VTF-2 too slow for my Quads?

[spoonfed]

My VTF-2 got delivered today. A refurbed unit that saved my quite a bit (given in Australia) and apparently has been fitted with a new driver, which is a bonus (it looks brand new anyways).

While I purchased the unit for movies, not for music, i have spent much of the afternoon trying it out with music.

However, as with many other subs i have tried (but not to the extent) the bass from the sub seems to slow, and even linging compared to that of my mains. Mains are Quad 12L's.

I've filled out the form on the site for placement ideas (mainly for movies again) but perhaps this may help.

At present i have the sub behind seating, in a 4.2 x 3metre room (sitting long ways) with seat 0.8 of a metre off the back wall and mains around 1metre off the front wall.

The VTF-2 is certainly closer to the quads to the few others i have tried (M&K etc etc).

It does go deep, and im happy with it.

The only other issue i need to rectify is a sort of "after boom" on movies. Ie in Saving Private Ryan or U571 when many of the exposions occur, an after rumble/boom occurs, this seems over emphasised to the point of being a bit distracting. It proabably is my room. Moving the sub to the rear improved "feel" and reduced this "boom" from when it was at the front.

The room as stated above has 1 standard size archway on the right wall (centre of) into an ajoing room with exposed beam ceiling, otherwise it is completely closed

Any ideas would be great.

(i wonder if the neighbours will start complaining now :) ).

Danny

[Sorny]

Do you have the whole setup calibrated with a setup disc and an SPL meter? My TN1220HO subs sounded "slow" when I had them grossly miscalibrated... Once properly calibrated, the "slowness" went away. Might be worth checking out. Also, you might try lowering the crossover on the sub if possible.

Sorny

[spoonfed]

I've had a bit more playing. Have got it a bit better. I think behind placement seems to be the go.

Most music, and seemingly all/most good music (ie rec quality, not type) seems to be pretty good now, just some songs hmmm hard to explain :)

I haven't done SPL yet. Im wondering what is the best way to acheive good "blend" and what spl testing i should do. Don't really have a test disc, any recommended songs?

The above relates to music only.

[Sorny]

Well,

I do my calibration by hitting "calibrate" on my receiver (Pioneer Elite VSX-45TX, VSX-2011 for other than North American markets), which is little more than me plugging a mic into the receiver and the receiver making all sorts of noise and coming back with gain/distance/EQ settings (which are dead on).

I double check MCACC (auto calibration) with Avia and an SPL meter. I've found that the proper settings for movies are also the correct settings for music (I bump the gain on the stereo input for the sub up by 2dB for extra 'oomph', but keep the speakers set as small and have the subwoofer engaged with an 80Hz crossover).

I'd start with Avia or Digital Video Essentials and tweak from there...

The HSU test disc I got when I bought my TN subs has warble tones, pink noise, and all sorts of tests on it that would work great with an SPL meter to balance the output of the sub with the speakers. Did your sub not include the test/demo disc?

There are other CDs with test tones, but I'm not aware of their titles or catalog numbers. I'm pretty sure there is a Stereophile test CD available for sale that should help you get the sub dialed in even better.

Good luck,

Sorny

[spoonfed]

I guess as mine was "refurb" perhaps did not have a disc. Through in some other DDD recording but not exactly a test disc.

I'll have to borrow my mates SPL metre and have a hunt for a decent test disc, perhaps what you suggested will do.

Thanks for the input

I often see your input on AVS when HSU pops up :)

Danny

[Lwang]

To integrate boxy subs with dipole speakers, the best thing to do is to cross it over as low as absolutely possible. This could be in the 40-50 hz range if you are bi-amplifying, or run the sub in bass-augmentation mode, letthing the sub pick up where the bass in your Quads roll off. If you are using the crossover on the sub, don't assume what's specified on the dial as being accurate because it is not.

Usually, by the time you think the bass is too boomy, you are at least 5-10dB high in SPL.

As far as setting the level accurately, for HT, those general pink noise level matching for main & sub is the preferred way. But for music, I think it is much more important for you to to match the level at the crossover freq. This means the -3dB point (or -6dB, depending on the type of xo) of the low pass matches the high pass, and when measured together, there should be a seamless transistion from mains to sub. You could do this with test discs with 1/3 octave warble tones.

The pink noise matching of SPL between mains and sub are too vague for seamless speaker/sub transition. A few peaks in your sub's response will cause you to set a too low a level for the sub, a low crossover freq will do the opposite.

[Ddavidson]

The only other issue i need to rectify is a sort of "after boom" on movies.
It will be a room mode not the subs performance, as after 6 years I know the VTF-2 pretty well. Changing position may help a little.......but I bet once you start measuring with some 1/3 warble tones you will find the VTF-2's low bass is just exciting your room at certain low frequencies.


Hsu Research / Boston Audio Society Bass Test Tracks

Third-octave-wide warble tones, 16-250Hz
These warble tones are at constant level, with frequency varied randomly over the space of one-third of an octave, centered on the standard ISO center frequencies. For example, the 20Hz warble tone varies between about 18 and 22.5Hz. The bandwidth is wide enough so the signals will not excite narrow room resonances too much, but narrow enough to give you a good idea of the overall bass response of your system.

