How do I get my 6 7" woofers moving?

[guitarplyrstevo]

I own a pair of RTi12's and I really want to get the 6 7" woofers moving to get the biggest sound possible. Right now I only have an Onkyo TX-SR574 so its only putting out 80w per channel and it doesn't have any preamp outs. I was thinking about upgrading my receiver in the future and maybe geting a Behringer EP2500 so I can get 300w per side but does that mean that the overall sound will be louder? I don't really need a lot of volume, I really just want to get these speakers moving some air. What are some ways I can achieve this? Or is the only way to crank up the volume really loud?

 

[fmw]

Your system doesn't play loud enough with your receiver?

 

[Nomo]

I own a pair of RTi12's and I really want to get the 6 7" woofers moving to get the biggest sound possible. Right now I only have an Onkyo TX-SR574 so its only putting out 80w per channel and it doesn't have any preamp outs. I was thinking about upgrading my receiver in the future and maybe geting a Behringer EP2500 so I can get 300w per side but does that mean that the overall sound will be louder? I don't really need a lot of volume, I really just want to get these speakers moving some air. What are some ways I can achieve this? Or is the only way to crank up the volume really loud?

These are the 7" woofers that will be playing in a 9' x 9' room?
Maybe those speakers like power, but in that room you shold get plenty of volume from even that receiver.

Your ears may thank you some day.

 

[Midcow2]

What Sound Are You Looking For?

I own a pair of RTi12's and I really want to get the 6 7" woofers moving to get the biggest sound possible. Right now I only have an Onkyo TX-SR574 so its only putting out 80w per channel and it doesn't have any preamp outs. I was thinking about upgrading my receiver in the future and maybe geting a Behringer EP2500 so I can get 300w per side but does that mean that the overall sound will be louder? I don't really need a lot of volume, I really just want to get these speakers moving some air. What are some ways I can achieve this? Or is the only way to crank up the volume really loud?

It sounds like you need a SVS subwoofer from PB10-NSD ( $429) to PB13-Ultra($1399).

The Polk RTi12s have a average effciency (90 dB) so they should be able to provide pretty loud sound out of the SR574.

Also, remember that power rating is logrithmic. so increasing from 80RMS to 300RMS is only a about a 57% increase. While the RTi12s are rated up to 500RMS, you best bet would be a Hsu or SVS subwoofer.

 

[markw]

how loud is loud?

To double the apparant loudness of a what you hear from a speaker, you need an amp that puts out about ten times the power that your current amp puts out.

just buy a sub...

 

[mike c]

If you follow only two simple rules in this life, you will do well.
#1 - Never tell anyone everything you know.

nice.

 

[TLS Guy]

I own a pair of RTi12's and I really want to get the 6 7" woofers moving to get the biggest sound possible. Right now I only have an Onkyo TX-SR574 so its only putting out 80w per channel and it doesn't have any preamp outs. I was thinking about upgrading my receiver in the future and maybe geting a Behringer EP2500 so I can get 300w per side but does that mean that the overall sound will be louder? I don't really need a lot of volume, I really just want to get these speakers moving some air. What are some ways I can achieve this? Or is the only way to crank up the volume really loud?

What do you mean by moving air? Sound travels in air like ripples in a pond after casting a stone. We are talking about traveling waves of pressure and to and fro displacement.

When you see a loudspeaker cone moving violently, that generally means wasted effort and a driver decoupled. If a driver is properly loaded it moves very little. In a ported enclosure, TL and especially a horn the pressure is so high behind the speaker it barely moves at all. The output comes from the ports or horn mouth. That is where the low frequency sound waves are emanating from.
Below tuning the cone travel increases, but it is wasted effort and not producing sound.

Take a look at at this file posted in another thread, modeling a kappa perfect 12. Go to the graph showing cone displacement. You will see that where the sub is outputting deep bass, the cone is barely moving. Below F3 the cone displacement picks up, but this is wasted effort and audio output rapidly falls away, but it is "moving air."

Now a sealed enclosure only has the driver to radiate the waves of sound. However it is relatively inefficient, as a loudspeaker cone is not a particularly efficient coupler to the air in the room.

So your speakers are loud enough or not. Remember we listen to speakers with our ears, not our eyes. If it is cone movement you want to watch, get a sealed speaker. Yours speakers are ported, and from your observations, the cones are properly loaded by the box tuning.

 

[guitarplyrstevo]

What do you mean by moving air? Sound travels in air like ripples in a pond after casting a stone. We are talking about traveling waves of pressure and to and fro displacement.

