Does an audio system need a subwoofer?

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Re: Does an audio system need a subwoofer?

Postby Jon Agner » Tue Aug 17, 2010 5:45 pm

Gino wrote:It's mechanics is just like an rc helicopter collective. It is a mechanical system that can change the angle of the blades. Just Google up how swash plates work with helis. The motor shaft spins in one direction. By collectively varying the angles of the blades, you can change the pitch. The pitch can either blow air in front,to the back, or no air at all (zero pitch). With the rapid ability to blow air in front and back, you now have the dynamics of a woofer. In rc helis we can fly upright and inverted thanks to this. I can tell you first hand that this device can produce serious blasts of air with rapid transition from positive to negative pitch.

The picture suggests the main body is the motor.In front of that is a magnetic actuator to vary pitch. I am assuming it's magnetic because of the torque involved. In front of that is rotor head with mechanicals to individually and collectively change blade pitch from negative to positive.


Hmmmm... so it's in the speed of the rotation that determines the volume of air that will agitate, in order to reproduce the same intensity that of a regular cone woofer driver, given a specific frequency :) Now I understand :)
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Re: Does an audio system need a subwoofer?

Postby Gino » Tue Aug 17, 2010 5:57 pm

The speed of the main shaft I assume is fixed either mechanically or through the use of an electronic governor.It will be easier to meter air by fixing this speed and letting the collective do the rapid changes. This way, the system only needs signals for the amount and direction of pitch. The speed is just enough to meet the maximum air flow required at maximum negative or positive pitch.
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Re: Does an audio system need a subwoofer?

Postby trauma » Tue Aug 17, 2010 8:00 pm

Gino wrote:The speed of the main shaft I assume is fixed either mechanically or through the use of an electronic governor.It will be easier to meter air by fixing this speed and letting the collective do the rapid changes. This way, the system only needs signals for the amount and direction of pitch. The speed is just enough to meet the maximum air flow required at maximum negative or positive pitch.


:rock:
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Re: Does an audio system need a subwoofer?

Postby qguy » Wed Aug 18, 2010 8:47 am

I had the assumption that the rotation of the blades is constant and the blades moves back and forth at a fixed angle to produce different frequency just like a regular woofer
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Re: Does an audio system need a subwoofer?

Postby Gino » Wed Aug 18, 2010 9:20 am

From the site:

"A motor controller and electric motor rotate a set of blades at a constant speed. The TRW-17 Rotary Woofer pitch mechanism uses a conventional voice coil and magnet assembly. This is connected to your amplifier to pitch blades in proportion to the applied audio signal. As the blades pitch while rotating a pressure wave is generated, the degree of pitch controls the amplitude of the pressure wave. Air is allowed to transition through the blades. Thus oscillating the pitch of the blades creates sound while they are rotating ."

Pitch is blade angle. Oscillate pitch is to change the angle. The blades change angle. Clear as day.

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Re: Does an audio system need a subwoofer?

Postby soundpurist » Thu Aug 19, 2010 10:41 pm

A system that can go as low as 10 hrtz to deliver that ultra low frequency and creeping energy is an incredible one. If that takes a subwoofer, then it does. Perhaps same with super tweeter that scales beyond 35khrtz to 100khrtz. Who cares if it's beyond the humar ear's senses. In fact some hi-end speakers incorporate these two devices properly tuned to deliver the full spectrum of audio signals.

The problem in adding a sub with existing stereo system is proper integration, a worthy challenge for an enthusiast. In my experience it takes proper finetuning of crossover loads, driver matching, power amp, and of course PATIENCE :) to nail it.
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Re: Does an audio system need a subwoofer?

Postby muypogi » Sun Aug 29, 2010 3:18 am

If you have smallish standmounts like I do, then my answer is yes.

A few caveats though:

1) It does take proper tuning and fiddling with the sub to achieve almost seamless integration. Pag na break in na yung sub, then that's another round of fiddling as well. If you have the budget and space allow for 2 subs, then I think that's the way to go. If you're financially challenged just like me, make the most our of one sub. Pero may directionality pa rin, specially with subs 12 inches or higher. . .

2) For me, sealed subs sound best for stereo (or SQ or sound quality during my car audio days). Even the best ported ones exhibit the attribute na "gumagapang na bass" . . . something that I prefer in movies but not in music. I'd have to turn down the sub to remove the creep, pero you lose some of the bass reinforcement. To my ears, sealed subs let you get away with some more volume.

3) Though I have a stereo amp with room correction modes using the LFE output, the best connection based on my ears remains speaker level connections to the sub, Theoretically, your sub gets the full range signal as your main speakers, allowing them to move more in time with the mains. For me, they just sound better and integrate better vs using the LFE input of a sub. Parang something is lost pag ginamit mo yung LFE connection. But that's just me.
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Re: Does an audio system need a subwoofer?

Postby Nelson de Leon » Sun Aug 29, 2010 7:38 pm

muypogi wrote:If you have smallish standmounts like I do, then my answer is yes.

A few caveats though:

1) It does take proper tuning and fiddling with the sub to achieve almost seamless integration. Pag na break in na yung sub, then that's another round of fiddling as well. If you have the budget and space allow for 2 subs, then I think that's the way to go. If you're financially challenged just like me, make the most our of one sub. Pero may directionality pa rin, specially with subs 12 inches or higher. . .

2) For me, sealed subs sound best for stereo (or SQ or sound quality during my car audio days). Even the best ported ones exhibit the attribute na "gumagapang na bass" . . . something that I prefer in movies but not in music. I'd have to turn down the sub to remove the creep, pero you lose some of the bass reinforcement. To my ears, sealed subs let you get away with some more volume.

