Axiom Home Page Forums General Discussion Technical Questions Graphs multiple subs multiple seats.

Ask and you shall receive.

The below graphs were taken using my Velodyne SMS-1 as the visual with no EQ adjustments in place. All speakers were calibrated to 73dB's from the Front Center seat. In addition, each sub was calibrated individually to 73dB's as well.

The EP600 was placed back up front centered below my screen and VP150. One 350v3 was placed along the shorter right side wall 6ft from the front wall. The second 350v3 was placed along the left wall about 16ft back next to my second row of seating.

Before I took the pitures, I played with different delay, phase, crossover settings before I found the best results from the main seat.

The pictures are in the following order from each seat; 600 only, 350's only, and finally all subs running. What I've found in all of this testing is that it is very difficult to satisfy all seats in the room, even with multiple subs, or EQ.



Front Center 600 only


Front Center 350s only


Front Center all subs


Front Left 600 only


Front Left 350s only


Front Left all subs


Front Right 600 only


Front Right 350s only


Front Right all subs


Rear Center 600 only


Rear Center 350s only


Rear Center all subs


Rear Left 600 only


Rear Left 350's only


Rear Left all subs


Rear Right 600 only


Rear Right 350s only


Rear Rigt all subs.

Randy,

Thanks for posting.

It appears that the 350s have the type of response that you would expect from a traditional subwoofer (unlike the DSP subs). If your room was smaller, the 350s would be adequate but because you have such a big room, there is no low frequency room gain and hence with just the 350s on, your bass response suffers below 35Hz or so. That's where the 600 comes in to save the day with its flat response down to 20Hz.

Looking at all your graphs, I don't see a compelling need for the 350s. Put the money towards a pre/pro and/or an A1400-8. Your daisy-chaining problems would go away too.

I dunno. Based on those graphs Randy is clearly getting smoother FR from multiple subs. The SMS graphical display is limited to 1/3 octave spacing so its not really as smooth as it looks. The null at 45hz with the 600 up front would make the single 600 sound anemic for front row seats during action flicks.

I would suggest using the natural rolloff of the 350s to your advantage and corner load the pair up front to boost low bass output and flatten that 45hz null, then either leave the 600 where it is or move it around until you find the best placement. One advantage of leaving the dual 350s up front is less problem with getting them in phase with each other and the mains. Its far easier dialling in one 600 as you move it around. If you can try to keep the 350s at an equal distance from where you are measuring and the 600 at a distance of the 350s less 3ft to get the time delay aligned between the 3 subs. The bass will sound tighter.

Randy,

You need to stay home for the next week and do some blind testing .

Jakeman,

Prior to last night, I did have the 350's up front spread out near my 80's per your original thoughts. This is when I had a terrible HUMP around 35-40 or so HZ, much worse than the null your seeing.

Which picture are you looking at, because the graph with all subs running from the primary seat looks pretty good me, the problem is you can't satisfy all seats in the room.

I tried moving the 600 around to various positions, with the 350's upfront in phase, but the graphs didn't seem to change much either.

I may try the 350's on the back wall spread out if I can figure out how to route the coax around the walk out door, see other thread.

Neener, Neener.... Randy's room sucks too!

Well guys, I've about had it with this stuff.

I don't know if I made a mistake getting the extra subs. Don't get me wrong they are great subs. It has to do with frequency response I'm suppose to see with multiple subs.

I don't know if the SMS-1 is not a true reflection of what is going on.

I don't know if the 350's are even helping at all.

I'm just frustrated as I have tried probably 20 different configurations, placements, phase settings, delay settings, you name it, this weekend and I'm not really impressed with any graphs I'm getting.

Placements tried:
600 up front, 350's spread out on back wall.
350's up front spread out, 600 on back wall.
600 on front wall, 350's on side wall.
I've also tried variations of the above 3 main locations, by sliding the subs in one direction or the other.

To me the graphs just don't seem to be getting better.

Should I assume that things are better, and the SMS-1 is not a true reading, like the ones Axiom uses in the videos?

Sorry, I'm venting, but I had high hopes that I would see some drastic improvements across all seating locations.

Randy, what do your ears and senses tell you? Forget the graphs and just go with that.

Oh yeah and I forgot to mention this dang buzzing I'm getting in all my speakers now, it is more pronounced in the center.

If I have just the EP600 plugged into the receiver sub out, no sound at all, all speakers dead quiet.

As soon as I plug the other subs, either daisy chained, or y-adapter at the receiver, buzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

Randy,

I'd bet my money on ground loops.

Send them back. That 600 is plenty for your room. And start enjoying your system .