'm assuming your speakers will end up 3 feet or less away from you? At this distance, it's going to be quite easy to get good volume even with relatively low sensitivity speakers and medium to low amp power.

Do you have a model number for the speakers or amp? Maybe we can find something else about them.

 

[dclapps]

http://www.docs.sony.com/release/TAN721.PDF

That is the Sony amp, TA-N721. The Receiver in that diagram, I own as well. The speakers that I use, which used to be the rears of the original 5.0 system are SS-U41. I also have a center speaker, SS-CN72, but that is not hooked up, just like the receiver is not hooked up.

I do believe it is a power amp. The manual says so, as well as it does not have volume control. It has a unique cable, meant for connection to the receiver, as seen in the manual I linked to.

I am still grasping the ideas of how this all works: if we take the axiom m3 for example, with an SPL in room 1W/1M at 92dB, pair it with my 135W rms amp, I get roughly 117.1 dB SPL in my listening position. Should I be using the SPL Anechoic 1w/1m @ 88dB value instead (that gives me 113dB)? Having no idea of relativity between xxdB and perceived loudness, I have to assume (based on your 100dB office statement) that it is quite loud.

Am I going wrong somewhere? I, naively it seems, matched output watts of amp to input watts of speaker, never knowing until a week or so ago that a speaker spends its most time at 1W.

 

[YOyoYOhowsDAjello]

Originally posted by: dclapps
http://www.docs.sony.com/release/TAN721.PDF

That is the Sony amp, TA-N721. The Receiver in that diagram, I own as well. The speakers that I use, which used to be the rears of the original 5.0 system are SS-U41. I also have a center speaker, SS-CN72, but that is not hooked up, just like the receiver is not hooked up.

I do believe it is a power amp. The manual says so, as well as it does not have volume control. It has a unique cable, meant for connection to the receiver, as seen in the manual I linked to.

Based on those amp specs, you should have absolutely no problem with connecting virtually any 8-ohm speakers to that. I'm sure you're aware of this, but you can hook up the receiver unit between the computer and the amp to get volume controls.

Even though you don't have a subwoofer pre-out on your equipment, you could potentially hook up a subwoofer as well if you get one with high level inputs on it. One of the things that tends to be lacking in small speakers is the bass output, which can be a significant issue depending on your source material.

 

[YOyoYOhowsDAjello]

Originally posted by: dclapps
I am still grasping the ideas of how this all works: if we take the axiom m3 for example, with an SPL in room 1W/1M at 92dB, pair it with my 135W rms amp, I get roughly 117.1 dB SPL in my listening position. Should I be using the SPL Anechoic 1w/1m @ 88dB value instead (that gives me 113dB)? Having no idea of relativity between xxdB and perceived loudness, I have to assume (based on your 100dB office statement) that it is quite loud.

Am I going wrong somewhere? I, naively it seems, matched output watts of amp to input watts of speaker, never knowing until a week or so ago that a speaker spends its most time at 1W.

Anechoic is a more standard way to do it since room effects are based on the size and layout of the specific room.

To get an idea of what these dB measurements mean, you can find a lot of charts online for comparison to common events. Example:
http://www.jimprice.com/prosound/db.htm
I tend to listen to music at the 65dB-75dB range at home, and maybe 50 dB at work? I'm not sure about work, I've never measured it and my SPL meter doesn't go down that low. If I were the kind of guy who "rocked out", I might turn it up to 90dB for music.
With Action Movies, I would listen with peaks in the 100dB range but the sustained average volume overall would be significantly lower.

There's the issue of sustained vs. peak values as well. Not only are SPL levels of 90dB or greater very loud, but it can be dangerous.

OSHA has some guidelines for workplace safety on sustained SPL level exposure:

"Here is a typical breakdown of OSHA guidelines for maximum time exposure for potential hearing loss and/or permanent damage. (Regulation # 1910.95 - Occupational Noise Exposure)

90 dB SPL - 8 hours
95 dB SPL - 4 hours
100 dB SPL - 2 hours
105 dB SPL - 1 hour
110 dB SPL - 30 mins.
115 dB SPL - 15 mins.
115 dB and higher - 0 mins. - (Pain Threshold) - In other words, instant permanent hearing damage."

http://www.osha.gov/dts/osta/o...se/standards_more.html

dB is a logarithmic scale, so 100dB is 10 time more intense than 90dB for example. 110dB is 100 times more intense than 90dB.

Based on your amplifier power and the distance of your listening position, you will have no problem getting it extremely loud.

The wattage ratings on speakers are an indication of how much the speaker can take before it will be damaged. For example, if you sent 1000 watts through your speakers you have now, they might melt, or start on fire, or something.
The amplifier wattage rating (at least if it's honest) tells you how much clean power it will output before it starts clipping.
http://en.wikipedia.org/wiki/Clipping_(audio)
When it starts to clip, the signal is distorted and could potentially damage your speakers (especially tweeters).

It's better to have too much clean amplifier power than too little. There's more danger in having low amplifier power causing clipping than there is danger from sending too much clean power than speakers can handle. As you can tell by the SPL calculator tool, you can get very high SPL with relatively low amplifier power in most cases.

What you don't want to happen is that you set your amp's volume up so high that it can't supply enough power and it clips.

 

[dclapps]

First, thanks for the replies, if I haven't said so yet.

I chose not to based on space on my desk, but I might move the amp to under the desk so I could introduce the receiver. Other than volume control, is there any added benefit, assuming I do not use the other output/inputs or Sony EQ (which I also own)?

 

[YOyoYOhowsDAjello]

Originally posted by: dclapps
First, thanks for the replies, if I haven't said so yet.

I chose not to based on space on my desk, but I might move the amp to under the desk so I could introduce the receiver. Other than volume control, is there any added benefit, assuming I do not use the other output/inputs or Sony EQ (which I also own)?

The Equalizer and additional inputs would be the first two additional things that come to my mind as benefits as well.

(I added a little info about my listening levels in the previous post as well)

 

[dclapps]

I just caught that. Yoyo, I really appreciate your time and help, as always.

WRT to the equalizer, isn't the goal to get untouched sound?

 

[YOyoYOhowsDAjello]

Originally posted by: dclapps
I just caught that. Yoyo, I really appreciate your time and help, as always.

WRT to the equalizer, isn't the goal to get untouched sound?

An equalizer could be used in a couple different ways.

If your goal is to have your speakers play back the material as intended, an equalizer could potentially help you achieve a flat response from your speakers if the speakers themselves or the room they're in creates an uneven fequency response.

On the other hand, an equalizer could be used to just change things until you have them how it sounds best to you (bass boost, more high frequency output, whatever).

So depending on your intended purpose, you could use the equalizer to make your speaker's response flatter or shaped to how you want it.

Many modern receivers have advanced calibration setups with equalization in the digital domain. The equalization setup is controlled by the receiver according to the signal it gets from the input microphone. A few years ago, these kind of microphone setups were mainly for level matching and distance settings, but the latest generations have some very impressive equalization features as well. The goal in these systems is to get the speakers behaving nicely in your room. If they perform as expected, you'll get closer to the intended playback sound.

If you wanted to use your equalizer in a similar way, you'd have to get some sort of measurement tool to determine what kind of sound you're getting from your existing system and them compensate with the equalizer to flatten it out.

EDIT: I should let you know that my current equipment does not have equalization built into it. I plan to eventually get an external equalizer for my subwoofers and whatever pre-pro I buy next will have speaker calibration and equalization as a feature.