When you see a loudspeaker cone moving violently, that generally means wasted effort and a driver decoupled. If a driver is properly loaded it moves very little. In a ported enclosure, TL and especially a horn the pressure is so high behind the speaker it barely moves at all. The output comes from the ports or horn mouth. That is where the low frequency sound waves are emanating from.
Below tuning the cone travel increases, but it is wasted effort and not producing sound.

Take a look at at this file posted in another thread, modeling a kappa perfect 12. Go to the graph showing cone displacement. You will see that where the sub is outputting deep bass, the cone is barely moving. Below F3 the cone displacement picks up, but this is wasted effort and audio output rapidly falls away, but it is "moving air."


I am not trying to get more volume. I want a bigger sound at lower volumes
Now a sealed enclosure only has the driver to radiate the waves of sound. However it is relatively inefficient, as a loudspeaker cone is not a particularly efficient coupler to the air in the room.

So your speakers are loud enough or not. Remember we listen to speakers with our ears, not our eyes. If it is cone movement you want to watch, get a sealed speaker. Yours speakers are ported, and from your observations, the cones are properly loaded by the box tuning.

I'm sorry I guess that wasn't clear. I shouldn't have said I am trying to get them moving. What I am trying to achieve is more punch in my system while keeping the volume at listening levels. The RTi12's are amazing speakers and I've heard that if you give them enough power, you don't need a subwoofer. In the future I might experiment with a power amp to see what kind of results I will get, but does this mean that the overall volume will be greater or will it sound much bigger because there is more power to the speakers? If you have 300 watts going to each speaker, does it mean that only at high volumes will you take advantage of the 300 watts per side or will it sound just as good at lower volumes?


To everyone: I am not trying to get more volume. The receiver I have already is loud enough, however I want the 6 7" woofers to actually sound like woofers without having to crank it up to extreme levels.

 

[bandphan]

If you have 300 watts going to each speaker, does it mean that only at high volumes will you take advantage of the 300 watts per side or will it sound just as good at lower volumes?

first get a sub, second the room, as mentioned, isnt deserving of an amp that size.

 

[guitarplyrstevo]

first get a sub, second the room, as mentioned, isnt deserving of an amp that size.

I have a sub, just not an SVS or HSU, and the room will probably stay the same but that doesn't tell me anything. I just want to compare how speakers will sound like with appropriate power. For example:

Two RTi12's running at 80 watts per side at 50 db's.
vs
Two RTi12's running at 300 watts per side at 50 db's.

How will the sound compare? The actual SPL will be the same since they are both 50 db's but will there be more low end or more mids or anything differently because the speakers are supplied with more power?

 

[mike c]

I have a sub, just not an SVS or HSU, and the room will probably stay the same but that doesn't tell me anything. I just want to compare how speakers will sound like with appropriate power. For example:

Two RTi12's running at 80 watts per side at 50 db's.
vs
Two RTi12's running at 300 watts per side at 50 db's.

How will the sound compare? The actual SPL will be the same since they are both 50 db's but will there be more low end or more mids or anything differently because the speakers are supplied with more power?

they will sound exactly the same.

oh, my towers have dual 8's with 360watts behind them ... no bass from towers will beat a dedicated subwoofer (even if it isn't an SVS or HSU)

most you can do is have an EQ boost at around 100hz (where most bass boosts are located)

 

[TLS Guy]

I'm sorry I guess that wasn't clear. I shouldn't have said I am trying to get them moving. What I am trying to achieve is more punch in my system while keeping the volume at listening levels. The RTi12's are amazing speakers and I've heard that if you give them enough power, you don't need a subwoofer. In the future I might experiment with a power amp to see what kind of results I will get, but does this mean that the overall volume will be greater or will it sound much bigger because there is more power to the speakers? If you have 300 watts going to each speaker, does it mean that only at high volumes will you take advantage of the 300 watts per side or will it sound just as good at lower volumes?


To everyone: I am not trying to get more volume. The receiver I have already is loud enough, however I want the 6 7" woofers to actually sound like woofers without having to crank it up to extreme levels.

Well that clears things up. You will not change the balance of your speakers by changing amplification. The specs are as usual sparse, but they are nominally eight ohms and fairly sensitive. The minimum impedance is not stated, nor is the relationship of phase and current. However Polk aim their speakers at the receiver market, and I'm not aware of them being an unusually difficult drive.

