Setting up a Sub Woofer???

[GTM]

Wow, really! I'll try to get my dB metre out tomorrow.

Soooo, that being the case, I wonder if this XLS200 Sub is actually any use to me whatsoever? It's range is 120-40hz

Yup... I'm amazed you even feel the need for a sub to be honest. Nothing.. and I mean nothing does bass in the same qualitative way as a speaker with horn loaded bass such as the H2. Horns drive the room in way that no standard sub with a 10" driver could ever achieve. Might go louder but it won't have the quality if a good horn speaker like the H2. No ported sub is ever going to match the dynamics of a good rear loaded horn speaker in the bass region. I'd say you're just messing up the speakers bass quality personally. If you're not getting enough bass from the H2's it's because you've got them too far away from the corners. Speakers such as the H2 are designed to be used with boundary reinforcement. They don't give their best in the middle of the room.

A review at the time measured the H2 flat down to 30hz with a -6db point of 27hz (in room). That's typical of quarter wave horns at their low end they drop off like a port, (but without any of the crappy port effects). I'd say your sub isn't up to the task. For a start it's lowest cut off frequency is too high, it will need to be down at sub 30hz to have a chance of integrating properly. A sub upper cut off shouldn't ever be set higher than the -3db point of the speaker, or else you will get a peak in the bass response. So whilst the sub you have does go lower, (-6db at 17hz) it extends too far up IMO. Though in all honesty unless you're listening to electronically produced bass, (or organ music maybe), there will be no content of any significance between 17hz and 27hz in any music.

http://www.acoustica.org.uk/impulse/impulse.html

 

[GTM]

....

Yes, not looking for Booming bass. just like to feel the kick drum though. I think most hifi enthusiasts never hear a kick drum, yet claim their system sounds like Live music...how does that work?

The feel from a bass drum isn't achieved from lower frequencies. Bass drums don't actually have a lot of very low frequency content. That kick that you're referring to, (presumably through PA systems) comes purely from the volume and the way the drum has been eq'd.

http://www.moultonlabs.com/more/principles_of_multitrack_mixing_the_kick_drum_bass_relationship/P1/

 

[strummer]

They have big ATC actives and a big room. That's how that works.

Yeah, I'm talking about "the others". The ones with 'ickle speakers.

Yup... I'm amazed you even feel the need for a sub to be honest. Nothing.. and I mean nothing does bass in the same qualitative way as a speaker with horn loaded bass such as the H2. Horns drive the room in way that no standard sub with a 10" driver could ever achieve. Might go louder but it won't have the quality if a good horn speaker like the H2. No ported sub is ever going to match the dynamics of a good rear loaded horn speaker in the bass region. I'd say you're just messing up the speakers bass quality personally. If you're not getting enough bass from the H2's it's because you've got them too far away from the corners. Speakers such as the H2 are designed to be used with boundary reinforcement. They don't give their best in the middle of the room.

A review at the time measured the H2 flat down to 30hz with a -6db point of 27hz (in room). That's typical of quarter wave horns at their low end they drop off like a port, (but without any of the crappy port effects). I'd say your sub isn't up to the task. For a start it's lowest cut off frequency is too high, it will need to be down at sub 30hz to have a chance of integrating properly. A sub upper cut off shouldn't ever be set higher than the -3db point of the speaker, or else you will get a peak in the bass response. So whilst the sub you have does go lower, (-6db at 17hz) it extends too far up IMO. Though in all honesty unless you're listening to electronically produced bass, (or organ music maybe), there will be no content of any significance between 17hz and 27hz in any music.

http://www.acoustica.org.uk/impulse/impulse.html

The feel from a bass drum isn't achieved from lower frequencies. Bass drums don't actually have a lot of very low frequency content. That kick that you're referring to, (presumably through PA systems) comes purely from the volume and the way the drum has been eq'd.

http://www.moultonlabs.com/more/principles_of_multitrack_mixing_the_kick_drum_bass_relationship/P1/

Thanks GTM, some really interesting stuff there!

I never felt the bass was lacking, I was just interested to see what could be. I was surprised to hear that Fox (an ATC 100 owner) uses Subs, so wondered if they could add anything here.

