Does anyone own a sunfire true sub ? I have some questions.

I have owned a True Sub MKII and two Signatures. I'd be glad to take a shot at your questions.

Hey, thanks for the reply. I was just wondering how you have you're set up. I placed my mkII, in the corner as the manual recommends, and i've also tried it along the wall, farther out from the side wall, but either way, haven't been that impressed with the output. I know these subs can put out alot of bass, 2700w is a lot of power, so i'm just wondering what i'm missing here, maybe i don't have it turned up very loud, because i have it set with a sound level meter to match my other speakers output, but i guess i just expected to be blown away with bass, and it just hasn't happened yet. Thanks

take it back and buy a velodyne.

If your using a Radio Shack SPL meter it won't give you the right reading on your sub. If you set your other speakers at 75db on that meter try another 10 to 15db higher on the sub and you should get some better results

Hope this helps
Lasher

[This message has been edited by Lasher (edited March 24, 2004).]

2700W may be a big number - but it's probably the least relevant spec to consider when buying a powered sub. The Sunfire needs that much power to overcome the limitations inherent in the rest of its design. In this case you are getting "small and out of sight" for the cost of "needs huge amount of power."

Nothing wrong with that per se. I have listened to Sunfire subs in good demo rooms and have been pretty impressed with them - as I have been with a lot of what Bob Carver has come up with in his career.

And I'm also a big Velodyne fan.

Jeff Mackwood

When people are disappointed in a subwoofer, I sometimes wonder, “What were they expecting?” I don’t know what your expectations are, so I’ll “philosophize” for a moment first.

Some people add a subwoofer because they want more “thump” from drums, more “dwoong” from electric bass, more concussion from explosions, etc. Problem: while a lot of the amplitude for these sounds comes from the low-bass frequencies, most of the acoustic information that your brain needs to interpret these sounds as you would expect them to occur comes from frequencies well above subwoofer range. A true subwoofer (not a reference to the Sunfire naming scheme but to any sub which reproduces only the lowest frequencies) will likely add amplitude and extend downward the range of the low-bass frequencies in a system. This gives more “um” in “thump”, more “oon” in “dwoong” and more rumble, but not slap, in explosions. This is why a subwoofer that acts only in the low-bass frequencies must be properly blended with the speakers in the rest of your system. Having “full range” speakers that do a good job in the mid-bass and upward frequencies is vital.

A word about “2700 watts.” I think that the 2700 watt figure, according to Sunfire’s own information, would only occur if the internal amplifier were to go to maximum output feeding a non-reactive resistance equal to the active driver’s coil impedance while at rest. Consider that the coil will provide an increase in effective impedance due to back EMF (voltage) arising from the magnetic flux generated by the incoming current and the motion of the coil through a magnetic field. If the active driver is moving rapidly through large excursions, such that the effective impedance doubles, triples or quadruples, the maximum wattage the driver will accept from that very same amp falls to 1350, 900 or 625 watts respectively. You can read through Sunfire’s web site technical information pages if you would like to know more. I think this material is educational no matter what brand of subwoofer you like. Having 2700 watts available for sudden acceleration in that small cube is a bit like having a few hundred horsepower ‘under the hood’ of your car. Holding steady at 55mph, you might be using 15% of your maximum available horsepower. Like to drive 85? Now you might use 35%. Even if you ‘floor it,’ you will see your maximum horsepower in only a narrow band of the engine’s operation.

The first sub I owned was an MKII. I purchased it about six months before Sunfire introduced their Signature model. Of course there was no Outlaw LFM-1 at that time, and Velodyne did not yet offer a “small cube” style subwoofer that could compete with the Sunfire. I absolutely needed a small sub that could be kept out of the way and yet deliver lots of bass with low extension, and the MKII delivered just that.

I used my MKII almost in the corner. I think these high pressure, small diameter, large excursion drivers really need a corner, creating a loaded, low-end, closed horn out of the room itself. Especially true of small footprint subs, as many here can likely attest, subwoofer placement is both often crucial and often frustrating. Twelve inches in any direction resulted in changes I could easily detect. My experimental placement increment, the distance I would move the sub between listening evaluations, ended up being about three inches at a time. Besides experimenting with distances like 11” from the corner and 5” from the wall, you might also try 3” off the floor.

The level control on a Sunfire sub is very sensitive to small movements. I didn’t realize just how sensitive until I tried trimming just 1dB off the sub’s level while watching an SPL meter. I have found the blending of a true, lowest-frequencies-only, subwoofer to be challenging. 2dB too high and it sounds muddy, undefined, booming. 2 dB too low and you’re wondering where the bass went.

I don’t know what type of signal handling or processing you are using but I’m going to assume that it is properly set up. What follows is a description of the way I have handled initial subwoofer set up. After the initial setup, you can spend hours experimenting if you wish.