Even if it were a difficult drive, it would not change the balance of the speaker. Remember there is only one signal. The current can only flow in one direction at a given magnitude at an instant. The point is that if you drive a speaker that requires high current delivery to the bass section, not unusual, with an amp with inadequate current reserve, the bass section will suck the current. The result is clipping and distortion, which will be most audible in the higher frequencies, so you have to turn down the average volume to make things sound pleasant and keep the amp out of clipping.

So you just don't like the balance of your speakers. Does your room have openings that could be causing bass leakage?

Now the F3 of your speakers is 30 Hz, which is a pretty low note. A sub will give you a further half octave extension. Now when people have the complaint you have it generally means you are dissatisfied with the upper base to midrange balance. Now this can be covered up with overdriving a sub, but it is still not accurate.

I have never heard those speakers, so I can't comment. My strong hunch is that there is something you don't like about the voicing of those speakers in their current environment. Whether your benchmark reference is correct or Mathew Polk's I can't say. But you won't change what you don't like about them with a different amp, I doubt. It would be worth experimenting with a good sub though.

 

[guitarplyrstevo]

they will sound exactly the same.

oh, my towers have dual 8's with 360watts behind them ... no bass from towers will beat a dedicated subwoofer (even if it isn't an SVS or HSU)

most you can do is have an EQ boost at around 100hz (where most bass boosts are located)

THANK YOU. That is all I needed to know. So 300 watts will do no good if you don't turn it up. I had this idea that a speaker will sound a lot fuller sounding with more power behind it even at lower volumes.

 

[guitarplyrstevo]

Well that clears things up. You will not change the balance of your speakers by changing amplification. The specs are as usual sparse, but they are nominally eight ohms and fairly sensitive. The minimum impedance is not stated, nor is the relationship of phase and current. However Polk aim their speakers at the receiver market, and I'm not aware of them being an unusually difficult drive.

Even if it were a difficult drive, it would not change the balance of the speaker. Remember there is only one signal. The current can only flow in one direction at a given magnitude at an instant. The point is that if you drive a speaker that requires high current delivery to the bass section, not unusual, with an amp with inadequate current reserve, the bass section will suck the current. The result is clipping and distortion, which will be most audible in the higher frequencies, so you have to turn down the average volume to make things sound pleasant and keep the amp out of clipping.

So you just don't like the balance of your speakers. Does your room have openings that could be causing bass leakage?

Now the F3 of your speakers is 30 Hz, which is a pretty low note. A sub will give you a further half octave extension. Now when people have the complaint you have it generally means you are dissatisfied with the upper base to midrange balance. Now this can be covered up with overdriving a sub, but it is still not accurate.

I have never heard those speakers, so I can't comment. My strong hunch is that there is something you don't like about the voicing of those speakers in their current environment. Whether your benchmark reference is correct or Mathew Polk's I can't say. But you won't change what you don't like about them with a different amp, I doubt. It would be worth experimenting with a good sub though.

Ah that makes a lot of sense. But that leads to another question. At my job we have one 8" Polk Momo and has spently of bass. Why cant the 6 7" woofers in the RTi12's produce bass like that? There is far more surface area on 6 7" woofers than there is on just 1 8" woofer. I understand that there is a minimum of 200 watts driving the Momo sub woofer so that is why I thought supplying the speaker with more power will do exactly that.

 

[mike c]

THANK YOU. That is all I needed to know. So 300 watts will do no good if you don't turn it up. I had this idea that a speaker will sound a lot fuller sounding with more power behind it even at lower volumes.

speaker sound will only be affected if you compare an amp that can't handle the load and an amp that can.

in this case, this is not relevant.

you are welcome.

does your receiver have a bass boost? (treble and bass knobs are pretty common)

what is your source? on PC sources, there are default bass boosts on winamp

 

[guitarplyrstevo]

speaker sound will only be affected if you compare an amp that can't handle the load and an amp that can.

in this case, this is not relevant.

you are welcome.

does your receiver have a bass boost? (treble and bass knobs are pretty common)

what is your source? on PC sources, there are default bass boosts on winamp

It does have bass boost but any more than 2 db's of boosted bass results in a boomy sound. The EQ on winamp sucks. It always made any speakers I have sound less natural.

 

[mike c]

the winamp EQ takes getting used to ... now i always use "full treble and full bass"

try experimenting with the EQ boosts manually, see which frequency you like boosted

you might have some sort of bass null at your listening position, try experimenting with different speaker OR listening positions

i have Rti4 speakers on my PC btw.

 

[markw]

It does have bass boost but any more than 2 db's of boosted bass results in a boomy sound. The EQ on winamp sucks. It always made any speakers I have sound less natural.

