EdwardJM: How about testing this classic sub: HSU TN1220 with dedicated 500 watt amp

Arthur S · 12-05-2004, 01:05 PM

Edward

The HSU TN 1220 is perhaps THE classic cylinder sub. It has been around for about 7 years and blew away the competition back in 1997. It has not been tested against any of the new high performance SVS cylinder models which it spawned.

HSU now has it for $1000 delivered with the dedicated 500 watt amp (42 pounds). This would make an interesting comparison to the new $1,000 Rocket UFW-12. Just how good is a $1000 sub?

HSU makes good stuff and doesn't get much "air time". How about checking this one out. The test by Don Keele in the old Audio magazine whetted my appetite. He got 101 DB at 12.5 Hz using a Crown Macro Reference (5000 watts?) but his review is not comparable to your current reviews.

I hope I can wet your appetite. This thing deserves another look.

Artie

Edward J M · 12-05-2004, 06:47 PM

Ask Dr. Hsu and John Johnson at Secrets if they would like it reviewed. If they both consent, you've got a deal.

I'm sure the TN1220 is a good performer; Poh Ser Hsu is one of the pioneers in modern high performance subwoofer design.

Rob Bird · 12-05-2004, 08:38 PM

Would you consider doing a comparo between the PB12-Plus/2 and the PC-Ultra? I'd really like to see those head to head with all the lovely measurements.

Edward J M · 12-06-2004, 05:41 AM

Quote:

Would you consider doing a comparo between the PB12-Plus/2 and the PC-Ultra?

Tom Vodhanel at SVS can provide you with the differences in clean output between these two models in the various states of tune. Suffice it to say, the PB2+ is certainly the stronger unit.

The Ultra has a unique sound quality and a lower native tune with all ports open; it would be my preference in any mid size room. In a large room for high playback levels, the PB2+ gets the nod.

Jason Dalton · 12-06-2004, 01:55 PM

Quote:

He got 101 DB at 12.5 Hz using a Crown Macro Reference (5000 watts?) but his review is not comparable to your current reviews.

Just an FYI, to drive that sub to 101dB @12.5Hz probably takes about 100W.

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GabeAJ · 12-06-2004, 02:52 PM

SVS also says that a pair of PC-Ultras will outgun a PB12-Ultra/2 from 20hz and below.

Edward J M · 12-06-2004, 04:09 PM

If you read Keele's review carefully, he measured a peak output of 101 dB @ 12.5 Hz with a 150 watt input and without respect to distortion. He measured 104 dB @ 16 Hz @ 22% distortion.

What's not clearly stated in the review is the forumula Keele uses to convert from 2 meter ground plane to the room. IIRC, he adds 6 dB to get the equivalent 1 meter ground plane value, and then he adds even more dB on top of that for room gain. I don't have the chart in front of me, but I think its around 8 dB at 20 Hz and progressively less as the frequency rises.

As we have discussed here before, there is not a hard and fast rule of outdoor to indoor gains. Keele has his formula, and he applies it equally to all speakers, so in that respect it is consistent. But some rooms are more lossy than others, and the distance to the subwoofer will vary greatly.

Designers like Mark Seaton have seen clean output levels DROP from the 2 meters ground plane figures when moving indoors if the room is large enough and the distance from the subwoofer is long enough.

Conversely, you can see an increase in the GP numbers when going indoors if the room is smaller and well built (rigid), and the distance to the sub is fairly close.

Just remember to compare apples to apples when quoting output figures and be sure to also state the circumstances and conditions under which the numbers were generated.

If I test the TN1220 (which might never even occur), it will be the straight numbers 2M GP for FR, THD, dynamic output, and power compression. I don't apply any type of formula to convert to an equivalent indoor reading.

I prefer to provide (c-weighted fast) SPL peaks at the listening position on DVD movies as a more useful real world indicator of indoor output capability in a mid-size room with the sub about 12 feet away.

Quote:

SVS also says that a pair of PC-Ultras will outgun a PB12-Ultra/2 from 20hz and below.

The PB12-Ultra/2 can hardly be considered weak at 20 Hz, but the dual Ultra's would probably outgun it by about 4 dB in clean output. More internal volume, way more port = no surprise. Dual co-located Ultra cylinders are the performance king of the SVS line-up way down deep.

The only thing that would make me give up my PB12-Ultra/2 is a pair of powered SS cylinders.

Arthur S · 12-06-2004, 06:10 PM

Edward, I am going to contact Po Ser Hsu and John Johnson and ask exactly what you stated: would they like the TN 1220 reviewed. I spoke to Dr. Hsu once and apparently he is not reluctant to speak on the phone. I have never spoken to John Johnson but I am more than willing to try to speak to him or write, if necessary. I own 2 SVS products but it would be a thrill for me to see the old war horse TN 1220 tested. Just reading about a $1,000 sub that could do 12.5 Hz, back in 1997, was a thrill.

Edward, you are probably going to kill me but I think you compared some apples to oranges in pulling some of your data from the Keele review. Keele did several different types of measurements. The 101 db @ 12.5 Hz was obtained in the maximum peak output (short term peak input) test. In this test he got 110 db at 16 Hz, not 104 db as stated in your last post. The only reason I know this is that I subscribed to Audio for many years and I have the August 1998 issue with the complete review. The condensed version available on the HSU web site does not include any of the graphs in the magazine. One particular graph includes peak output with room gain, peak output without room gain and peak input. The paragraph describing these findings reads:

With room gain, the maximum peak acoustic output starts with a very high 101db at 12.5 Hz, passes through 110db at 16 Hz, then rises to a local peak of 114db at 20Hz...dipping to 113db at 25 Hz...rising to 117.5db at 50Hz...

You are correct though about the peak input at 12.5 Hz. It was 150 watts, rising to 660 watts at 16 Hz and 1,350 watts at 20 Hz.

Edward, I hope you are not put off by this additional information. You have joined a small group of professionals who have the privilege of testing subs for those of us who love them but don't have the expertise, the equipment, and the muscle power (to get these monsters outside and back in again), to conduct such tests. I have some stuff for you to add to your collection. I will be in touch.

Thanks

Artie

Edward J M · 12-07-2004, 03:14 AM

Quote:

Edward, you are probably going to kill me but I think you compared some apples to oranges in pulling some of your data from the Keele review. Keele did several different types of measurements. The 101 db @ 12.5 Hz was obtained in the maximum peak output (short term peak input) test. In this test he got 110 db at 16 Hz, not 104 db as stated in your last post.

Hi Arthur:

I'm not put off at all, don't worry about it.

My point was the 101 dB at 12.5 Hz (and all the rest of the maximum output figures) were conducted without respect to distortion. And (as far as I can tell) also included Keele's formula for room gain.

So simply stating (as you did in your first post) that a given sub pulled 101 dB @ 12.5 Hz without any other frame of reference or context can be misleading.

I included the 104 dB @ 16 Hz @ 22% distortion figure in comparison only, and I realize the two test parameters were completely different.

I see from PM you will be sending me a copy of the review (thanks). The best thing in the interim would be for you to post the straight 2 meter ground plane numbers for: 1) maximum peak output and 2) steady state output with distortion included. Make sure they are not the 1 meter equivalent numbers, which would have 6 dB added.

Good luck in your conversations with John Johnson and Poh Ser Hsu.

Regards,

Ed