Jeffrey Stanton

Can anybody take a look at the above post and see if there's poosibly a voltage/impedance mismatch between my LFE and the Mackie amp?

Thanks,

J Stanton

Craig Woodhall

buddy, i was running a Mackie FR-1400 to a variety of subs, and it worked flawlessly. imo, you are wiring it up wrong somewhere down the line.

If i were you, forget the 3 sub outs. run the mono subwoofer output to one input on the back of the Mackie. wire the Tumult in series for a 4ohm load and then bridge the mackie and run it to the Tumult.

Craig

Jeffrey Stanton

The answer appears to be "none of the above". I undid everything, & hooked up the sub again EXCEPT I used a Pioneer C-60 pre-amp in conjunction with the Mackie. This time it worked. The number of sub inputs I tried to use has absolutely nothing to do with it.

Maybe someone can explain why my sub/amp needs a pre-amp and evidently no one else's around here does.

Thanks for your response Craig

Dan Hine

Pro gear typically needs a higher input voltage than home audio gear puts out. You need a preamp to boost the signal from your Yamaha. Also, I'm assuming that you have the gain knobs on the Mackie turned all the way up. If not, you should.

- Dan

I strive to be the man my dog thinks I am.

Jeffrey Stanton

Thanks Dan:

The gains on the Mackie are turned up all the way, and the volume control on the Pioneer pre-amp needs to be 3/4 to ALL the way up (or somewhere in-between) to get the little red lights on the Mackie to come on occasionally...

Dan Hine

Hmm...you don't really want your red lights to come on. Unless it's just a flicker during a very bass heavy scene. Anyhow, with the preamp in place are you getting bass response you're pleased with or are you still having troubles?

I strive to be the man my dog thinks I am.

Jeffrey Stanton

Hey Dan:

I've been adjusting the frequency of the flashing of the red lights with the volume control of the pre-amp so that they only flash occasionally with music and with heavy bass scenes, like you indicate. I know that they're clip indicators so you do not want them "on" all the time...I guess the question is where exactly do I draw the line as to their frequency.

With the pre-amp in place I was a little surprised at having to have the volume control up to 3/4 or even as high as all the way up (depending on the source).

But the response is quite adequate, using the performance of the AV-15 with the Rythmic Audio as a reference (which I was using before the Tumult). Like Kyle Richardson told me, it isn't a night and day difference, but the SPL is a bit greater with the Tumult, and I had added 600 gms to each of the PRs so the Tumult sounds a little different(lower).

As it turns out it looks like I was running the previous driver (the AV-15) as a 2-ohm load with the Rythmic amp because there was no jumper connected to the inputs. I think I was probably sending the AV-15 a lot more than the 380 watts I thought I was (Brian Ding, are you out there to comment on this)?

Jeff S.

JesseSilver

>>As it turns out it looks like I was running the
>>previous driver (the AV-15) as a 2-ohm load with
>>the Rythmic amp because there was no jumper
>>connected to the inputs. I think I was probably
>>sending the AV-15 a lot more than the 380 watts
>>I thought I was

I'm not Brian, but I'll offer my thoughts. I received an AV12 last week that I briefly tested with my multimeter. It's a Fluke 87III, so it's really accurate and I completely trust it's measurements. The AV12 I tested (which shares the motor assembly with the AV15) had a DC resistance of about 1.6 ohms across each of it's two voice coils. This is even less than the 2 ohms it's supposed to be, but not a problem if properly hooked up in series to yield a bit over 3 ohms. You were pushing that 380 watt (at 4 ohms) into less than two ohms, so the wattage could have easily gone to 700+ watts, and frankly I'm a bit surprised you didn't ruin the amp as well. The fact that you ruined the driver isn't a big surprise. You were pushing those 700+ amps through only ONE of the voice coils, so assuming each has the ability to dissipate a certain amount of power as heat, you had half as much heat dissipation capability as you normally would have. In series, all circuits have the same current, so your current wasn't higher than it would have been, except the wattage probably doubled, so I'm not sure what effect that had on the current.

