Shiva-x :(

Revolt said:

This was posted for me in the avs forums:

Your internal volume is 6.35 cuft, so when you subtract for the displaced volume of the ports,driver and amp, your final volume is about 6cuft. For two 4" ports at 17 inches long, your tune is almost 24hz.....and that's the problem. Plug up one port and you're tune will be 17hz. See if that takes care of the problem. Make sure you plug it completely. Stuff in a rolled up pair of socks and then tape a piece of cardboard over the front. You'll have a lot of port noise from the air speed, but at least the bottoming should stop.

Is this true? Do i have to build another box to the right frequency?

Click to expand...

The final volume is about 6 cubic feet. But the documentation calls for 100% fill and the two 17" ports are Precision Sound flared ports, their effective length is 16" each. It should be tuned about 21Hz with the two ports & 100% fill but you will find if you build that enclosure according to the Google Sketchup dimensions, the tune will be ever so slightly lower due to the location of the exit of the ports and it's proximity to the rear of the cabinet, effectively lengthening the port. It comes out more like 20Hz. Either way.... 1 or 2 Hz doesn't make much of a difference in this case.

The 100% fill also gives you a larger effective volume and a lower Qa. The final result of that & the subsonic filter is shown in the documentation.

If you go out on the Internet and ask for help, some of it will be good advice, and some of it will be bad. Start by troubleshooting it via the obvious things first. Get that resistor right, make sure you built everything to spec, make sure you have the coils hooked up right and make sure you are using the 100% polyfill. The couple Hz tuning difference at around 20hz isn't going to do all that much for the subjective sound quality of the upper bass.

I think you have other problems but you may as well start with everything as it should be before getting started trying to troubleshoot something.

Kevin Haskins
Exodus Audio

Did you ever mention the main speakers you're using? If they're the little guys that came with the HTIB setup maybe your new sub is just way overpowering them. A lot of times the very small sat speakers that come in the sets will not have very good low frequency extension, and that might be why you aren't hearing any presence in the upper bass.

You shouldn't need a new receiver, since any modern receiver should do a good job in a starter system. Did you ever find out how to set the crossover point? There's no online manual at the Sony site, so I'm just guessing here, but there has to be SOME kind of settings for either "speaker size", "LFE crossover frequency", "LFE mode"... anything like that. If possible, you want to set the LPF on the receiver higher, or the speakers to "small". Make sure the crossover on the plate amp is wide open (set as high as it can go) or disabled.

Can you test by putting a different pair of larger speakers as the mains? Either from another setup, or borrowed from a friend or something?

Revolt said:

Thanks kevin. How much is 100% fill for this box?

And i really don't mean to be so stupid, or offend anyone. But if the resistor isn't it, and the box isn't it then what is it?

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Let's back up a step.

1) Could you try to describe what you don't like about the sound? "not good at all" doesn't give us much to work with. What are you listening to at the time? What instrument(s) or sound(s) are you equating with upper bass? Are you equipped to use REW...just need a PC, a sound card, and a RadioShack SPL meter?

2) How do you have the BASH-500 configured? Since your receiver has bass management engaged, the xover should be disengaged/LFE enabled to bypass the BASH's onboard xover.

3) What main speakers are you using? If they're still from the HTiB, you might have a big hole between the "mains" and the Shiva. Found the user manual for your HTiB package. The main speakers only have 2.75" full range drivers in sealed enclosures. The receiver's xover point isn't specified, but appears to be permanently engaged. IOW, Sony designed the receiver/speakers/sub to work as a package (hopefully there was some actual effort in the integration). OTOH, the BASH amps, like most subwoofer plate amps, appear to have a fixed lowpass around 200Hz, even when using the LFE input. This can be seen in both the Oaudio 300 and 500 frequency response measurements and it's probably safe to assume it's present in P-E's versions.

