Is an amp necessary?

[Soccerkid830]

Hey all, I'm looking for a pointer or two...

I'm trying to decide whether or not to buy an amp to supplement my 809. I'm currently looking at an XPA-5 or 3, probably going to wait for the next sale Emo throws no matter what I decide, IF I decide to get one. At any rate, I ran through some math calculations that I think I've seen floating around here and determined that my receiver is only pushing infinitesimal amounts of wattage.

Someone correct my math here, as it seems too low to myself...
As I typically watch TV, the volume is at ~45-50 db. We'll just assume 50 db in this regard to make the math easier.
My speakers have a sensitivity of 92 dB/W/M. Which means they will produce sound at 92 dB at a distance of 1 meter, when powered with 1 watt. So, every meter away, you double wattage. I sit ~10 feet away, so that's ~3 meters. 1W->2W->4W for 92 dB at ~10 feet away. Now, I listen typically around 50 dB, and you divide wattage by two, every 3 dB down?

So 92-89-86-83-80-77-74-71-68-65-62-59-56-53-50.

That's 14 halves from 92 assuming I still know how to count . Now, if I did the math right, that's roughly 0.000244 watts. Did I do something wrong? That seems way too low


Nonetheless, when I do watch movies, I'll turn them up to around 90 dB if I'm lucky, (I got them pesky neighbors at the next apartment over who will promptly call my landlord should they hear even a smudge of noise through the walls). So at this point, am I really only using the single watt of power to these speakers? Is there even a reason to buy an amp in this case?
According to what I just calculated, I'd be just throwing money into a pit of fire by buying an amplifier.

Anyone feel like touching on this for me and correcting my math?

Thanks in advance,
Tim

 

[j_garcia]

The real deal is, math or not, if you aren't pushing the limits of your speakers at the levels you are listening at (you can't crank it because of your neighbors?) , then an amp won't do anything for you.

Your neighbors can't do ANYTHING about your listening as long as it is during the "normal" hours of the day.... If your landlord is on your neighbor's side of things with respect to what you do in your own apartment, move.

 

[Soccerkid830]

The real deal is, math or not, if you aren't pushing the limits of your speakers at the levels you are listening at (you can't crank it because of your neighbors?) , then an amp won't do anything for you.

Your neighbors can't do ANYTHING about your listening as long as it is during the "normal" hours of the day.... If your landlord is on your neighbor's side of things with respect to what you do in your own apartment, move.

He's not necessarily on their side, they just go to him first instead of coming over next door to ask me to turn them down. There are four apartments in the building, one is an older lady in her 40s-50s or so, one is a professor at my school, and the ONLY neighbor that complains is another student .

Moving isn't really in the picture at this point til I'm done with school. The location is nice and close to campus, rent is fairly low compared to similar places, and I'm tied down with a lease.


The main question I'm asking though is... Was that math right? It just seems way too low to myself. That would mean it's taking less electricity to power my speakers than lighting a typical LED light....

 

[j_garcia]

No, I don't think your math is quite correct since there are a huge number of factors. That sensitivity is sort of a "generic" measurement, it doesn't take into account what you are playing, as impedance varies with frequency played so the actual draw of the speaker will vary widely depending on what you are listening to. It is true that with normal listening you are using probably using a few watts. During big peaks however, the rule of thumb is about 10X power required, so if you are using say 5W on routine material, that translates into potentially 50W to handle a big peak (explosion for example).

I know how it is being in an apartment and not being able to move. I am sure I got complaints before too, since I had a 15" beast of a sub in my previous apartment But since I always turned it down after 10pm, the management never said anything to me.

 

[PENG]

Aside from what John said, your math is still incorrect. Every time you double the distance SPL drops by 6 db. Depending on your room, you do get some reinforcement so the net loss will typically be somewhat less.

 

[Soccerkid830]

Thanks for the responses.

At this point, I think I'll just hold off on the amp then. At least until I graduate and get my own place without sharing walls with my neighbors.