Sub’s crossover setting: I let the receiver/processor/other active crossover handle the dividing of frequencies, so I set the subwoofer’s crossover point to it’s highest. I think that it’s 100Hz or 120Hz for the MKII.

Receiver/processor/other active electronic crossover point: if the MKII is OK up to 100Hz, and the smallest of your other speakers still has fair output at 60Hz but not much lower, I’d pick 80Hz. Do your other speakers do well down to 35Hz or so? Perhaps you can try 60Hz or lower crossover points later. I’ll use 80Hz in this example.

With the subwoofer level at zero, balance your other speakers with an SPL meter.

Subwoofer phase and level: Subwoofer phase is most important at the crossover point because frequencies very near the crossover point will be reproduced in both your regular speakers and your subwoofer at the same time. Setup: place one of your main speakers, let’s say the left for this example, about two inches from the sub, the main speaker’s woofer facing and centered with the sub’s active driver (not the MKII’s passive driver). With your receiver/amplifier safely off, purposely wire the main speaker with the leads reversed. With power back on and volume down, feed an 80Hz test signal to a left channel input on the receiver/processor/other active electronic crossover that will end up sending what is intended to be an equal signal to both the main speaker’s woofer and the subwoofer. With the subwoofer level at zero, turn up the main volume until you hear a moderate 80Hz tone. Now slowly turn up the sub’s level until you can tell that the sub’s driver is moving and stop. Adjust the sub’s phase so that the least amount of tone is audible. Continue making small amounts of subwoofer level and phase adjustment attempting to completely cancel out the sound coming from the main speaker’s woofer. You might be surprised to find out you can see both the main speaker woofer and the subwoofer driver moving slightly and yet not hear the tone. This is because they are both moving the same amount of air, but 180º out of phase, canceling out each other’s acoustically radiated energy. Be careful not to touch the subwoofer level or phase adjustments accidentally if you move the subwoofer afterward. With the receiver/amplifier safely off, wire the main speaker leads normally before you put the main speaker back in its proper position.

If the tone used for this setup was exactly at the actual crossover point, you have accomplished two things. Near the crossover point the sub will be in phase with your main speaker; near the crossover frequency the sub is putting about the same amount of acoustic energy into the room as your main speaker would. You are near to having a good subwoofer-to-main speaker balance, although refinement may be needed. If your test tone was slightly different than the crossover point, you will need yet more tweaking.

Listening time: play some music that has certain bass instruments played prominently or even without other instruments. The best listening is to an instrument that has fundamental low frequencies in the subwoofer’s range and complimentary harmonics of the same notes in the range your main speakers will reproduce. Do you know how that instrument is supposed to sound? Is the low-bass portion strong but not muddy? If you feel that the sub needs a bit more or less, use an SPL meter close to the sub with a test signal that is stable to raise or lower the sub’s level by one or two dB only, then listen again. Keep track of the adjustments you have made so that you can go back to a previous setting if you need to. You’ll probably want to return the level to the initial setting each time you try the subwoofer in a new spot.

If the crossover is at 80Hz, I might compare levels of the sub at 40Hz and the main speaker at 160Hz. This is one octave below and above the crossover point. But because my meter is 3dB more sensitive at 160Hz than it is at 40Hz, the nearly balanced point will be when my main speaker reads 3dB higher at 160Hz than my sub will read at 40Hz.

I’m of the philosophy that if you’ve got the sub set properly for music, then the HT will also fall into place. If the sub sounds right with music, but rumbles either to much or too little during a movie, perhaps it’s the LFE level or something else that needs adjustment. It would be highly unlikely that you could adjust the sub’s level based on the sound of explosions in movies and have your music end up sounding excellent.

Well, I’ve gone on much longer than I had planned to, but I hope you find this helpful. Be patient, there are many variables. I find a well-adjusted system very rewarding.



[This message has been edited by bestbang4thebuck (edited March 26, 2004).]

Hey Thank you for the info. You gave me a lot to play around with, so i'll try your suggestions, and experiment some. thanks again.

Wow, every once in awhile you come accross a post that is truly informative and usefull. Bestbang's is one of those Very well done!

Regards,

Dave

Thanks for the compliment, Cowrock!

Discovery and/or light-hearted entertainment time: I you want to find out what a subwoofer is capable of with regard to timbre (how much of what you hear is going to be “thump” vs. “um?”) and output level (how much house-shaking can this do?): play some test and/or program material with only the subwoofer active. If you don’t have the capability to turn all your full range speakers off, you might have to do something like temporarily cable your CD player directly to the sub’s amplifier. Because you would be using the sub’s level control as a volume control in such a direct connection, hopefully you will entertain yourself with this test before you spend a lot of time fine-tuning the blending of your sub with the rest of your system. Oh, I wouldn’t have my sub powered up while changing cables!

[This message has been edited by bestbang4thebuck (edited March 28, 2004).]