I know what you mean about placement of the Impulse H2s. I don't like them at all if they are even a few inches from the wall, I have mine close to touching the back wall. Not in corners though, are you saying they'll work better there? Right in the corner at 45deg??

Agree with everything you've said about the Sub. It's clearly not bringing anything. OK, maybe a bit of obvious bass, which is OK on some TV use, but in terms of Music, nah!


Thanks

 

[Fox]

I said you didn't need to add a sub.

If done right monolith sub plus ATC100s adds a bit more weight to the bass end. Its does not really extend the bass response of the 100s but adds extra energy (as martin alluded to, and I said in another post you will have a long search if you want to improve the H2s bass response, an extra driver will do what I do, add mass, that's it). In some of the work I have been composing this extra energy is exceptionally important for clarity and getting closer to the sound I use live (with a line array of 18" Mackie Actives)

At home I can do it a few ways

1. I can add a single summed stereo (mono) sub to a pair of 100s. I do this.
2. I can get a pair of matched stereo subs (live usually placed together side by side centre to LR Main monitors)
3. I can get speakers with a larger driver/surface area/lower -dB/m rolloff point in the FR plot. (i.e. 150s, 200s 300s etc or larger than 12" sub)

All have their uses/proponents/applications. 1 is by far the simplest and a quck and dirty fix. 2 is probably the best *if* installed correctly but needs careful integration. 3 is better for projecting more overall energy deeper into the room, so bigger speakers sometimes needed if going to a bigger house

Sub tuning here is rough and ready and conservative if you choose option one then its possible to do it by ear if you have a week to nudge the EQ here and there (the SPL 2Control makes paging in and out of drivers really really easy). I settled on a level and then pulled back a bit just to be sure. It just adds a bit of body behind things that were not as present as they ought to be when I heard them in real life. If you can hear the sub you are usually setting it too loud. Ideally one would have an intelligent system that profiles subs for the ATCs and Geithains but I use the Geithains without sub as I use them to place sounds in the sound field and to listen out for awkward interactions and a Sub gets in the way. The nearfileds have a very different job to do. A very different target application.

 

[GTM]

.....
I know what you mean about placement of the Impulse H2s. I don't like them at all if they are even a few inches from the wall, I have mine close to touching the back wall. Not in corners though, are you saying they'll work better there? Right in the corner at 45deg??
.......

Well the theory goes like this:

Most (not all) speakers that make use of rear-loaded horns for the bass units, are based on the principle of quarter-wave horn loading. So the length, in combination with the area of the mouth, of the horn determines it's lower operating frequency, in part at least similar to a port. The difference however, (and the whole point of using horn loading in the first place), is that the is that horns provide more efficient acoustic impedance matching of the output of the drive unit to the "real world". Given that the majority of such designs are loosely based between linearly and exponentially expanding horns using the three boundaries of walls and floor in a corner in effect extend both the horns length and mouth area. Thus affecting the tuning and efficiency of the horn. So it would be a case of suck it and see. Another thing to be aware of with horns that open out at the bottom of the cabinet, (such as the H2), is to ensure that you have enough area around the bottom of the speaker and the floor to prevent any reflections back in to the horn. Essentially you need to take the area of the base of the speaker, and ensure that the area of the gap all the way around the speaker between floor and cabinet is at least the same area, or slightly larger.

 

[Nic P]

If the Impulse are -3db at 40hz set the sub between 50-60hz. You're probably better off with a frequency sweep sample, then just dial the level on the sub in until you barely know it's there. Everyone sets them up too loud, way too loud, for music you shouldn't know it's there until its turned off.

I use a budget REL (called a Tsunami) on my stereo AV system (I use tiny infinity satellite speakers which have little bass). The remote provides up to 4 different modes of frequency cut off and level. My music mode is as you describe, but for films I use a more aggressive mode, and for normal telly something in between.

Nic P

 

[strummer]

I said you didn't need to add a sub.