I know how it is being in an apartment and not being able to move. I am sure I got complaints before too, since I had a 15" beast of a sub in my previous apartment But since I always turned it down after 10pm, the management never said anything to me.

I have RBH T2P towers as fronts and I rarely even turn on the sub amps to avoid pissing off my neighbors (the speakers are going home over Spring Break). Sure they can't legally do anything, but I'd rather not be an a$$ to them at the same time. This is why I didn't even bother to bring my new dual FV15HP's to my apartment, I just put them back into their boxes and threw em down the stairs at my parent's house, which is where the T2's will also be going for the time being.

 

[zhimbo]

Your neighbors can't do ANYTHING about your listening as long as it is during the "normal" hours of the day.... If your landlord is on your neighbor's side of things with respect to what you do in your own apartment, move.

If it worked as you claimed, that means you could have an airhorn and vuvuzuela orchestra going in your apartment all day long, as long as it stopped promptly at the end of "normal hours".

It isn't that simple at all, certainly not where I've lived. If neighbors hear the sound, that means you're making sound in THEIR apartment. There are, of course, different levels of tolerance, and different leases and different local laws and regulations, but you can't actually assume you can make any sound you like, "normal hours" included. Some cities will actually spell out dB levels and/or durations.

 

[j_garcia]

If it worked as you claimed, that means you could have an airhorn and vuvuzuela orchestra going in your apartment all day long, as long as it stopped promptly at the end of "normal hours".

It isn't that simple at all, certainly not where I've lived. If neighbors hear the sound, that means you're making sound in THEIR apartment. There are, of course, different levels of tolerance, and different leases and different local laws and regulations, but you can't actually assume you can make any sound you like, "normal hours" included. Some cities will actually spell out dB levels and/or durations.

Obviously, some places have limits and management could advise or request that you be more reasonable. However living in an apartment is a two way (or more) street. Yes, it is a given that one needs to be considerate and not obnoxious. On the same note, in an apartment setting, one HAS to expect they will hear their neighbors. There is no getting around it, that's one of the big sacrifices you make living in an apartment. If it isn't breaking the law, nobody can tell me what I can and can't do in my own residence.

I am moving from my current rental house to an apartment and the system is a big consideration for me, because I know I won't be able to listen at the levels I currently enjoy as often as I do or at all. I will most likely need to downsize the system and move most of it up to our house where we spend less time because I currently need to live near my job. It sucks, but with the kids out of the house, I don't need that big of a place here anymore and the apartment saves me a few hundred a month and gets me closer to work.

 

[PENG]

At this point, I think I'll just hold off on the amp then. At least until I graduate and get my own place without sharing walls with my neighbors.

That seems like the right thing to do. The 809 should do fine on its own.

 

[zhimbo]

If it isn't breaking the law, nobody can tell me what I can and can't do in my own residence.

I agree with nearly everything you say, (two-way street, etc.), but this sentence, as it turns out, isn't true. Landlords certainly CAN tell you what and what not to do, even if the activity itself is perfectly legal. They can tell you not to smoke, not to own a pet...and tell you to keep the noise down, too, if they need to step in to a tenant dispute. This is generally only true if there are clauses in the lease, but I've never had a lease that didn't have at least some mention of noise issues.

I'm not commenting on SoccerKid's particular situation (or yours).

 

[Soccerkid830]

That's the thing, my landlord actually has told them to deal with it. The last time they called him on me was a Friday night at about 7:30 pm. He told them to deal with it, and called me and said they were complaining, and just to keep it down once it gets later into the evening.

And as I said before, I don't want to make an enemy with my neighbors, I'd just appreciate it more if they came straight to me rather than bringing our landlord into something he doesn't need to waste his time with. I've went to their apartment to talk with them but they won't acknowledge it. This is what happens when you go to an engineering school and you're neighbors with stereotypical engineers who cannot communicate


I just ran a quick search and found our noise ordinance here is in effect from 11 pm to 7 am. The cut off for being too loud is if you can clearly hear the sound from 40 ft away outside, which, I'm nowhere near for the record .