Summary? I seriously seriously doubt you would have had any problem running that AV15 with the rythmik amp if it had ben properly wired. Plus, it would have sounded awesome, whereas you only had one magnet hooked up so it was as if Stryke had designed the AV15 with half as thick a magnet and half as long an active voice coil! Not good for sound...

I really hope people read this whole thread because anyone stopping on the first post will get a very negative impression of Rythmik and possibly Stryke, neither of which is at all warranted (in my opinion)

Oh, and with regards to the Mackie... are you at all familiar with -10/+4 ? Pro and consumer gear output and expect input at very different levels, much to the dismay of people who try to mix pieces together. I suspect you are one such person, as your Mackie probably expects inputs at +4, and your sub output is probably at -10. The 14 db difference is easily audible (as 10 db sounds, more or less, like half the volume), so the preamp is necessary to make up for this level difference. This is just a guess, though... I have a lot of recording studio experience, but it's been a while

Brian-K-Owens

"had a DC resistance of about 1.6 ohms across each of it's two voice coils. This is even less than the 2 ohms it's supposed to be, but not a problem if properly hooked up in series to yield a bit over 3 ohms."

DC resistance of the coil is less than the impedance of the coil. When you send an AC signal through the sub, the impedance will change with frequency.


I could not tell you if that amp can actually double its power at 2 ohms. I am not trying to sound negative about the amp; I have never used it, but if it can double its power at 2 ohms, then there would be a good chance the mininum impedance rating would be less than 4 ohms, so I doubt he was actually driving the sub with 700+ watts. I could be wrong. . . .


I have never met Jeffery, but I am the reason he began to raise such big concerns over the AV-15 sub. I feel strongly that he has a valid agruement as to his driver failure, and I told him so in an email, as what I had to say I did not want to spread all over a public forum. I will also say that I am not being negative about the AV-15; it is a GREAT driver, and I will continue to buy them in the future, but in his case it is possible that the driver failure was not his fault. . .even if he did not connect it properly.

Brian

Brian Owens

Jeffrey Stanton

Just a little "heads-up" for Stryke/Acoustic Visions re: instuctions for hooking up an AV-15 sub. It would have helped a lot and in fact may have averted this whole mess if they (someone) would have included a note or something with the shipped sub with some brief instructions as to how to hook the driver to a given amp.

In all fairness, I do recall John J. briefly going over some wiring instructions with me on the phone one morning. When I finally did get the sub some weeks later, but not having a xerox copier for a brain, I must have forgotten the "jumper" part. And I could not see inside the sub to see how it was wired. As there was no jumper or instructions included, the first thing I tried (as I recall) was to connect one driver lead to the (+) on set of posts and the other lead to the (-) post of the other set. As I got nothing from that, I tried the (+) and (-) of ONE set of posts and got PHENOMENAL bass output. For a couple of weeks, anyway, then things started going sour after a couple of DD/DTS heavy bass scenes.

That AV-15 is right up there with the Tumult in performance, no matter how I had it wired. For the price, it wins handsdown in the bang/$ competition.

And the Rythmic amp performed extraordinarily well considering what was being asked of it!! Yow.

But the whole point of this is that some brief WRITTEN instructions would have done a world.

Sorry for any misunderstandings,

Jeffrey S.

JesseSilver

Please don't take this post as a flame! I only speak my opinion (not Stryke's) and it is not intended as anything personal.

My opinion is that while instructions would have been a nice bonus, they should by no means be expected for a product as standard as a speaker. Sure, including the specs may have made sense, but I see no more obligation for them to include instructions on hookup than instructions on box-making for the driver. The idea is that it is a DIY product and that someone buying it is assumed to either already know how to use the product, or to take some risk in learning on that product. There is nothing odd about the AV15 or it's two voice coils. I've never built a DIY speaker, but I'm aware of parallel and serial hookup, so there should be no problem. Instructions may have helped, but being as there is nothing "non-standard" about the way they wired their speakers, I feel like this is something nobody should expect.

Just my two cents, and I could understand how somebody in another position would think differently... my comments are not means personally.

Like Brian said, though, I agree there could have been something wrong with your driver anyway.

Jeffrey Stanton