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Do I need to go down to 20hz?

3371 Views 50 Replies 28 Participants Last post by  Ddavidson
I haven't decided on a sub yet, but it will probably come down to SVS or HSU. I like the SVS 20-39pci but the wife may object to the size. I also like the HSU STF-2 for the size and price, the wife would prefer this one also. The STF-2 is tuned to 25hz while the SVS 20-39 is tuned to 20hz., Will the extra 5hz make much of a difference, will I notice it? It will be used for probably 75% movies/tv. My room is about 14'x12' and we won't be pushing a lot of volume.


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I wish I could say that I've listened to these side by side, but I can't.

I can tell you this - I recently got an HSU STF-2, and my room is very similar in size to yours. I love it!

Also, HSU is known as being honest and conservative in their #'s. The STF-2 has usable bass below 25hz, it's just not flat. My guess is that you would not hear a very big difference between the two.

I made my choice to go with the HSU b/c I live in Calif, so the shipping was cheaper and faster. This might seem like a silly reason to make a decision, but that's what it had to come down to. They are both great products and I had to pull a straw.

You mentioned that you like the HSU for size, price and WAF. It sounds like that would be the way to go. I doubt that the SVS would give you any amount of increased performance that could make up for those three factors.



PS - Again, I have not demo'd an SVS and I think it's a great company with a great product. I'm just offering an endorsement for HSU to help our friend make a decision :)
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I have read multiple threads on SVS vs. HSU and they all say that with either one, you will not be disappointed. I think I'm starting to lean towards the HSU due to the price/size/WAF.


Originally posted by jds22
I Will the extra 5hz make much of a difference, will I notice it? It will be used for probably 75% movies/tv. My room is about 14'x12' and we won't be pushing a lot of volume.



There isn't a whole lot of movie info at that level (20-25hz) anyways.

The subs are tuned to that frequency. This means that due to the port and box design there will be a increase in output at that frequency. While output below that frequecy will drop off, you will still have some output at frequencies below the tunning frequency.
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25Hz is pretty low. Low enough IMO. You might also want to consider the new Outlaw LFM-1. Form factor is close to the HSU (who helped with the design.) From outlawaudio.com :

Model LFM-1 Specifications [partial]

Amplifier Power Rating: 325WRMS; 1300W peak

Frequency Response: 25Hz. -180Hz. +/- 2 dB

SPL: 115dB (subject to placement and room gain)

Dimensions: (HxWxD) 21.75†x 15.0†x 22.0â€

Weight: 58 lbs
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I'll throw in my vote for the SVS. I've had a 20-39PCi since June 03. Over the weekend I had the opportunity to calibrate a system using a HSU VTF-2 (I realize this isn't a direct comparison because you are referring to the STF-2). While I found the HSU absolutely flawless in music reproduction I didn't care for it as much in terms of home theater. It just didn't have the output or extension to match the 20-39. On the other hand, you are talking about quite a difference in price range. I believe the HSU runs around $400 and the SVS runs $600.

I would have zero problems recommending the HSU. It did exactly what it claimed to do and did it flawlessly. It just isn't what I want from a sub. After having a sub that will deliver well below 25Hz, and knowing what is down there, I couldn't have a sub that left it out.
20hz test tones and pipe organ are fun for impressing your friends or making the beams rattle. Do you need to impress your friends or make the beams rattle? 95%+ of movie bass effects are 25hz and above.

So the question becomes do you want to hear 95% or 100% of those movies?
well i have a pb2+. it came factory tuned at 25hz, I listened casually to that for a while. then I put in the port blocker, and it was then tuned to 20hz. I seriously couldnt tell a difference. I'm sure there's more extension and stuff down to 20hz, so i just left it in there. IMO, I dont think its how low the sub goes, but how loud it is. Everyone is very impressed with the fact that its so loud, noone commented on how it was "deeper' than their subs. I still have one port blocker left, and I could tune it to 16hz, but i hardly see the point.
Hmmm, it kind of sounds like if I got the HSU, I would be perfectly content as long as I don't go stand next to the SVS 20-39. I have never heard a good, low sub so I wouldn't know what I was missing unless I heard it. I'll have to show the wife the pics of the SVS again. With some of the packing supplies I have around my office, I could proabably make something about the same size as the SVS and put it in the living room and see how it fits.


i never really had a good, low sub until the SVS either. I had a Bose am 10, and a Klipsch Promedia 5.1, which is descent in its own right. I guess I still dont know what good/bad bass is. I can assume from the reviews that SVS is good bass, and if I bring other subs into the house, then i'll know what is bad bass. in any case, i consider myself to be very keep in intuitive, and if i didnt pick up on the tuning difference, you might not either, only crazy bassheads will.
Do I need to go down to 20hz?
Well, the simple answer is 'No'.....but the HT enthusiast answer is a resounding 'Yes'.

