Hey all. I just finished building a vented sub enclosure for my Adire Shiva.

I have a 950/7100 combo. I connected the Sub output from the 950 to one of the unused channel on the 7100. I connected that to the Shiva, whose voice coils are wired in parallel (+ to + and - to -).

The thing is, I don't think I'm getting the output I should from it. When calibrating my speakers using the internal test tone, all of my speakers calibrate to 75db at -9db, give or take. Even when I crank the sub up to +10db, I don't hear more than a hum. I feel a rumble, but not nearly the output I'd expect at reference level.

To verify this, I tried the same thing with Avia's test DVD, and achieved the same result.

I have my mains set to "Small" and the Subwoofer set to "On" in the 950's menus.

Any ideas?

Thanks!

-Joe

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Remember the Intellivision?
http://www.gotmaille.com/nostalgia/

Hmmmmmmm...

The Shiva has dual 8 ohm VCs, so parallel wiring makes it a 4 ohm load.

The 7100 is rated at 165 watts @ 4 ohms.

Sensitivity of the Shiva is 87 dB, 1W/1M.

I doubt you'll get ref level bass with this combination.
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The thing is, I don't think I'm getting the output I should from it. When calibrating my speakers using the internal test tone, all of my speakers calibrate to 75db at -9db, give or take.
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What is the main volume set at when you calibrate?

How big is the room?

What source are you playing?

Is the amp distorting when you 'crank it to +10'?

Also, you have no phase adjustment with this setup, and This may have something to do with the apparent anemia. Try reversing the speaker wires to see if there is any volume difference. Use your SPL meter and play a bassful tune, switch the speaker wires, play the same passage and note the SPL reading.

boss,

Thanks for the advice. Perhaps I just need a more beefy amp. I was hoping to use the Outlaw until funds arrive to buy a new amp. Where's our high power sub amp, Outlaw?!?

Let me address your questions...

--What is the main volume set at when you calibrate?

Zero. The other channels very easily put out 75db.

--How big is the room?

About 14x18. The sub is right in front of my seating position. I know, no loading, but it's a coffee table. My wife might get upset if I put the coffee table in a corner. "Bad coffee table! Go sit and think about what you've done."

--What source are you playing?

I tried the internal test tones of the 950, and the audio setup tones on Avia's disc. I just retested with Avia. It plays a tone on the main speaker, then the sub. I read 75db on the main speaker, but the sub didn't even register when I set the meter to 60db. I can hardly hear it.

--Is the amp distorting when you 'crank it to +10'?

I don't know. The only thing I push to +10 is the channel trim for the subwoofer channel. Even then, there's not enough audible information to tell if there's distortion. I can feel the sub's vibration through the floor (spiked), and there's air whoofing (I looked that word up) out of the port.

--Also, you have no phase adjustment with this setup, and This may have something to do with the apparent anemia. Try reversing the speaker wires to see if there is any volume difference. Use your SPL meter and play a bassful tune, switch the speaker wires, play the same passage and note the SPL reading.

I just tried this, and it made no discernible difference.

Thanks,

-Joe


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Remember the Intellivision?
http://www.gotmaille.com/nostalgia/

[This message has been edited by Nostalgia (edited September 18, 2003).]

Joe

It sounds like the Shiva may still be a bit hungry for power, but also keep in mind the Radio Shack SPL meter's low frequency inaccuracy . This is obviously not the problem that you are encountering (unless you're using a 10Hz test tone, which the 950 certainly doesn't do and I doubt Avia does either ), but it may be useful as you get further along.

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

More thoughts...what crossover setting have you selected for the main speakers? It sounds like you may have it set low.

You can try setting it higher, say 100 Hz and see if that changes anything.

Though I see now that you can't move the sub/table to a corner, try moving the SPL meter around the room and note any changes. You might at least be able to be sure the sub isn't centered in the room.

You can also try temporarily connecting each VC of the Shiva seperately to 2 channels of the 7100 (Y-jack from the 950's SW out), which will boost your amp power to 2oo watts total.

I agree that you should be hearing more output than you describe.

Make sure the cable from the 950 to the 7100 is good.

Joe,
Shiva is a very efficiant driver. Adire Audio mentions it’s ability to run efficiantly at 45 watts and handle up to 650 watts. I own one and I can’t ask for more considering it’s small price tag. Even if it costs more, I’ll still be happy with it.

