HO questions

[dafeist]

Hey, I just bought a nearly brand new VTF 3 HO with turbo and sold my VTF 3.2. After hooking it up, I do hear that it can dig deeper louder and the 3.2. However, I dont hear much else. I calibrated it using AVIA. What am I missing or is there something Im not doing correctly? The turbo is plugged in airtight as I didnt hear any noise coming from it during tests. I also didnt feel much air being pushed out of it during the 16 hz recording from HSU. Dont get me wrong, it puts out significant bass so I know its not "broken", but I really dont hear much of a difference between it and the 3.2 other than a bit louder down low. Any help would be appreciated. Thanks and take care.

[Pete_Hsu]

dafeist, presumably you have set the bass extension switch on the amplifier to max extension mode, right? Also, have you tried using max output mode (with no turbo)? If you don't mind, I'd love to see a sketch of your room too.

Note that the VTF-3 Mk2 should at least hold it's own in the mid/upper bass compared to the HO.

Thanks

[dafeist]

Yes, its at max ex with the turbo in place. I could remove the turbo and put it to max out, but if I did, what would be the difference between that and the 3.2? Here is a link to the layout of my house. If north is directly LEFT, the sub is in the northeast corner of the great room. When I purchased the 3.2, I was advised to put it in the northwest corner and I will also try that today. But the HO is currently exactly where the 3.2 is. Also, interestingly, using AVIA to callibrate, I found that my HO sounds better with phase at 180 whereas the 3.2 worked better at 0. Is that common?

http://www.hilinehomes.com/PDF/2112.pdf

[Pete_Hsu]

Even in max output mode, the VTF-3 HO should be significantly stronger than the VTF-3 Mk2 at 25Hz and below, while having strong in-room extension down to 18-20Hz.

I'm not sure why phase 180 sounds better on the HO, but nothing to worry about. Perhaps the wires were hooked up opposite on the -3 Mk2, but it won't pose any issue since the phase can be inverted.

Note that the VTF-3 HO has a flatter frequency response than the VTF-3 Mk2, and the deep bass output capability is more in line with the mid-bass output capability, so it may actually sound a bit less punchy in comparison. Adding an MBM-12 would give you the best of both worlds.

Sincerely,

[dafeist]

I need to find a used C-C3 to complete my Connoisseur set up, then the mbm-12 comes home :). So would you suggest using the HO w/o the turbo in max output? Home theater sound is my concern, music sounds fine either way in my experience.

[Pete_Hsu]

For most program material, it is worthwhile using max output mode. Only with ultra deep bass content (pipe organ music, and certain movie scenes) would it be best to run in max extension mode. However, with MBM-12, you may as well run the sub with turbo to get the best of both worlds with respect to maximum output and deep bass extension.

[dafeist]

Is there any benefit to running the sub in max output with the turbo still attached?

[Pete_Hsu]

That would give you an overdamped, or rolled off, response. Some people prefer it that way. It certainly poses no danger to the subwoofer to run it that way. However, it is not a good idea to run the subwoofer with both ports open (no turbo) and amp set to max extension mode, as this could damage the sub.

[dafeist]

OK, I used the HSU provided test tones and my rat shack spl. Ran them all with max ext w/ turbo, max ext w/o turbo, and max out w/o turbo. I found only a single db difference at 16 hz with turbo vs. w/o in max ext. They both made a 6 db jump but w/turbo it came between 31.5 and 40. W/o turbo, it came between 25 and 31.5. They were pretty much the same the rest of the way up. I know Dr. Hsu's turbo will do what it is supposed to, but it obviously didnt in this case. Could this be because of ambient noise in the room (i.e. rattling), because there was a decent amount of rattling going on. or would the rattling cancel itself out since the room was basically a constant during the test. My crossover is controlled at the receiver and is set at 100 (no choice below that) If it helps, here are the raw numbers:

W/turbo w/o turbo Max out

16 hz 80 79 75
20 hz 82 82 84
25 hz 83 83 86
31.5 83 88 91
40 hz 89 89 91
50 hz 89 93 94
63 hz 92 90 90
80 hz 89 90 88
100 hz 90 91 90
125 hz 90 90 89
160 hz 90 88 89
200 hz 88 87 89
250 hz 86 87 86

Any suggestions, comments, etc are welcomed. Thanks

[Pete_Hsu]

dafeist, the frequency response should be similar between Turbo mode and port plugged mode. The differences would start to become apparent when looking at maximum subjectively clean output before the onset of port noise.

[dafeist]

Got it, I think. so the turbo allows you to simply play low frequencies louder before onset of port noise. So basically I should put the thing away until I buy an mbm-12, and until then use it on max output.

[Pete_Hsu]

Yes, that is probably what I would do, sounds like a great plan!

[dafeist]

OK, went through a bunch of demo discs and have come to the overwhelming conclusion that with the HO and the VAST majority of movies I watch, max output is the way to go. Now, that means I have to put an mbm in the mix. Was wondering about placement. I know nearfield is recommended and damn near necessary. But what if the nearfield placement is on the side of a couch which is also about 2/3rds of the way in the room , depthwise. Also, someday will be building another house and will be putting a dedicated home theater in there. I will have two rows of seats. How should I place the mbm in a situation like this?

[Pete_Hsu]

It's fine to have the sub placed on the side of the couch. Just make sure to give at least two inches of space for the woofer.

In your new theater room, if possible I would try to put the MBM-12 sideways directly behind the first row of seats and centered.

Sincerely,

[dafeist]

Pete's cool.

Three questions: If you were forced to choose preferences...

1. Cheap or expensive connects?
2. Top 40 or Classic Rock?
3. 2 HO's w/turbo or single 3.3 w/mbm (I know room dimensions are a concern but theres a gun to your head, are you really in a position to quibble?)

P.S. The referenced gun is neither real nor loaded. In addition, no animals were harmed in the writing of this post.

[Pete_Hsu]

cheap connects, top 40, and two HO's w/ turbo (because I would add an MBM-12 down the road anyway). :)