If done right monolith sub plus ATC100s adds a bit more weight to the bass end. Its does not really extend the bass response of the 100s but adds extra energy (as martin alluded to, and I said in another post you will have a long search if you want to improve the H2s bass response, an extra driver will do what I do, add mass, that's it). In some of the work I have been composing this extra energy is exceptionally important for clarity and getting closer to the sound I use live (with a line array of 18" Mackie Actives)

At home I can do it a few ways

1. I can add a single summed stereo (mono) sub to a pair of 100s. I do this.
2. I can get a pair of matched stereo subs (live usually placed together side by side centre to LR Main monitors)
3. I can get speakers with a larger driver/surface area/lower -dB/m rolloff point in the FR plot. (i.e. 150s, 200s 300s etc or larger than 12" sub)

All have their uses/proponents/applications. 1 is by far the simplest and a quck and dirty fix. 2 is probably the best *if* installed correctly but needs careful integration. 3 is better for projecting more overall energy deeper into the room, so bigger speakers sometimes needed if going to a bigger house

Sub tuning here is rough and ready and conservative if you choose option one then its possible to do it by ear if you have a week to nudge the EQ here and there (the SPL 2Control makes paging in and out of drivers really really easy). I settled on a level and then pulled back a bit just to be sure. It just adds a bit of body behind things that were not as present as they ought to be when I heard them in real life. If you can hear the sub you are usually setting it too loud. Ideally one would have an intelligent system that profiles subs for the ATCs and Geithains but I use the Geithains without sub as I use them to place sounds in the sound field and to listen out for awkward interactions and a Sub gets in the way. The nearfileds have a very different job to do. A very different target application.

You did indeed.

I was just interested to see what if anything a Sub might add. I'm satisfied now that the H2s go low enough & there's nothing to be added from a Sub.

The other reason is I am toying with the idea of buying some Active Monitors (ATC, ADAM ???) & just wanted to understand the use of Subs. If I find a pair of Actives that I prefer to the H2s, but don't go as low (as seems likely), then I've got a plan..

Well the theory goes like this:

Most (not all) speakers that make use of rear-loaded horns for the bass units, are based on the principle of quarter-wave horn loading. So the length, in combination with the area of the mouth, of the horn determines it's lower operating frequency, in part at least similar to a port. The difference however, (and the whole point of using horn loading in the first place), is that the is that horns provide more efficient acoustic impedance matching of the output of the drive unit to the "real world". Given that the majority of such designs are loosely based between linearly and exponentially expanding horns using the three boundaries of walls and floor in a corner in effect extend both the horns length and mouth area. Thus affecting the tuning and efficiency of the horn. So it would be a case of suck it and see. Another thing to be aware of with horns that open out at the bottom of the cabinet, (such as the H2), is to ensure that you have enough area around the bottom of the speaker and the floor to prevent any reflections back in to the horn. Essentially you need to take the area of the base of the speaker, and ensure that the area of the gap all the way around the speaker between floor and cabinet is at least the same area, or slightly larger.

GTM, you have an ability to explain things in a way a thick get like me, with minimal understanding, can understand. The bit a don't understand is that last bit, I've got them shoved hard against the back wall. Are you saying I need to raise the height?? I've heard the H2 has an equivalent 20" driver...is that true?? So how would I calculate the area/height needed? At the moment they are 40mm above the carpet & hard against the back wall.

 

[Blzebub]

You did indeed.

I was just interested to see what if anything a Sub might add. I'm satisfied now that the H2s go low enough & there's nothing to be added from a Sub.

The other reason is I am toying with the idea of buying some Active Monitors (ATC, ADAM ???) & just wanted to understand the use of Subs. If I find a pair of Actives that I prefer to the H2s, but don't go as low (as seems likely), then I've got a plan..

If you are thinking of ATCs, phone ATC direct and ask them which speakers will work best with your room. They'll no doubt give advice on whether you need a sub or not. I forgot to ask about subs when I was on the phone recently, but I imagine (but don't know for sure) that it would be superfluous.

I'm getting sublessness anxiety now. ;-)

 

[strummer]

If you are thinking of ATCs, phone ATC direct and ask them which speakers will work best with your room. They'll no doubt give advice on whether you need a sub or not. I forgot to ask about subs when I was on the phone recently, but I imagine (but don't know for sure) that it would be superfluous.