 

[zhimbo]

I just ran a quick search and found our noise ordinance here is in effect from 11 pm to 7 am. The cut off for being too loud is if you can clearly hear the sound from 40 ft away outside, which, I'm nowhere near for the record .

You've done your homework, that's good. But, yeah, sometimes you do need to manage relations with the neighbors regardless of whether you're "in the right" or whatever.

I guess we're a bit off-topic, but I think the orignal question has been answered anyway. Yeah, hold off on the amp.

 

[Crackerballer]

To keep beating this dead horse, just because you aren't doing anything illegal doesn't mean they couldn't be an a$$ about it or cause you problems by annoying your landlord to the point that he HAS to say something to you just for his personal sanity.

Back on topic, don't worry about the math as much as your listening levels and I agree with everyone else, your situation/equipment doesn't merit an amp.

 

[walter duque]

That's the thing, my landlord actually has told them to deal with it. The last time they called him on me was a Friday night at about 7:30 pm. He told them to deal with it, and called me and said they were complaining, and just to keep it down once it gets later into the evening.

And as I said before, I don't want to make an enemy with my neighbors, I'd just appreciate it more if they came straight to me rather than bringing our landlord into something he doesn't need to waste his time with. I've went to their apartment to talk with them but they won't acknowledge it. This is what happens when you go to an engineering school and you're neighbors with stereotypical engineers who cannot communicate


I just ran a quick search and found our noise ordinance here is in effect from 11 pm to 7 am. The cut off for being too loud is if you can clearly hear the sound from 40 ft away outside, which, I'm nowhere near for the record .

I feel bad for you, you can't even enjoy your system. I guess I am lucky, I live in an apartment complex too. What you have to do is get your neighbors used to it. I have mine trained. I got 4 subs, 5800 watts of total power and only one time my neighbor came over and showed me the picture that unhooked on her wall, and she was cool about it. Standard listening volume for me is around 110 db, at times I get a little crazy (maybe 5 minutes or so) and I turn it up a few notches. After 7 pm I'll take it down to around 80 db out of respect.

 

[markw]

Let's be honest here, Walter.

I feel bad for you, you can't even enjoy your system. I guess I am lucky, I live in an apartment complex too. What you have to do is get your neighbors used to it. I have mine trained. I got 4 subs, 5800 watts of total power and only one time my neighbor came over and showed me the picture that unhooked on her wall, and she was cool about it. Standard listening volume for me is around 110 db, at times I get a little crazy (maybe 5 minutes or so) and I turn it up a few notches. After 7 pm I'll take it down to around 80 db out of respect.

Your neighbors have long since gone stone deaf from all the noise from your apartment. That, and they can't tell if the gunshots are real or they're Memorex.

 

[j_garcia]

I feel bad for you, you can't even enjoy your system. I guess I am lucky, I live in an apartment complex too. What you have to do is get your neighbors used to it. I have mine trained. I got 4 subs, 5800 watts of total power and only one time my neighbor came over and showed me the picture that unhooked on her wall, and she was cool about it. Standard listening volume for me is around 110 db, at times I get a little crazy (maybe 5 minutes or so) and I turn it up a few notches. After 7 pm I'll take it down to around 80 db out of respect.

That likely has more to do with the fact that your neighbor isn't an asshat like the OPs.

 

[walter duque]

Your neighbors have long since gone stone deaf from all the noise from your apartment. That, and they can't tell if the gunshots are real or they're Memorex.

Now why do you have to let everyone know that I live in the ghetto. Lol

 

[Soccerkid830]

Thanks for the suggestions guys.

I'll just cross my fingers that my neighbors are graduating this year and won't be here next year . Or maybe they'll just be sick of hearing it and move away anyway. Either way would be fine by me

 

[DS-21]

Hey all, I'm looking for a pointer or two...

I'm trying to decide whether or not to buy an amp to supplement my 809.

No.

Think about it. If you have to think about it, the answer is going to be "no."