Dedicated sub amps are not that expensive (unless you want real high power). If you haven’t, check out this site: www.acoustic-visions.com/

I would suggest going back and checking your internal wiring, Nostalgia. It sounds like you may have inadvertedly cross-wired the voice coils causing an out of phase condition. I believe your 7100 should supply sufficient power for this driver, giving you plenty of output- at least for now! By the way, I have 2 Shivas in sealed enclosures- I like 'em. Good luck!

Yes, I did have the xover at 40hz. Raising it to 80hz gives me about 65db from the sub when there's 75db coming from the mains. The subsonics are enough to rattle everything in the house, so I guess I'm on the right track. 80hz seems kinda high to be crossing the sub over, though.

Again, I'm probably more used to the car audio world. My HT sub seems to have more "feel" and less audible material than I'm used to.

Jeff's coming over this weekend, I'll have him give a listen.

Thanks for the suggestions,

-Joe

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Remember the Intellivision?
http://www.gotmaille.com/nostalgia/

I'm positive the internal wiring is right. I know this because I wired it wrong at first I've got the two voice coils wired + to + and - to -. I've got the terminal cup wired up red to the + and black to the -. I tried running the speaker wired from my amp both ways, in and out of phase, with no real change in sound.

Raising the crossover seems to have helped. I think I just need a second opinion

-Joe



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Remember the Intellivision?
http://www.gotmaille.com/nostalgia/

Your "training" in car stereo sound may indeed be the issue here since the "audible" bass you mention would, I think, tend to be in the upper bass range at 80Hz and even higher.

Some of the car stereos I've heard boost this range to create an artificial impact. It's impressive in its way but more bloated than accurate.

Play with an even higher crossover point, just for the heckuvit, and see what you think. It might help you suss out your preferences and tastes.

Then just live with it for awhile. You may just be getting accurate bass for the first time. Good bass isn't flooding all over the map but is solidly, decisively there when you need it.

Have fun!

[This message has been edited by boblinds (edited September 18, 2003).]

I found this link to SVS that shows how to compensate for the bass rolloff in Radio Shack meters. While it doesn't deal with your general problem, it might help your tuning.

http://www.svsubwoofers.com/faq_rscomp.htm

Hey, all. It looks like it was a combination of too low a crossover setting, and the speaker needing to break in. I also stuffed the box with 2lb of poly-fill, and re-sealed the driver. D'Arbingal was over this weekend, and we listened to some music and screened the Two Towers.

As if for confirmation, while watching the scene where the Nazgul is flying over the swamp on the dragon, a friend of mine walked in. It was his first time to my house. He had parked a block away because he didn't know where the house was. He said he just followed the bass.

-Joe



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Remember the Intellivision?
http://www.gotmaille.com/nostalgia/

Appreciate the feedback.

Glad to hear you're up and running.

Nostalgia,
Two Towers is a good DVD to test your sub. Just curious, what kind of IC cable are you using for your Shiva? In the past, I was told about lower frequency signals being less susceptible to EMI so I didn’t worry much about using my budget priced ($12) A.R. subwoofer cable and my Shiva sounded fine. At least that’s what I thought until I stumbled into higher grade subwoofer cables. Recently, out of a curiosity, I looked up some consumer reviews on IC cables and was drawn to a subwoofer cable by Analysis Plus. People say it really makes the difference so I decided to give it a try with a plan to return it if the improvement wasn’t big enough to justify the price tag ($79 for 9 foot cable from Audio Advisor).
If you haven’t, I’ll say Analysis Plus sub cable is definitely worth a consideration. If I own a $99 subwoofer, I doubt that a cable like this would make that much of a difference but for a fine driver like Shiva, higher quality cable will make it even better. Right out of the box, it made the bass smoother and more defined. They say it gets better once broken in. I can’t wait! In Two Towers, when that dragon flies over the marsh land, the whole floor of my apartment was shaking each time it flaps the wings and the sound was so clean! Good news for the tenant below me, I’m moving out in a month. I’m keeping my Analysis Plus cable.


[This message has been edited by Spiker (edited September 23, 2003).]

Spiker,

I'm using a cable I built. It's twisted pair cable with Neutrik Pro-Fi ends on it. Besides that, my cables have a whopping 3' run, so I don't think spending ludicrous amounts of money on them will buy me anything.

So, someone claims a cable will sound better once broken in? I'd be curious to see data on that claim.

-Joe

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Remember the Intellivision?
http://www.gotmaille.com/nostalgia/

Nostalgia,

That twisted pair cable with Neutrik Pro-Fi ends sounds interesting. Would I be able to get some details on this? I would like to try a DIY sub cable. If I do, perhaps I can compare side by side between this and Analysis Plus and post a message about it.

