Trouble getting good response for 2 people

marty1

Active Member
I'm back to trying to perfect my subs response AGAIN! :blush:

I get a fairly good response from my listening position but my wife sitting next to me has drawn the short straw, naturally as it's my stuff :thumbsup:

I would like to try and get her hearing good quality bass but no matter where I move the sub one of us always loses out, mainly due to huge dips being present making it almost sound like there is no sub at all. Is there something else I could try or is the only sollution to add a second pb13u placed between the centre and right speaker? (the sub is currently between the centre and left speaker, about 3 feet from corner and 6 inches from front wall)

I have noticed that thx recommend sub should be placed in the middle of the front wall, I have never heard of anyone on hear placing their sub there, but that would put it inbetween us, would that work? The problem is I dont think it would be ideal to use the sub as a centre speaker stand :rolleyes:

Any ideas?

Thanks in advance
 

Member 639844

Former Advertiser
A second sub would be the best option, and yes, I have tried a sub up front and it worked very well. My cerrent sub is just behind my front right speaker.
 

marty1

Active Member
A second sub would be the best option, and yes, I have tried a sub up front and it worked very well. My cerrent sub is just behind my front right speaker.

It was a nightmare pulling up the floorboards and carpet to run the cable from my av equipment at the back of the room to my sub and speakers at the front, is it possible to run a sub cable out of sub to the other so I still only have the one cable coming from the amp?

Also is there a chance that 2 pb13s could unbalance the sound so I loose my fairly good response I have got from my position at the mo?

What is your take on thx central sub placement (underneath centre speaker)?

Thanks
Marty
 

Member 639844

Former Advertiser
The THX specification is based on a complete THX setup, including the room. In any other kind of room, the sub could go anywhere and is determined by its response. A second sub will likely fill in any dips, but again you need to determine where it needs to go in order to fill in any dips. This could be at the front or another position, you need to work it out. Any unbalance will come in the form of peaks, which any auto eq solution will be able to tackle fairly well.

As for cables, daisy chaining subs is fine and most commercial subs have an output by which to do this.
 

marty1

Active Member
That sounds good to me, no pulling the carpet up again :thumbsup:

I thought dips are worse than peaks, as you cant do much with them, also they make the sub sound lifeless, at least with peaks you can still feel the subs power, when I had a monolith in my old flat I found that in the front corner postion between the centre and front right speaker I could turn the subwoofer volume dial up full and barely hear the sub at all, it was terrible!!
 

Member 639844

Former Advertiser
Both dips and peaks are detrimental to the accuracy of the bass reproduction. Minor dips will go unnoticed until you you once again have those frequencies returned. Major dips lead to the effect you describe. Major peaks will lead to a focus on the frequencies which are boosted. The resulting effect of this is dependant on the particular frequency or frequencies boosted. Higher up the range, such peaks will lead to a boomy sound which the more experienced will notice immediately. Lower in the frequency range its less of an issue, especially below 20hz which the ear is much less sensitive to the sound.

The reason a second sub will help with dips is nicely illustrated in a build thread of my own here. In it you can see the individual sub responses, and how a dip in one subs response it resolved by the second subs different response due to being in a different location within my room. The end result is a pretty darn flat overall response. This is the only truly effective way of countering serious dips in response, especially true nulls which will never be boosted out.
 

marty1

Active Member
That looks great to me!

Are those responses with 1/3 smoothing? Since chatting to bpape on the other forums I dont use any smoothing but it is so hard to get a decent looking line :(

Here is my current response with 1/3 smoothing and without, to look at one it looks like a great response to me, then I look at the other and go OH DEAR! A lot of work to do!

What do you think?
 

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Member 639844

Former Advertiser
I always use the smoothing. The main reason is that its more indicative of how your ears actually hear the response. Super accurate responses with marginal spikes look worse but they are more accurate technically speaking. The issue for me personally is that you cant hear it like that, and the smoothed graph (which is less smooth than all the auto eq produced graphs anyway) gives a better look of the overall response. Add to that you have to stop somewhere and the smoothed graph helps with that. You will never get a flat graph with no smoothing at all, and the smoothed graph helps determine when you have found a good place to stop.

Peoples opinions differ, but thats mine.
 
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marty1

Active Member
The issue for me personally is that you can hear it like that, and the smoothed graph (which is less smooth than all the auto eq produced graphs anyway) gives a better look of the overall response.

