should i be concerned

[Mike Brannan]

I have had my VFT-2 for about a week. It is the first purchase in a major upgrade of my audio system. As I have not yet purchased my amp and processor I have the VFT-2 hooked up to my old receiver. It is a 45 watt, 2 channel Onkyo receiver from the 70"s. Despite playing around with location and nobs on back of unit I cannot get a very decent sound. It's very boomy and muddy except on vocal type cd's and some lighter classical.

Tell me that my reciever is just not up for the job and that when I get my new gear everything will be great. I plan on getting Rotel seperates, near top of line. BTW the reciever is also powering and old set of JBL- L-50's.

Or maybe I don't have it hooked up right?

thanks

mb

[JohnnyMalone]

Did you look at the SERVICE tab? Hsu will provide FREE advice on positions!

[Sasha_G]

Assuming you are using a Dolby Digital receiver, complaints about "boomy" bass usually are traced to two major causes:

1) Placement
2) Volume Level turned up too high


Important placement guidelines:

• Always maintain 3 inches clearance between the ports and nearby surfaces.
• If you have hardwood flooring, use a throw rug under the subwoofer to absorb unwanted vibrations.

“Rules of thumb” for placement:

• Avoid the center of the room: In general, avoid placing the subwoofer half way between the front and back walls. You should also avoid sitting in that area. No matter how powerful the subwoofer is, there will not be much bass around the center of the room. This is where you get a strong null from your room’s standing waves.
• Use corner placement: Subwoofers usually sound best tucked in a corner. Good corners are far from wall divisions and have more than 6 feet of wall to either side. If you have more than one good corner, use the one farthest away from large room openings or the one closest to the listener. Try to keep the subwoofer within 1 foot of the wall.
• Use nearfield placement: A good subwoofer usually sounds best close to the listening position. In addition to nicer sound, the subwoofer’s volume level will be lower so neighbors are less disturbed. We strongly recommend this method if your couch is up against the back wall and your room is over 18 feet deep.
• Use “subwoofer crawling”: This very good technique uses the room’s acoustical reflections to your advantage. Place the subwoofer in the listening position, towards ear level if possible. Connect the subwoofer to the system and play some music with steady and constant bass. Walking around the room, listen for the nicest and most even bass. When it starts to sound good, verify by crouching down or getting on your hands and knees. You may also use a SPL meter to measure the evenness of the bass. The location that sounds best is where the subwoofer should be placed.


Volume:

Many people use ordinary music recordings or soundtracks for setting the subwoofer’s volume level. Try adjusting the subwoofer’s volume level so it matches the main speakers at the listening position. Some listeners prefer to set the bass level somewhat higher than the main speakers partly for loudness compensation, since most people do not listen to material at reference levels. A good approach is to set the subwoofer level to the highest level where it still sounds nice and where bass and kick drums sound tight and non-boomy.

For home theater applications, most people prefer to set the subwoofer level higher than the other speakers. We suggest setting it about 3 dB higher. Some processors/receivers allow you to set different bass levels for different sources.

For the most precise integration with your main speakers, go through test tones with a SPL meter. Setting the level using test tones by ear may result in misconfiguration, so please use a meter.

An analogue Radio Shack SPL unit is inexpensive and works better for this application than the digital Radio Shack SPL meter. Use the "C" weighting and “SLOW” settings

We recommend using a test disk with one-third octave filtered pink noise or warble tones. Measure from the listening position with the volume at a normal listening level. Do not play the test tones extremely loud as this might damage your speakers. Take measurements of four different tones above the crossover point and four different tones below the crossover point. Note that the Radio Shack meter is down about 12 dB at 16 Hz, 7 dB at 20 Hz, and 5 dB at 25 Hz. Add these numbers to the readout to compensate for these errors. The meter is more accurate in the higher regions. Average together each set of four measurements and adjust the subwoofer’s volume level to compensate. Repeat the measurements until the subwoofer matches the other speakers.

A less accurate method uses the receiver’s test tones, which are usually not in one-third octave increments. Measure from the listening position and set the subwoofer volume level to match the other speakers.

[Lwang]

• Avoid the center of the room: In general, avoid placing the subwoofer half way between the front and back walls. You should also avoid sitting in that area. No matter how powerful the subwoofer is, there will not be much bass around the center of the room. This is where you get a strong null from your room’s standing waves.
• Use corner placement: Subwoofers usually sound best tucked in a corner. Good corners are far from wall divisions and have more than 6 feet of wall to either side. If you have more than one good corner, use the one farthest away from large room openings or the one closest to the listener. Try to keep the subwoofer within 1 foot of the wall.

I don't agree with these recommendations. Placing the sub in the center of the room will result in the inability for the sub to excite odd order room modes. This would result in less boomy one note sub sound in those frequencies. Other places to put the sub would be 1/4 or 1/3 way along the wall, to minimize other more problematic resonance that you might encounter.

As to corner placement, you are exciting all the room modes for the sake of SPL. If you got a weak wimpy sub and you insist on hearing all the kabooming LFE at reference level from the DVDs, then that might be the place to put the sub, but generally, it is the least desirable for accurate reproduction. The rule of thumb is, corner placement will be better than some other randomly selected position, but it will not be the optimal location.

[Mike Brannan]

I appreciate the responses but not sure that you read my question. What I'm asking, is my sub performance problem linked to my average reciever and can I expect sugnificant improvement when I make my upgrade. That aside I have been expereminting with placement, etc, and have coaxed some better sounds out of the box but still getting boom and mud on rock and roll tracks.

[Sasha_G]

There is always the chance the receiver is causing the issue. We would have to experiment with the receiver by taking a subwoofer that is known to work well and plugging it into the receiver.

The VTF-2 shouldn't distort like that.

Dr. Hsu should be in the office later today and tomorrow. He would be able to troubleshoot the issue better than I. Please call us at 1-800-554-0150 and leave your number if Dr. Hsu is not in.

[haionlife]

Mike,

How do you have the VTF2 hooked up to your receiver and how are the speakers hooked up? I'm assuming you have the speaker outputs from the Onkyo run into the sub the from the sub to the mains...if the Onkyo has dual speaker outputs, try hooking the sub to one and the mains to the other. That may help, and it also allows you to easily switch off your mains and only run the sub. Run some good clean bass tracks through it and listen to the sub. If its still boomy and bloated then I would say the receiver (or maybe your input device) is the issue.

The mains might be part of the issue thats clouding the bass...running them full range on demanding rock tracks can sometimes push their low ends a little outta whack (especially with an older low powered receiver), but you only notice it when you add the bottom octive and it sounds "smeared".

For some good bass tracks see the posts in the thread Musical Bass Tracks under Subwoofers and Loudspeakers.

Good luck!

Mark

[Mike Brannan]

Thanks haionlife and Sasha, Yes I do have the speaker outlets from the reciever to sub-to mains. I will try the alternative hook-up. I have been getting some better response with placement experamintation and will also work on that. I have a very challenging room, a loft with 13 ft celings and open areas, basically one big open area, so I'm sure that is a factor as well. I will diagram the room and send it in to HSU when I get a chance.

I am also still thinking, (hoping) that my very average reciever and cd player are part of the problem and that the upgrade will take the sub to a higher level.

thanks guys,

MB