Contour Enthusiasts Group Archives Forums Modifications Audio Vifa 7" owners:how much are you driving them with?

I was just curious what kind of amp power you guys are using with your Vifa PL-7's.

I'll be running these down to around 40Hz without a dedicated sub to start with, and know that with their relative lack of efficiency, a 4x50(rms) prolly isn't going to cut it for proper low frequency performance.

I'm asking because I'm gunning for a 4x100(rms) amp, but since I'm looking to do crossovers before or at the amp, that's eating into the budget. I'm looking for healthy volume levels, fwiw.

Any comments or suggestions would be most appreciated.

Dan - working on the adapters now

I would be willing to bet that 50w would be plenty of power. I believe Luke is using ~50w on his, he may be able to give you a review of the bass performance. 40 hz may be a problem, though. They have a fair amount of excursion, but the power will have to be relatively low to allow you to go down to 40 hz.

I'm using an Alpine F407 to run the Vifas and the Neo8s right now. 140W x 4, or about 75W x 4 rms. I wouldn't want to give them too much more, as they are fairly efficient and allow me to set the gain fairly low. I have them crossed at 60Hz, and they don't seem to have any major weakpoints in thier current range (60-4000Hz) I'll eventually be using them to cover 60-800Hz, and have the Neo8s cover 800-6000Hz, allowing them to truly shine.

I wouldn't cross them over under 60Hz, for that I'd look into a larger driver

I haven't decided yet on mine (the PL's should be here next week). I'll either:

(1) Go active with an Audiocontrol 2XS and bi-amp the components using a 4ch amp. Each driver (2 mids, 2 tweets) would get 85w.

(2) Bi-amp the components but use passive crossovers, so each driver would still be at 85w.

(3) Bridge the 4ch amp to 2ch and put 290w per channel to the components (using passive crossovers).

(4) Run the components off the front channels of the amp and leave the rears to run the sub. They'd get 85w per channel to the components (using passive crossovers).

I dunno.

Thanks for the feedback, guys. Looks like I'll go with the mtx thunder 564 and dedicate each channel for a PL-7. Any comments on that one or something better for not a lot of scratch? ($300 on fleabay is about as high as I want to go.)

Just so I'm clear on this, the Audiocontrol 4XS can be used to set a midpass for these, right? I'm wanting to stay with 4 independent channels in order to use the spiffy time correction stuff in the Alpine HU. (Just picked up the 7995 yesterday.) I'd really like to go with the DXS, but two of those would be spendy. Next month, I'll add the tweets and an amp for them.

Thanks again!

Dan - finished the apeaker adapters today. Easy-peasy with the right tools.

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Looks like I'll go with the mtx thunder 564 and dedicate each channel for a PL-7. Any comments on that one or something better for not a lot of scratch?

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I would say go for a US Acoustics USX-4085, which can be had at www.thezeb.com or www.sounddomain.com for about $175, but they appear to be on factory backorder.

There are soooo many good 4ch amps out there that can be had for under 3 bills. Just off the top of my head, you can get a new Kicker KX800.4 for $260-ish or a KX600.4 for $185-ish.

Thanks Cthomp, but I should've said I'm looking for a higher-end amp.

I had a bad experience with an Alphasonik once, so I won't be trying the US Acoustics. Kicker's listed SNR ain't so hot.

Thanks anyway. (shrug)

Oh - any danger in running freq's above 6k to these? I'm thinking if the amp comes in much before the xover, I could just use the high pass crossover on most amps set at 60Hz and let the Vifa handle/ignore anything over 6k.

Appreciate all the info,
Dan

Take a look at the F407, it's a couple years old now but in terms of ability and sound it's still a fairly impressive amplifier. Also it has a very comprehensive crossover network, which would allow you tune a 2 way system without an external crossover. I have a 4XS but haven't set it up yet. In the meantime the amp's crossover is doing very well.

You can set the levels at anywhere from 40Hz to 8000Hz. That way you would avoid sending the Vifas anything over 4000, which is where you should really be cutting them out anyways (I would recommend the cutoff point be lower than that too, but it's more than adequate as a temporary setting)

Thanks HTM! I wasn't aware Alpine offered a high-end amp with that useful of a crossover setup. Cool!

No current fleabay listings for the one you mentioned, but it looks like the current mrv-f540 can be had for around $330. I can swing that, but it may be a couple of weeks before I can do it.

Thanks again,
Dan

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Thanks Cthomp, but I should've said I'm looking for a higher-end amp.

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A watt is a watt no matter whose name is on it. And, unless truly ridiculous any noise in the system will be undetectable to the human ear.

The "perceived" difference between "high-end" amps and the reasonably priced stuff (let's forget the flea market stuff) is the power ratings. Those "high-end" amps will typically put out quite a bit more than what they're rated for, while the value-priced stuff (like JBL, US Acoustics, Lanzar, etc.) will be pretty much spot on with their ratings.

This is the difference why someone might "hear" a difference between a 100w x 2 US Acoustics amp versus a 100w x 2 PPI amp. The PPI amp might be producing twice its rated power while the US amp is pushing what it's rated for.

In short, it all really boils down to actual produced watt per dollar to figure out which amp is the winner. A US Acoustics amp that produces 200w x 2 versus that PPI amp might cost half as much. Put that $$$ you saved towards more goodies for your system.

BTW, have you checked Alphasonik's latest product line? It looks very impressive. I'm not quite sure what the latest relationship between US Acoustics and Alphasonik is. I haven't been able to figure it out.

Anyways, enjoy your PL's and try not to throw away money needlessly.