Thanks.

Sure. When I get home, I'll start a new thread with some pictures in the Outlaw to Outlaw section.

All I did was take some MTX twisted pair interconnects I had lying around and snip off the ends. I then bought the Neutrik Pro-Fis and soldered them on. Cake and pie.

-Joe

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Remember the Intellivision?
http://www.gotmaille.com/nostalgia/

Okay, I know I am opening up the dreaded cable topic, but just how does a cable get "broken in?" I mean, how does the molecular structure of the wire change after the first "X" amount of hours it is used so that it is controlled to be "better?" What type of quality control does the wire manufacturer have to make sure that the new cables always behave the same way as they are "breaking in?" Do the electrons really notice the difference? I have a 16' run to my sub, the cost of exotic cables would cost more than the sub, well maybe not more than the sub but you get my drift.

Alejate,

a simple way to settle this argument is to get 2 pairs of same speaker cable and use one pair for a while. Then switch it with the unused pair and see if there are any differences. I have not had the urge to do this because I am content with the cables I have now and if they only get better as time passes (theoretically), I’ll just take that as a bonus.

I do not have the full understanding of speaker cable aging process but even if I do, I’m not sure what I’ll do with it unless I am an audio cable designer working for some John Doe company. However, what I do care to know is which cable will optimize the performance of my audio system and which will be a waste of money. If I am a Ferrari owner, I would make sure the tires on it is compatible which will give the tractions needed to accelerate and turn fast as the car is designed to. On the other hand, if I own a Honda Civic (good car for the price) I wouldn’t spend $2K plus on tires and expect it to run like Ferrari. Optimization is the key here.

By the way, I did hear such terms as copper “oxidation” and “skin-effect”. I’m not sure if those terms are related to your argument.

Oxidation is not part of the "break in" period. I liked your car reference, but again you don't initially change the tires on the day of purchase of the Ferrari. So what is this "break in" period for wires since they have no moving parts nor do they give up any of their property, (you know, laws of matter)? Not questioning different qualities of wires, just the break-in period concept. May be this needs to go to a different thread since it's starting to get off the original topic. And then, what about the break-in period for the wires in the pre amp, and the amp, and the speakers, and the sub's amp and speaker, ... . How long do you wait for all these wires to break-in? How will you know when your speaker wires are broken in since you are not even sure your connecting cables are broke in yet?

There has been a drawn out discussion on bass / LEF level from DVD of Harry Potter, The Chamber of Secrets and LOTR Fellowship of the Ring. What about LOTR, The Two Towers? I was wondering if anyone has noticed any lack of bass / LEF level at the moment of explosion of Helms Deep wall in that movie. It is a visually spectacular explosion but as I watched 3 times with different adjustments on my sub, it all seem to lack the punch that makes the good sub owners smile. Other DVD like Star Wars, Attack of the Clones has that punch, especially at the beginning when the senator Amedala’s shuttle craft explodes.

Would it be that The Two Towers has lower frequency than my sub can respond and end up not being heard during that explosion? I am confident that my sub can do well down to 20 Hz (Shiva driver, 5 cu. ft. enclosure & 150 watt plate amp). Its just my gut feeling that such a scene should really rock the floor but it didn’t which was disappointing.

Any advice on this?

I just popped it in. I have a Shiva III ported sub in an 85l enclosure.

The bass is most definately there. There's a hard, low rumble. It's more feel than sound. I'm only driving it with the 165 watts from my 7100, so I'm sure it should be even more impressive.

It could be like you said, your sealed sub is rolling off down there. My ported sub is tuned to about 21hz, and is -3db down in the teens.

If you're in the NJ area, you can swing by and have a listen. Just bring a good amp

-Joe

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Remember the Intellivision?
http://www.gotmaille.com/nostalgia/

Nostalgia, thanks for the input.

My sub has a 15” passive radiator. According to Adire’s Shiva application sheet, mine (5 cu. ft. box) is tuned to 17.3 Hz. That should be low enough for just about all DVDs.

Yes, the rumble, I can feel it when the wall explodes. If you have Star Wars, Attack of the Clones DVD, try a side by side comparison. I personally think the explosion sound effect is better in Attack of the Clones.

I was just trying to see if there are various settings that one should watch The Two Towers with to optimize the audio portion of it. Or, I thought maybe I missed something.

Thanks for the audition opportunity but I’m in Chicago which makes it little difficult.

Let me know if you find out something else about The Two Towers.