SVS PB10-ISD Independant Review

[tpg]

I did not read the other review, I don't think... But, the FR of a sub will be heavily dependent on the room, and how careful the tester is in testing. Some might just run a 100Hz-20Hz sweep if they are lazy. Others might go down in small increments to get pretty close to the exact response. Mostly, though, it could be/probably is room difference.

[yromj]

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On 10/29/2004 10:15:48 AM tpg wrote:

I did not read the other review, I don't think... But, the FR of a sub will be heavily dependent on the room, and how careful the tester is in testing. Some might just run a 100Hz-20Hz sweep if they are lazy. Others might go down in small increments to get pretty close to the exact response. Mostly, though, it could be/probably is room difference.

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In the reveiw I linked to, the reviewer did his testing outside, thus eliminating room effects.

John

[Orange Peel]

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On 10/29/2004 12:07:36 AM tpg wrote:

This is true... it does probably best anything in its price range.

It is quieter in my room now... and I can think again. Van Halen has a lot of loud kick drum stuff going on, and my sub is about two feet from me when I am on the comp listening to music. So... all my thoughts were a little skewed earlier with all that going on. Nothing I wrote earlier made much sense. heh Sorry about that...

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It's ok, I forgive you I know what a lot of bass can do to a mind, nothing is right immediately following it If you ever get to hear this sub, I would highly recommend it, it's crazy how a $400 sub can do what that thing can do!!

[xcjago]

After doing some more research, I don't think COF's review should be considered the "holy grail" review of the PB10.

It turns out that he is a HUGE fan of Sunfire, and considers them to be THE best subwoofers. Take a look at the following review or pretty much any other review of the Sunfire MKII:

http://www.hometheaterhifi.com/volume_4_4/sunfiresubmk2.html

As you can see, there is HUGE dropoff after 25hz.

Next, COF never mentions THD measurements for Sunfire. Why? Maybe because of this:

http://personal.inet.fi/private/ilkka/scans/6_7_1998_1.jpg

Notice that the THD exceeds 30% at 20hz. In the PB10 review he measured the PB10 at only 5% distortion at the same settings.

Here are Ed's comments on this graph:

These 3D spectral decay plots are far more revealing of what is happening with the subwoofer enclosure and resonators than the more common 2D impulse response (voltage vs. time) or decay (amplitude vs. time).

This is very typical performance for Sunfire:

1) Extension to the mid 20 Hz region with a sharp drop-off.

2) High distortion at 100 dB, averaging 20% (!) from 35-25 Hz, and then quickly rising to over 30% (!!) below 23 Hz. This is why some people like the "full bodied" and "complex" sound of the Sunfire - lots of audible distortion harmonics being created at low frequencies.

3) The resonance you pointed out at 23 Hz is likely the passive radiators resonating at their tuning frequency. Note the resonance at 23 Hz overwhelms all the other resonances, with much lower amplitude resonances being seen at 100 Hz (or even higher) in the 30-60 ms bandwidth.

4) The 16 ms of group delay at 31.5 Hz is not audible based on available research here in the states. I would expect group delay on the Sunfire to be the highest just below the tuning point of the PRs. Do you have any additional research on the audibility of group delay in the 20-50 Hz bandwidth?

Also typical is the Velo performance, with THD being held to 3-5% by the servo circuitry - a nice performance.

Nice graphs, Ilkka, many thanks.

Ed

In a similar discussion on the Sound and Visions forum Tom V. posted this in comparison of Sunfire and SVS subs:

btw, for those interested you can see measured THD comparisons between some of the design types being discussed....

All the way at the bottom of this link, they have a $1499 MSRP "small cube".

http://www.hometheaterhifi.com/volume_9_2/svs-cs-ultra-subwoofers-5-2002-part-2.html

47% THD, 20hz...98.5dB

The SVS in the same review has <5% THD at 100dB with the same 20hz signal.

That is about 1/10th the distortion.

So every design has its advantages and disadvantages. SVs tend to be large and they won't fit into some decors. But you are definitely trading off clean output capabilities with the tiny cubes...there is no getting around the laws of physics. When someone figures that out...they sure wouldn't be building a audio speaker with the secret..

The key is to decide which trade offs work best for your situation and then govern your purchase decisions accordingly.

Tom V.

SVS

and this:

I don't know of too many radio shack subs that are small cubes with "very powerful amps" and a $1299 msrp.. You can try emailing John Johnson(the reviewer in question) to ask him more about sub *X*...but it is one of the models in discussion in this thread.

You can also look into the Don Keele reivews to see how small cubes compare to larger enclosures from a price/output/distortion ratio. The small cubes are great...when that is all you can fit into the decor. They cannot...can NOT compare to the clean output capabilities of a larger enclosure. This has been documented in various tests repeatedly, over the past decade.

At the end, COF admitted that Tom was correct, and that the main reason he considers Sunfire to be better is because they are smaller.

COF -

I prefer very large enclosures. In fact, my favorite subs have all been infinite baffle systems with lots of very large drivers and tons of power.

This is a very sticky argument to have. All subs have advantages and weaknesses. To acheive the best performance, a large enclosure is pretty important. Most people do not want a fridge in their HT just for the sub, nor are most people willing to cut huge holes in their floors or ceilings to mount four 18" woofers for I.B. sub.

My praise of the Sunfire sub is based on the assumption that most people want the smallest possible enclosure to meet their significant other's requirements for room decor.

Wab - the sunfire sub has one driver and a passive radiator. That is very different from two drivers. Also, the pressures inside the cabinet are massively huge. Larger enclosures don't have these pressure levels.

By the way - Tom knows a hell of a lot more than me about the current subwoofer market and design philosophies. I haven't done this for a living in over ten years. He is doing it today.