This might indicate that your speakers don't really put out the bass you crave. No matter how much power you feed them they will still sound "boomy".

Can you insert a real eq into your circuit?

 

[TLS Guy]

Ah that makes a lot of sense. But that leads to another question. At my job we have one 8" Polk Momo and has spently of bass. Why cant the 6 7" woofers in the RTi12's produce bass like that? There is far more surface area on 6 7" woofers than there is on just 1 8" woofer. I understand that there is a minimum of 200 watts driving the Momo sub woofer so that is why I thought supplying the speaker with more power will do exactly that.

You do insist on putting a guy on the spot!

Now from your "handle" I suspect your are a musician, and have some reasonable sphere of audio reference. If that is so, and you have played in groups you know the importance of audio balance.

A good speaker is at its core a well balanced one. The problem is it takes a lot of experience to judge where the lack of balance lies. It is so often not where people think it is.

Now your speakers have an F3 of 30 Hz. As I said before, they are in fact producing a lot of bass. They are do not start to reduce output until 30 Hz, a low note. Now I had a look at that NOMO driver and did a dead reckon. Its Fs is 43 Hz. I have not done a full model, but I see no scenario where you could build a speaker where that car driver had an F3 of 30 Hz.

Now you state that if you Eq the bass it becomes boomy, further reinforcing the fact that your speakers have plenty of lower bass, and that Polk did not lie in their specs. The F3 almost certainly is 30 Hz.

So the problem with your speakers almost certainly lies above 100 Hz.

Now I have not heard your speakers, but I can hazard a good guess as to the likely problem. The speakers are a three way with passive crossovers at 120 Hz and 1.8 KHz. Having myself learned in the world of hard knocks, I can tell you a passive crossover at 120 Hz is a nightmare. Flat out I would not do it.
The odds of those speakers having a very untidy crossover at that point is over whelming in my view. The reason being is that the inductor and capacitor values become huge, and introduce all kinds of unpleasant side effects. If you want a crossover in that region, in my view it has to be a powered electronic crossover and two amps. That problem would certainly account for what you are noticing.

Now if you add bass from a sub and crossover at 80 or 100 Hz, you still have the problem. In fact to mask the problem there will be a tendency to run the sub or subs a little hot. So you may be happier, but from what you have noticed, and if you have a critical ear, you will still be dissatisfied I'm afraid.

 

[guitarplyrstevo]

You do insist on putting a guy on the spot!

Now from your "handle" I suspect your are a musician, and have some reasonable sphere of audio reference. If that is so, and you have played in groups you know the importance of audio balance.

A good speaker is at its core a well balanced one. The problem is it takes a lot of experience to judge where the lack of balance lies. It is so often not where people think it is.

Now your speakers have an F3 of 30 Hz. As I said before, they are in fact producing a lot of bass. They are do not start to reduce output until 30 Hz, a low note. Now I had a look at that NOMO driver and did a dead reckon. Its Fs is 43 Hz. I have not done a full model, but I see no scenario where you could build a speaker where that car driver had an F3 of 30 Hz.

Now you state that if you Eq the bass it becomes boomy, further reinforcing the fact that your speakers have plenty of lower bass, and that Polk did not lie in their specs. The F3 almost certainly is 30 Hz.

So the problem with your speakers almost certainly lies above 100 Hz.

Now I have not heard your speakers, but I can hazard a good guess as to the likely problem. The speakers are a three way with passive crossovers at 120 Hz and 1.8 KHz. Having myself learned in the world of hard knocks, I can tell you a passive crossover at 120 Hz is a nightmare. Flat out I would not do it.
The odds of those speakers having a very untidy crossover at that point is over whelming in my view. The reason being is that the inductor and capacitor values become huge, and introduce all kinds of unpleasant side effects. If you want a crossover in that region, in my view it has to be a powered electronic crossover and two amps. That problem would certainly account for what you are noticing.

Now if you add bass from a sub and crossover at 80 or 100 Hz, you still have the problem. In fact to mask the problem there will be a tendency to run the sub or subs a little hot. So you may be happier, but from what you have noticed, and if you have a critical ear, you will still be dissatisfied I'm afraid.

Actually I have tested it myself with a sine wave program and the bass actually drops in volume at around 60hz. I set the crossover on my receiver at 60hz so the subwoofer will continue what the RTi12's cannot produce. I understand what you are saying though but is it possible to just add a powered crossover and amps to a tower?

By the way, how did you know I am a musician?