SVS PC13 Ultra

That would have kinda pointless, as my friend and I both new which sub was turned on during the test. Suffice to say the difference was very noticeable to both of us in his room. I do concede it was only 1 room, but 3 AVF members who swapped after reading my write up all agreed.

FYI, the reason for the testing was because of the following.

I had a PB Ultra and was giving setup advice to fellow forum members. Nothing seemed to cure the issues they had with their cylinders and I couldnt replicate them in my room with my box. During this time a friend demo'd my sub as he was buying a new one. He ordered a cylinder because of its smaller footprint. Once his sub arrived he couldnt get it just right and was reporting the issue other members had with chuffing and grill noise. So, I took my laptop down to his house to set his sub up for him. I spent 8 hourse moving the sub around, running graphs, re-running Audyssey on his amp and trying to get it right. I did improve it a vast amount but we still couldnt completely cure the issues and it didnt sound as good as my box did in my room. At the end of that session the only conclusion we came to was that we had to do a direct side by side shootout to rule out the sub design as the issue.

The following week I took my sub to his house and we spent another 6 hours on the shootout. The end of that brought us to the conclusion the design of the box was indeed superior as the differences between his house and mine remained. The box sounded more accurate, articulate and its quality just seemed a step up.

I came to the following conclusions about the box vs cylinder.

The cylinder suffers from artefacts in the audio due to the drivers location to the bass plate. Both subs when driven hard (near the drivers limits) made a kind of clacking sound. On the box you could only hear this when the speakers were disconnected, but the with the cylinder the proximity of the bass plate seemed to amplify this to the point where you could hear it over the main speakers, and at lower volumes. This was never an issue with the box as you could never normally hear it, and the cylinder seemed to make this audible at lower levels that were within normal listening levels.

The driver seems to operate a bit tighter in the box, in that the bass sounds tighter, like the driver can start and stop quicker. On the cylinder it seemed overblown compared to the box, like distortion was creeping in. I guessed a bit at this, but one theory I thought about was that due to the box's design, perhaps there was more pressure inside the box helping with driver accuracy, more in line with how a sealed box would work.

Chuffing came in sooner on the cylinder, and again well within my friends normal listening levels. The box didnt chuff at all, even in 10hz mode, untill I put the sonic boom scene on from Iron man, put the amp at reference level, and upped the bass channel from -6 to +5. This caused the box to finally chuff, but only in 10hz tune. My theory on this is that the ports bend inside the box, and sit a 90 degrees to the back of the driver. In the cylinder they are dead straight and sit face on to the back of the driver. The box also has more wadding inside between the rear of the driver and the port inlet. To me this basically meant the velocity of air in the ports is faster on the cylinder, and this leads to chuffing coming in sooner.

The last issue I found/had, was the grill on the cylinder. Audible noise from the air being forced through the holes in the grill was very apparent from moderate to high levels. This simply never ever happened with the box. One reason for this IMO is the apparent increased air velocity from the ports, but this isnt the main reason. The grill on the cylinder is fixed above the ports in a small area. This area inside the grill and between the ports is a sealed area, so all the air from the ports is forced through the grill. On top of this, the small area and the fact its sealed means the grill resists the air a bit, increasing the pressure and velocity if the air being forced through the grill. On the box, the top of the grill is open so there is no pressure build up, and the grill is larger so there are more holes for the port wind to travel through. This means on the box there is basically never any grill noise at any level that you can hear.

One last advantage of the box we found was with port resonance. We concluded that both sub had the occasional port resonance sound with certain material, but the box seemed to mask it a bit better. I think the fact the driver is sat right over the ports helps mask these sounds, but with the cylinder, the noise seemed a little easier to detect, perhaps because the ports are away from the driver.

To sum up, there are things that are noticeable with both subs but that the box seemed to hide better, but in any case these small issues didnt really give any cause for concern with either design. The main issue was the cylinder seemed boomier, chuffed earlier than the box (and noticeably sooner) and suffered from grill noise caused by the air rushing through the grill holes.

Not all people report the issue though, so we came to the conclusion certain rooms must make the issue more apparent. Perhaps when setting up for reference volumes and flat responses, certain rooms push the sub harder for the same perceived output causing the issues. That said in our side by side test the box performed better, which leads us to conclude the box is still the better of the 2 designs.

As a result I tend to push people to the box if they are choosing between the 2 designs now, but the cylinder is still a great sub that cant be bettered for the money, at least here in the UK. Its not that the cylinder is a bad sub, just that IMHO the box is enough better to justify is higher price tag.

I do have plans to visit another cylinder owner in the near future, one who reports no issues with his cylinder. I'm hoping to find his sub sounds as good as my box, and a final conclusion will be possible from that.

Cheers