Signs that one actually needs an external amp are quite audible.

Now, if you want to buy another box (one not certified as safe by any NRTL-certified independent ratings agency - I looked at and heard a friend's Emo amp earlier this evening, and could not help but notice that it lacked UL or ETL certification badging on the back panel) just to buy another audio box - the reason most people buy external amps, frankly - then perhaps think about it.

I ran through some math calculations that I think I've seen floating around here and determined that my receiver is only pushing infinitesimal amounts of wattage.

Someone correct my math here, as it seems too low to myself...
As I typically watch TV, the volume is at ~45-50 db. We'll just assume 50 db in this regard to make the math easier.

First, I doubt the volume knob tracks accurately down there. That is to say, I doubt that -45 is really 45dB less than reference (85dB average on calibrated program material, 105dB at 0dBFS on everything). A building would have to be very quiet to support an average listening level of 40dB, which is roughly a loud whisper from someone arm's length away. Furthermore, if you use a Audyssey DynamicEQ (which I highly recommend doing in any case), the control certainly isn't linear, because of the bass and surround boost.

However, IF one makes the assumption that (a) your speakers' rated efficiency is accurate; and (b) your AVR's volume control is where it says it is, then you need to account for peaks of 60dB at the listening position. Let's add 5dB to that to get 1m levels, a fudge factor combining the falloff of direct sound and reflections. So 65dB. To get 65dB from 92dB/W/m speakers, one needs rather less than a watt.

But you can determine your actual requirements fairly easily. There's an interesting test by Pano in the multiway speaker forum at diyaudio.com that you can use. Basically, it involves listening to program material to set the volume, and then playing a downloaded test tone with the probes of a multimeter stuck in your speakers' binding posts to see what voltage the amp is running at that volume.

But based on what you've written, I'll be surprised if more than 2-3 watts are used. So maybe instead of an Emo bruiser you should be looking at a dainty little SET or T-amp!

 

[Soccerkid830]

No.

Think about it. If you have to think about it, the answer is going to be "no."

Signs that one actually needs an external amp are quite audible.

Now, if you want to buy another box (one not certified as safe by any NRTL-certified independent ratings agency - I looked at and heard a friend's Emo amp earlier this evening, and could not help but notice that it lacked UL or ETL certification badging on the back panel) just to buy another audio box - the reason most people buy external amps, frankly - then perhaps think about it.



First, I doubt the volume knob tracks accurately down there. That is to say, I doubt that -45 is really 45dB less than reference (85dB average on calibrated program material, 105dB at 0dBFS on everything). A building would have to be very quiet to support an average listening level of 40dB, which is roughly a loud whisper from someone arm's length away. Furthermore, if you use a Audyssey DynamicEQ (which I highly recommend doing in any case), the control certainly isn't linear, because of the bass and surround boost.

However, IF one makes the assumption that (a) your speakers' rated efficiency is accurate; and (b) your AVR's volume control is where it says it is, then you need to account for peaks of 60dB at the listening position. Let's add 5dB to that to get 1m levels, a fudge factor combining the falloff of direct sound and reflections. So 65dB. To get 65dB from 92dB/W/m speakers, one needs rather less than a watt.

But you can determine your actual requirements fairly easily. There's an interesting test by Pano in the multiway speaker forum at diyaudio.com that you can use. Basically, it involves listening to program material to set the volume, and then playing a downloaded test tone with the probes of a multimeter stuck in your speakers' binding posts to see what voltage the amp is running at that volume.

But based on what you've written, I'll be surprised if more than 2-3 watts are used. So maybe instead of an Emo bruiser you should be looking at a dainty little SET or T-amp!

I actually used an SPL meter to get those readings, not the control on the receiver itself. My roommate didn't understand the whole -XX dB concept and that a less negative number was higher volume, so I just set it to regular numbers so it goes from 0-100 I believe, I have only set it to 82 a couple times that's where it says (ref) and haven't gone past that, so who knows if it goes to 100, but I would guess it does.

Thanks for the info though!