Sorry did you mean the issue for you is that you cant hear it like or can hear it the way it looks without smoothing?

Does my response I attached look problematic or good? I have only tested my wifes listening position without smoothing so maybe it might not be so bad after all.
 

marty1

Active Member
What I do find is that with this response the bass isn't overbearing but in scenes like the star trek warp jump, when I give a demo to my mates, I sit along the side wall couch and the bass thumps you hard in the stomach, it feels and sounds great, but when I sit in my main listening position (the above measured response) it doesn't have the thump that I like, it sounds good but lacking in power. I did measure the side wall response and it was all over the place, even with smoothing, the only thing I did notice was it goes a bit higher around 50hz, so maybe that is where the thump is?
 

Member 639844

Former Advertiser
The SVS when sealed is a lower Q sound, which robs systems of that punch when it drops to around .5, as the SVS does. This sound character carries over when you unseal the sub and can even go less punchy as the low end comes up even more. Its undoubtedly the increased 50hz zone bringing in that punch and large low tuned cabinets, when eq'd flat or close to, tend to have less of that punch. Adding in a second sub will increase the punch a touch, and loosing any dips will also help, but to really get that punch in, you would need to apply some manual eq to boost the upper sub bass zone, if thats what you wanted.


Sorry did you mean the issue for you is that you cant hear it like or can hear it the way it looks without smoothing?

Does my response I attached look problematic or good? I have only tested my wifes listening position without smoothing so maybe it might not be so bad after all.
I meant cant. Your ears struggle to pick up in minor dips and peaks that start and stop at frequencies very close to each other. Your smoothed graph looks good, but the un-smoothed less so. I would probably try improve the raw response a little but if you cant you cant. The idea is to get it as good as you can, not perfect, as thats almost impossible.
 
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marty1

Active Member
The SVS when sealed is a lower Q sound, which robs systems of that punch when it drops to around .5, as the SVS does. This sound character carries over when you unseal the sub and can even go less punchy as the low end comes up even more. Its undoubtedly the increased 50hz zone bringing in that punch and large low tuned cabinets, when eq'd flat or close to, tend to have less of that punch. Adding in a second sub will increase the punch a touch, and loosing any dips will also help, but to really get that punch in, you would need to apply some manual eq to boost the upper sub bass zone, if thats what you wanted.



I meant cant. Your ears struggle to pick up in minor dips and peaks that start and stop at frequencies very close to each other. Your smoothed graph looks good, but the un-smoothed less so. I would probably try improve the raw response a little but if you cant you cant. The idea is to get it as good as you can, not perfect, as thats almost impossible.

You say try and improve the raw response but doesn't the fact that the smoothed response looks good then that is pretty much what my ears can hear?

Also when you say boost the upper bass zone do you mean say 100hz and up?
 

Member 639844

Former Advertiser
The unsmoothed response could be a little better. It shows some deviation that is a little more than simple spikes and sharp dips. The smoothing does hide those a bit and any peaks or dips that cover a broader range of more than +/- 5db are ones I personally would try to tackle. Audyssey would do this and you auto eq solution should help with that. Its true the smoothed response is a little more indicative of what your really hear, but like I say, broader peaks and dips are something I would try improve if I could. I would personally consider anything from about 40hz and up the upper sub bass zone, because you can hear this quite well, and its that area that will provide punch.
 

marty1

Active Member
The unsmoothed response could be a little better. It shows some deviation that is a little more than simple spikes and sharp dips. The smoothing does hide those a bit and any peaks or dips that cover a broader range of more than +/- 5db are ones I personally would try to tackle. Audyssey would do this and you auto eq solution should help with that. Its true the smoothed response is a little more indicative of what your really hear, but like I say, broader peaks and dips are something I would try improve if I could. I would personally consider anything from about 40hz and up the upper sub bass zone, because you can hear this quite well, and its that area that will provide punch.

Ok looks like its back to the drawing board, another svs will be on the cards but I would like to get the punch in my setup, whats the auto eq? Do you mean the amps auto eq like I have mcaac?
 

Member 639844

Former Advertiser
I am not familiar with the exact specifications of the MCACC Pioneer use, but ye thats what I am talking about. IIRC, and dont quote me, it does implement some basic PEQs to help eq the sub(s), but I am not certain how effective it is compared to something like Audyssey room correction that I use.