3) Though I have a stereo amp with room correction modes using the LFE output, the best connection based on my ears remains speaker level connections to the sub, Theoretically, your sub gets the full range signal as your main speakers, allowing them to move more in time with the mains. For me, they just sound better and integrate better vs using the LFE input of a sub. Parang something is lost pag ginamit mo yung LFE connection. But that's just me.



Correct sir. by using the LFE, there is a "sharing" of signals between the stereo amp & sub amp. I believe your current stereo amp is the HK?
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Re: Does an audio system need a subwoofer?

Postby muypogi » Mon Aug 30, 2010 9:13 am

Yup itis the HK. Tried using the LFE output and the room correction for LFE. Medyo parang walang galaw yung sub and mahina, even withthe sub level at + 6. . . Just waiting for sub driver to break in. Medyo mstgas pa ng konti.
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Re: Does an audio system need a subwoofer?

Postby cia » Mon Aug 30, 2010 9:24 am

Maybe this device will solve most of the subwoofer integration with the main speakers and room acoustics problems....DSpeaker Anti-Mode 8033 Automatic Subwoofer Equalizer. If anyone has this locally. pwede pa hiram for audition.

http://www.dspeaker.com/en/products/ant ... 8033.shtml
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Re: Does an audio system need a subwoofer?

Postby conspicuous » Sun Sep 05, 2010 9:23 am

cia wrote:Maybe this device will solve most of the subwoofer integration with the main speakers and room acoustics problems....DSpeaker Anti-Mode 8033 Automatic Subwoofer Equalizer. If anyone has this locally. pwede pa hiram for audition.

http://www.dspeaker.com/en/products/ant ... 8033.shtml


cia, thanks for sharing this article. this would really help a great deal i think although it's additional cost. I saw a sub, velodyne i think, that comes with a microphone. this way the sub can "listen" then adjust itself accordingly. just like some HTB operate. :)
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Re: Does an audio system need a subwoofer?

Postby Nelson de Leon » Thu Sep 09, 2010 8:28 pm

Stagea wrote:
Nelson de Leon wrote:
Nelson de Leon wrote:@ Stagea:
I think you have an empty space under your 2 beds. It might be another culprit.


Yup, that's also a problem hehehe. It sounds OK now. I can live with it. :)


Better living ka na ngayon with your dual subs. I'm impressed! Very well integrated na. Updates naman... ;)
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Re: Does an audio system need a subwoofer?

Postby Stagea » Thu Sep 09, 2010 11:28 pm

conspicuous wrote:cia, thanks for sharing this article. this would really help a great deal i think although it's additional cost. I saw a sub, velodyne i think, that comes with a microphone. this way the sub can "listen" then adjust itself accordingly. just like some HTB operate. :)


May ganyan nga, I forgot the brand na din.

Mordaunt-Short's Mezzo 9 is simpler, but is just as cool. The remote control is also an SPL meter. The sub comes with a test / tuning CD, that you can use to properly calibrate and integrate the sub. Just run the disc and use the remote to get SPL readings from your listening position. Then set the sub's notch and boost filters to compensate for the in-room response. :)

Nelson de Leon wrote:Better living ka na ngayon with your dual subs. I'm impressed! Very well integrated na. Updates naman... ;)


Pwede na, I retuned the sub enclosures by reducing the port cross-section. This flattened the response considerably, and helped the subs extend lower. I also ran an external crossover for better integration with my front towers. It's far from the best, but it's tolerable na.
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Re: Does an audio system need a subwoofer?

Postby Stealth » Fri Sep 10, 2010 8:15 am

Hi guys, can u actually hear or feel the difference between an active sub specs of 29 hz and 25 hz frequencies?
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Re: Does an audio system need a subwoofer?

Postby qguy » Fri Sep 10, 2010 8:33 am

if both are flat to 29 and 25 I would assume it would be difficult as both subs will still produce sound below that range even down to 20hz, rolled off nga lang ....

Stealth wrote:Hi guys, can u actually hear or feel the difference between an active sub specs of 29 hz and 25 hz frequencies?
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Re: Does an audio system need a subwoofer?

Postby Nelson de Leon » Mon Sep 20, 2010 9:43 pm

Hi guys. I tried to integrate my sybwoofer in my audio results. Suprisingly, here is the result:

Image
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Re: Does an audio system need a subwoofer?

Postby Stagea » Tue Sep 21, 2010 7:03 am

Stealth wrote:Hi guys, can u actually hear or feel the difference between an active sub specs of 29 hz and 25 hz frequencies?


Granted na F3 point yan (measured in-room), malaking factor pa din kasi yung rolloff nila below that frequency... kung steep ba or gradual.

A sub with an F3 point of 29 might actually sound deeper than the one rated with an F3 of 25, kung shallow yung rolloff nya below 29Hz. Another is kung pareho ba ng way of measurement. Anechoic chamber response ba, room response ba (ano room dimensions?), F3 ba or F6 (some even use F10 values), etc.?
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Re: Does an audio system need a subwoofer?

Postby Stagea » Tue Sep 21, 2010 7:04 am

Nelson de Leon wrote:Hi guys. I tried to integrate my sybwoofer in my audio results. Suprisingly, here is the result:

Image


Wow! Ibang level nato. :) Ganda naman ng blending master.
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Re: Does an audio system need a subwoofer?

Postby Nelson de Leon » Tue Sep 21, 2010 9:33 am

Member din kasi ako ng chamba motors. :D Kiddin aside, thanks for designing my enclosure properly. ;)
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Re: Does an audio system need a subwoofer?

Postby Gino » Tue Sep 21, 2010 9:38 am

Your subwoofer enclosure looks good by the way (sent through pm). Are you using an external amp and crossover or do you have a plate amp for it?
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