Going down to 20 hz is one of those ideals crossed off the list when going for the ideal surround environment..Though one is ub is rated at 20 hz and the other's at 25 hz, it really doesn't mean anything as they are manufacturer specs and your set up, room will vary things.

Most subs will give some 25 frequencies but the real question is what is the output at that level???? Or is it 6 or 10 db below calibration level. IF so, it really doesn't count.

That said, there is no way to tell what sub will do what in your room at 20 - 25 hz without testing them out........

That said, if HT is 75% buy the beefiest sub you can afford and odds are you will get down into that power house frequency level of 20-25 hz (or below).
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I don't know if this helps, but I have the 20-39pc+ in 22x22x9 room. I placed one of the port blockers in to tune the sub down to 16hz. Not too long ago, I pulled the blocker out, just to see again if I liked it more with or without. What happened is I lost much of the bass you feel, not the bass you hear. The blocker went right back in.

For me, that's the wow factor in our HT. Not that many movies go that low, but when they do... I didn't notice a difference in music performance with the blocker in or out.

Now, it may be the vagaries of my room, setup, etc. But with the $$ I've spent, I want to have that extra oomph. I don't need it, but when you're talking HT, we really don't need any of it.
I sit 18ft away from both of my dual 20-39PC+'s, with the latest releases on dvd's I have been surprised by the subsonic material that are on these movies as of late. Has anyone notice this or is it just me?
If you desire lower extension and waf is a concern, get the STF-3 for $600. This sub is close to the VTF-3 in performance. Read some of the STF-3 review on the Hsu-centric forum. Some of them have owned the VTF-2, and notice a huge improvement in maximum output levels and low frequency response extension. We are talking true 20Hz frequency response with the STF-3, and much more output because of the nice 12 inch driver and more amp power and box size.

The VTF-2, with it's smaller size and tuned to 25Hz, will obviously not play as low and as loud as a much larger (and more expensive) sub tuned to 20Hz. Above 25Hz it does quite well, but still not nearly as good as a STF-3 or VTF-3 when really pushed in a very large room. For it's size and peformance for the $, it does extremely well. However, your room is not so humongous, and the STF-2 or VTF-2 would fill it well.

The STF-2 is really a little bit more capable than the current and older VTF-2 with one port plugged. It has more port diameter, newest tech and driver, and more amp power.

With the increased budget, the Outlaw looks to be a good deal too. Rumor has it that Dr. Hsu helped design that product. There is also a sub from ADIRE that is lower tuned and available in the $600 range. Even a VTF-3 MKII available in black finish is going for $699 (free ship) next month. Generally more options open up as price increases, but for $399 there are two standouts, ADIRE and Hsu.
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Originally posted by Terence
I sit 18ft away from both of my dual 20-39PC+'s, with the latest releases on dvd's I have been surprised by the subsonic material that are on these movies as of late. Has anyone notice the this or is it just me?
Yes, more and more movies are coming out with great subsonic bass. The movie producers began to realize that it could be a great selling point for DVD releases.
Have to agree with Markotran on the $400 models.

I think the SVS 20-39PCi is in a different league than the STF-2. With over a $300 price difference you really sb looking at the STF-3/VTF-3. Maybe your wife will go for the 25-31 since it's considerable shorter than the 20-39.

I read that HSU is better for music and the SVS for Theater. I'm in the 70/30 camp favoring movies but very much appreciate what I hear with SACD's.

Value overcame me so I got the STF-2 for $315 + tax at CompUSA and I am very happy. Wife got a $300 stand mixer with the savings....sometimes marriage is a compromise. LOL.
Originally posted by mimason
Wife got a $300 stand mixer with the savings....sometimes marriage is a compromise. LOL.
Exactly why I plan to stay single for the forseeable future. ;)
I just watched "Blood Work" on HBO HDTV. It's the first movie I've watched with my brand new STF-2. Had to take a shower in the middle of the movie. When I got upstairs to my bedroom I put the movie on my bedroom set so I could still follow the plot while I got ready for the shower. I could feel the gun shots.........UPSTAIRS!

What really impressed me was the LFE was so smooth and natural compared to my old boomy sub. The old sub was intrusive; the STF-2 blended with my other speakers for a realistic, pleasing experience. Sorry I'm not using the proper technical terms.

My room is roughly 11x18. It is my humble opinion that the STF-2 is all I need.

In truth, though I've never heard a (an?) SVS sub, I'd wager you can't go wrong with either SVS or HSU. You just have to figure budget, WAF, room size, and aesthetics of the sub itself.

Make your choice, order it, and unless it bugs you in some way. Be happy with your choice.

Good luck. Let us know what you chose, and how you like it.
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Yes, more and more movies are coming out with great subsonic bass
I would expect this in movies like T3, but when you start getting great LFE in "Finding Nemo", you begin to become a believer!

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