-Brent

The sound drops off db wise when the tone isn't super low. Example, if you know the song i put on by young jeezy, there is 4 bass tones. The shiva really hits on the 4th, but the first 3 aren't very hard hitting. Some of the bass notes, like the ones in Paper planes by MIA make the sub sound like a snare drum, not like it should sound. By upper base i actually just meant everything except the real lows. I use mac's... unfortunately. I don't have an spl meter.

2) Not sure if the reciever does have bass management, it has setting to change the db's of the sub. I have the phase switch off.. auto on on.. the other switch set to crossover.. the freq knob is set all the way up. And the volume set to whatever will make it not bottom out.

3) My main speakers are, for front and left.. Polk S10 Towers, and for the Center a Polk Csi3. The surround are in walls from monoprice.com. I plan on getting a new reciever in the next couple months for i can get the sub to work with it for now.

The people over at avs think it is the freq of the box.. here is my thread over there:

http://www.avsforum.com/avs-vb/showthread.php?t=1129932&page=4

Revolt said:

The sound drops off db wise when the tone isn't super low. Example, if you know the song i put on by young jeezy, there is 4 bass tones. The shiva really hits on the 4th, but the first 3 aren't very hard hitting. Some of the bass notes, like the ones in Paper planes by MIA make the sub sound like a snare drum, not like it should sound. By upper base i actually just meant everything except the real lows. I use mac's... unfortunately. I don't have an spl meter.

2) Not sure if the reciever does have bass management, it has setting to change the db's of the sub. I have the phase switch off.. auto on on.. the other switch set to crossover.. the freq knob is set all the way up. And the volume set to whatever will make it not bottom out.

3) My main speakers are, for front and left.. Polk S10 Towers, and for the Center a Polk Csi3. The surround are in walls from monoprice.com. I plan on getting a new reciever in the next couple months for i can get the sub to work with it for now.

The people over at avs think it is the freq of the box.. here is my thread over there:

http://www.avsforum.com/avs-vb/showthread.php?t=1129932&page=4

Click to expand...

I personally think the problem is the receiver's fixed crossover is too high, causing a gap between the mains and sub. With the Bash xover engaged, you're rolling the Shiva's output off above 150Hz. At best, you're getting a double filter that may be causing phase issues in the xover region. Switch the BASH to "LFE" to get its xover out of the loop. To add insult to potential injury, that receiver doesn't do any delay processing on the sub out; a factor that becomes more important the higher you go in frequency due to localization of the source.

I think REW should work with a Mac...it's written in Java. An SPL meter comes in handy for all sorts of things audio related. It's crude by comparison, but you can try to identify the problem frequencies by ear. Download and burn this CD and experiment.

As Kevin already mentioned, the difference between a 24hz and 20hz tune isn't that significant, especially since you're getting into the range that's felt more than heard. In 6ft^3, you're talking about a difference of 2dB in the peak centered at 28Hz. You can make bigger changes just by moving your furniture or the sub. Get some sort of stuffing in the box, if you haven't already. I personally like good ol' R-19 fiberglass batting, but some worry about potential health issues. Start by lining a couple of walls and see what happens. I changed the effective tuning of a 1 ft^3 gross box by nearly .5 ft^3 with just two walls covered in R-19.

-Brent

OK, it sounds like we might have it figured out here. If that receiver was designed specifically to work with the little speakers and sub it came with, and won’t allow any sort of adjustments, I think Brent is right. Your mains (the Polks) aren’t getting a full range signal, or even close to it. They’re probably being cut off somewhere around 200Hz, which is why you’re not getting any mid or upper bass from them.

The sub amp may be crossing over at a lower frequency (I think it ranges from 50 - 150Hz or so if you have the LPF engaged), which leaves you with a big hole where no sound is allowed in either the sub or the mains. The sound you are missing would usually be filled in by your mains, but the receiver won’t let them play it in this case.

If you can defeat the crossover on the BASH, you may be able to get that sound back, and it will play through the sub. Not ideal, but it should at least give you a little bit “fuller” sound.

I think the only real problem is that the receiver has the fixed crossover that is too high to use with bigger speakers. Your Shiva should play fine, if it were getting the right signal fed to it (at least that’s my take on it so far).