Its worth noting that adding in a second sub will change how the subs sound. Your effectively halving the size of the room the sub sees and that helps increase punch because of how room gain acts on the subs response.

With the multi sub setup, do you have any particular spots planned, or do you have a few available. The only way your really going to improve the response is by locating the subs separately. The way forward is to identify the best spots for the subs, use the spl to balance them, then use REW to set the phase and implement the PEQ's on the subs to smooth any peaks. Then complete the setup using the auto eq. The good thing about the SVS subs is that they have PEQ's on board, so even if your room correction is pretty simple, the subs themselves will give all the help they can. The do have a lot of options though, and selecting the best tune for your setup will give you even more to do.

Only question though, is that the new Ultras are a slightly different design to the old ones, have you figured that into the equation.
 

marty1

Active Member
I am not familiar with the exact specifications of the MCACC Pioneer use, but ye thats what I am talking about. IIRC, and dont quote me, it does implement some basic PEQs to help eq the sub(s), but I am not certain how effective it is compared to something like Audyssey room correction that I use.

Its worth noting that adding in a second sub will change how the subs sound. Your effectively halving the size of the room the sub sees and that helps increase punch because of how room gain acts on the subs response.

With the multi sub setup, do you have any particular spots planned, or do you have a few available. The only way your really going to improve the response is by locating the subs separately. The way forward is to identify the best spots for the subs, use the spl to balance them, then use REW to set the phase and implement the PEQ's on the subs to smooth any peaks. Then complete the setup using the auto eq. The good thing about the SVS subs is that they have PEQ's on board, so even if your room correction is pretty simple, the subs themselves will give all the help they can. The do have a lot of options though, and selecting the best tune for your setup will give you even more to do.

Only question though, is that the new Ultras are a slightly different design to the old ones, have you figured that into the equation.

No I hadn't accounted for that :rolleyes: I will have to look into it, I am sure they will be similar performance?

I have 3 spots for the subs apart from the non practical middle of the floor area, the spaces on both sides of the centre speaker in between the left and right mains and behind the couch in the corner.

Is there a quick way to identify the best positions, or at least a quicker way of finding a good starting point because it seems to me inches can make a big difference, not only moving the sub but also the couch because I can imaging getting 2 responses to be good must be even more difficult.
 

Member 639844

Former Advertiser
I would have expected performance to be very similar, but I would consult with SVS for that.

As you have 3 positions available, simply measure a single subs response in each position, and overlay the individual responses. From that, you need to identify 2 which look to work together well. By that, look for 2 responses where the dips they have are countered by the response of the other sub. This will have the effect of removing the dips when the subs are played together. Any resulting peaks are easily tackled by room correction software.

The difficult, or rather, more complex element, is that the Ultras afford a lot of options when it comes to choosing the tuning modes, phase, and PEQ application. This will be further complicated with the new sub, which no longer has the ten hz tune and has and extra PEQ band IIRC.
 

marty1

Active Member
I would have expected performance to be very similar, but I would consult with SVS for that.

As you have 3 positions available, simply measure a single subs response in each position, and overlay the individual responses. From that, you need to identify 2 which look to work together well. By that, look for 2 responses where the dips they have are countered by the response of the other sub. This will have the effect of removing the dips when the subs are played together. Any resulting peaks are easily tackled by room correction software.

The difficult, or rather, more complex element, is that the Ultras afford a lot of options when it comes to choosing the tuning modes, phase, and PEQ application. This will be further complicated with the new sub, which no longer has the ten hz tune and has and extra PEQ band IIRC.

The thing I am concerned about is that once 2 subs are playing similtaneous could they clash and cancel out some frequencies?

Just jumping in with a another question about my measurements, any dips above 100hz would be my floorstanders issue correct? I have always been advised to keep them away from walls as the bass gets enhanced but in order to pick up that dip is pushing them closer to the wall the best thing to bring those dips?

Sorry to sway off topic (you know what I'm like :()
 

Member 639844

Former Advertiser
The thing I am concerned about is that once 2 subs are playing similtaneous could they clash and cancel out some frequencies?

This is what REW is for. It is a possibility, but the variable phase on the subs will help iron out such issues.

Just jumping in with a another question about my measurements, any dips above 100hz would be my floorstanders issue correct? I have always been advised to keep them away from walls as the bass gets enhanced but in order to pick up that dip is pushing them closer to the wall the best thing to bring those dips?