The bands whose frequencies begin with 2, 5 and 1 are marked by a brief tone at the start. The sequence in hertz
(with tones marked by a t) is 16, t/20, 25, 31.5, 40, t/50, 63, 80, t/100, 125, 160, t/200, 250. [EBM]

http://hsuresearch.com/mp3/

Try burning the above MP3 test tracks and create your own test disc. Get yourself into RadioShack and buy yourself the analog Spl meter (2050) if they have any left. Do not forget to do the corrections or get the meter modified so it reads correct for low bass Spl.
Here is the web address For 2050 meter mods: http://www.gti.net/wallin/audio/rsm...50/33-2050.html
A refurbed unit that saved my quite a bit (given in Australia)Since you are in Australia here is another free test tone generator download that I have found is useful. It also happens to be from an Australian company.

NCH Tone Generator
Web: http://www.nch.com.au/tonegen/index.html

The VTF-2 is certainly closer to the quads to the few others i have tried (M&K etc etc).

It does go deep, and im happy with it.
I am not surprised your happy with the VTF-2. It certainly shocked a few audio friends when I first played some low organ. Most of whom thought it was at least a 12" and 250w like my older Tn. Not that it could play as loud and deep as the 1220, but it was a shock for them to see it was only a 10"/150w. Dr Hsu did a good job on this sub and it has changed the whole direction of the company. Hence the siblings sprouting from every corner of Hsu.

Once positioned as good as the room allows the little VTF-2 keeps pace with much more expensive subs. Quads intergration is very difficult for most subs, but given good acoustics the VTF-2 will prove better than anything in it's price range and will handly beat many above it .

As Wang has said with dipoles you always have to set your crossover low for bi-amp, or if you prefer as many do run bass-aug mode at the quads roll-off point.

Finding that sweet spot just takes experimentation and you might find that the roomis fighting against that goal. Once you get it set-up right the added depth and weight to the bass will bring a smile everytime you play the system. Enjoy your sub, it's from a great designer. It does everything very well unlike most boom boxes that cost even more $$.


Ddavidson

[david_da_kine]

Give it some time to break in - it will sound a lot different after a week or two.

[spoonfed]

Thanks for all the input thus far.

My HT room now resembles a disaster zone :) hehe

I've found centre front (behind thingy that holds reciever, centre etc) is quite good if the seating is moved around 1m forward, BUT this is not acheiveable.

Seating distance to front wall cant really be changed as it is correct distance for Projector Screen size.

What it has found though, the closer one sits to either the front or rear of the room the more the "boomyness" increases, this reduced somewhat having the sub at the same end (ie rear) as seating (but only a little).

Positioning sub in centre of room, but along left wall (opening oposite on adjacent wall) reduced boom much more, but at BIG expense of output.

I think for now i'll leave behind seating. This way a little less volume is need to give the same "feel" which helps reduce the boom.

As stated i think it is the room.

Only other question i now have is re the "auto on" function. Does the LED change colour when its in standby? I left the unit last night with switch in up position "auto on" and the amp was still warm this morning and light yellow. receiver and all other equipment was off still.

Danny

PS: Thanks for the links to the MP3's. A quick test (by ear till borrow mates SPL) finds a large and very noticable hump at round 40hz, this i think is causing the "boom". bellow and above this freq is is quite good and seemingly consistent. I guess adding an inline EQ could perhaps rectify this (if positioning cant)?

[Ddavidson]

the amp was still warm this morningThe VTF-2 runs warm all the time even when in standby mode. Stand-by is not really off so voltage still gets to the transformer which keeps the heatsink warm to a degree. The auto detection curcuit on any subwoofer tends to be next to useless and definitely not the best method for turning on and off the sub. If you get a lot of low to no bass scenes the curcuit consistantly go's into sleep mode far too easy.

On both my VTF-2 and my VTF-3 I have by-passed it and always turn it on manual when the system is in use. That way the clicking in and out in the long talking movies or low bass music is avoided. Also by turning off at the main toggle switch you are removing it from high voltage spikes and lightning strikes.

It is also important to remember that it is an AB class amp so it also runs warmer than a hybrid or digital D class. That is normal.

Ddavidson

[spoonfed]

My other sub it replaced (a Welling 12inch, u probably never heard of) had a similar "auto on" issue.

I rectified this by turning the gain down on the sub but bumping up the sub output on the reciver. Hence the reciever was putting more to the sub realitive to the overall volume level and hence kept it on easy. It definatly "clicked" off though, ie heat sink cold, could hear it click on etc etc.

I'll know more once i play but it seems the HSU is not turning off at all, i can't pickup any delay in turnon say i start straight up with a deap note. more testing i guess

Do you know how long the turn off time is. Ie time from last feed to the sub to time it goes to standby?

How much improvement should i see once the driver is run in? Will it give more "depth" or just more output? I compared back to back with my old one, it has more in both respects but was expecting a bit more (which may come).

D

[Ddavidson]

As far as the time set internally by Hsu it varies too much to be accurate but most people reported 1/2 to 2hrs. Hsu like other sub manufacturers had a lot of problems in keeping everyone happy with the sensitivity and there are even some photos here somewhere where you can via jumpers internally bypass the whole curcuit. It works good in theory but its crazy in practice.

The driver settles in after a few weeks of use and sounds even better as it settles.


Ddavidson

[Lwang]

Positioning sub in centre of room, but along left wall (opening oposite on adjacent wall) reduced boom much more, but at BIG expense of output.
That is how I have my sub set up, with the woofer roughly at the center point of the room. Lessened much of the 1st order room mode, but I presume I would have to crank up sub up much higher in order to get the same SPL.

[quoteWhat it has found though, the closer one sits to either the front or rear of the room the more the "boomyness" increases, this reduced somewhat having the sub at the same end (ie rear) as seating (but only a little).[/quote]
The more you bring the sub to a near field listening position, the higher the direct sound in relation to room induced resonance.