I'm getting sublessness anxiety now. ;-)

Thanks Bub. I'm trying to get to listen to some ATCs. No luck so far. If I ever do & decide they're for me, I will definitely take that advice.


I think your spanky new 150s will cure that

 

[demotivated]

You did indeed.

I was just interested to see what if anything a Sub might add. I'm satisfied now that the H2s go low enough & there's nothing to be added from a Sub.

The other reason is I am toying with the idea of buying some Active Monitors (ATC, ADAM ???) & just wanted to understand the use of Subs. If I find a pair of Actives that I prefer to the H2s, but don't go as low (as seems likely), then I've got a plan..






GTM, you have an ability to explain things in a way a thick get like me, with minimal understanding, can understand. The bit a don't understand is that last bit, I've got them shoved hard against the back wall. Are you saying I need to raise the height?? I've heard the H2 has an equivalent 20" driver...is that true?? So how would I calculate the area/height needed? At the moment they are 40mm above the carpet & hard against the back wall.

There needs to be a little space where the sound exits and ideally bounces off the floor into a corner. The room corner = extra horn length and area. If the space is too little or too much the sound in the horn gets agrophobia or claustrophobia and most reflects back up the horn [impedance mismatch reflection] instead of out into the room.

 

[strummer]

I've moved the H2s into the corners. Sounding really good. Shouldn't work, they're 6.5M apart. I've pulled them about 6" out & they sound open, but with no loss of bass, which would happen if I moved them off the back wall.

I'll look into getting a wooden plinth & some longer adjustable spikes to have a play with the gap at the bottom. I'll start a new thread for Impulse H2 placement.

 

[Teddy Ray]

http://www.digido.com/articles-and-demos12/13-bob-katz/14-subwoofers.html

 

[GTM]

http://www.digido.com/articles-and-demos12/13-bob-katz/14-subwoofers.html

This statement is nonsensical :

"Play filtered pink noise (or the Mix CD's multifrequencies) at your best guess of crossover frequency, say 63 or 80 Hz."


Pink noise is by definition wideband in nature. It's not possible to play wideband noise at a specific given frequency. That would by definition be a tone.

I can only assume that it's meant to read:

Play pink noise (or the Mix CD's multifrequencies) through your system with your sub set at your best guess of crossover frequency, say 63 or 80 Hz.

 

[Pandapple]

This statement is nonsensical :

"Play filtered pink noise (or the Mix CD's multifrequencies) at your best guess of crossover frequency, say 63 or 80 Hz."

He does say filtered pink noise, which makes perfect sense.

63hz and 80hz are standard centre frequencys of 1/3 octave pink noise, and it is these test signals he refers to.

 

[Pandapple]

That kick that you're referring to, (presumably through PA systems) comes purely from the volume and the way the drum has been eq'd.

A kick drum obviously still gives a good thump all on its own though

I think most hifi enthusiasts never hear a kick drum, yet claim their system sounds like Live music...how does that work?

You can hear a kick drum just fine on 'ickle speakers, it doesn't disappear. (But sounding like live is cuckoo land... and as GMT points out, feeling the thump is all about SPL).

If you want, I can post spectral analysis of my own, raw recordings of a kick from a studio rock kit.

 

[Mr Ian]

In my long thin room I had terrible boom from H2s.

The only way i managed to cure it was to add an external crossover and pair of subs, diagonally opposite each other about 1/3 of the way down each long wall; equalise them individually via REW and a Behringer FBQ2496 and then run them in dual mono mode.

Not exactly "flat earth" but to me it sounds a hell of a lot better than it did running the H2s direct.

I am crossing over at 50hz because its the lowest option I have on the crossover but I suspect 40hz would have been better. Without the external crossover the Impulse H2s were falling away from 40Hz in my room at the listening position - about dead centre - probably the worse place I could sit

I also use the speakers for AV duties

graph is without any smoothing and I was aiming a reducing decay times and boom rather than a fully flat response