Sorry to sway off topic (you know what I'm like :()

The LPF on the subs rolls off its response from 80hz (assuming you set it to 80hz of course) and therefore can effect frequencies quite a bit higher up the range. You should also really have the LFE set to 120hz for the true correct setting, so the potential for the sub to effect frequencies can go much higher than 80hz.

You can place speaker closer to walls to boost their bass performance and augment their response if you wish, and again, you can use REW to play with their placement and find something that works best for you.

When you get your second sub, I can help more with dual sub setup and go into more detail then if you need the help.
 

marty1

Active Member
This is what REW is for. It is a possibility, but the variable phase on the subs will help iron out such issues.



The LPF on the subs rolls off its response from 80hz (assuming you set it to 80hz of course) and therefore can effect frequencies quite a bit higher up the range. You should also really have the LFE set to 120hz for the true correct setting, so the potential for the sub to effect frequencies can go much higher than 80hz.

You can place speaker closer to walls to boost their bass performance and augment their response if you wish, and again, you can use REW to play with their placement and find something that works best for you.

When you get your second sub, I can help more with dual sub setup and go into more detail then if you need the help.

Thanks :thumbsup:

I am pretty sure that the pioneer LX72 does not have LFE settings, just large and small for each speaker and then crossover freq which I set to 80hz.

I am not sure what is causing the problem but above 100 hz is very problematic, the mains were originally about 2 feet from the corners but the dip was huge across the 100-200hz range. I pushed them into the corners and on the 1/3 smoothing it looks okay but still problematic.
 

Member 639844

Former Advertiser
Thanks :thumbsup:

I am pretty sure that the pioneer LX72 does not have LFE settings, just large and small for each speaker and then crossover freq which I set to 80hz.
Large and small would be for the speakers, which I would take to mean the crossover setting to mean its the LFE control, not a second speaker setting. Seems a little inconclusive, doesnt your manual clarify this?

I am not sure what is causing the problem but above 100 hz is very problematic, the mains were originally about 2 feet from the corners but the dip was huge across the 100-200hz range. I pushed them into the corners and on the 1/3 smoothing it looks okay but still problematic.

Have your tried running the system without the sub and setting speakers to large, then measuring each single speaker alone. The comparison might be educational and even shed some light on things. There is a whole heap of things you can do to try identify the root cause of issues if you really want to dig and try resolve things. An SVS Ultra with speakers that are weak in the 100-200 hz range would leave a system missing something for me personally too.

Your system sounds like an interesting challenge, shame we arent closer, I would be interested to come have a play.
 

marty1

Active Member
Large and small would be for the speakers, which I would take to mean the crossover setting to mean its the LFE control, not a second speaker setting. Seems a little inconclusive, doesnt your manual clarify this?



Have your tried running the system without the sub and setting speakers to large, then measuring each single speaker alone. The comparison might be educational and even shed some light on things. There is a whole heap of things you can do to try identify the root cause of issues if you really want to dig and try resolve things. An SVS Ultra with speakers that are weak in the 100-200 hz range would leave a system missing something for me personally too.

Your system sounds like an interesting challenge, shame we arent closer, I would be interested to come have a play.

Well if you are ever up for a working lunch and paid travel expenses to Dagenham you are more than welcome to pop in, I'd appreciate the help :thumbsup:

I will try and measure the speakers without sub when my wife is out cleaning the rabbits this week. I think the focal profiles are quite capable speakers so should have no problem picking up where the sub leaves off.

In regards to the amp settings the yamaha I used to have was the same, you can only select 1 crossover frequency for all speakers similtaneously, the only thing you can do with speakers is set them to large or small.
 

marty1

Active Member
Before I measure I just wanted to check, does the spl and soundcard calibration files actually have get counted into the end result?

I have only ever seen the trace lines for them on the end result, I dont see it actually changing the measurement line?
 

Member 639844

Former Advertiser
If you look in the settings area in REW, it will tell you if there are files loaded in for the sound card and spl meter. If they are then they are counted in any and all measurements taken. IIRC, you can switch the lines for the SC cal and target response on and off.
 

marty1

Active Member
If you look in the settings area in REW, it will tell you if there are files loaded in for the sound card and spl meter. If they are then they are counted in any and all measurements taken. IIRC, you can switch the lines for the SC cal and target response on and off.

Do you mean the little boxes at the bottom of the graph where you can tick or untick the box?
 

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