help on full range drivers .. need to buy quick!

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Have no experience with panasonic receivers, I do have good experiences with other panasonic products(better than sony!).

But I find the sonic-impact T-amp sound the poorest of all Tripath chip based amps..... and since many of my friends have a lot of different Tripath chip based amps I've heard a lot of them.....

But why use a receiver in the first place, seperate components always have my preference (separate amp, separate tuner and separate dolby decoder, makes it a lot easier to experiment, learn and know the weakest link in the chain....)
 
don't worry

i only use seperate highest quality possible components....for myself :p

but this is a project for a friend ( couple )
wich needs to be as simple as possible to use
look good, cost not much
and THEN sound good

so ... u see that i have a lot of problems before getting in the audio realm :p

then again

i have just looked at the panasonic receivers ...
the most expensive one, wich is not quite expensive
doesn't seem to have pre-outs
wich sucks

then the figures of audio seems nice,
but it's quoted in 6ohm ( why they do that for home consumer products? ) wich makes me think that they aren't beeing straightfoward
and then the "digital amp" :p

you say that it sounds nice?
i wonder compared to Harman Kardon
wich i was looking at
( nice complete units + serious looks )


the other optiong we have is to get
a cheap one, like basic kardon units at 250$USD
and use the outputs to drive an amplifier
like my bryston 2B i could sell him
 
The last option sounds like a good idea!
That way you will be able to do the appropriate filtering.

Don't know though how the quality of harman kardon is these days , I used to get a lot of them back from some series (especially models with a lot of digi in them) (and we were (couldn't) never honest about this to the customer offcourse.....).

Maybe they use class D in them nowadays ;-)
Things develope so quickly...

The 6 ohm limitation on the panasonic gives me the feeling the power-amp inside isn't very good in quality, besides it would limit options in this system indeed.

Maybe you have (your friend has) very different taste than I do, I like bass to give that "punch on the chest" feel without sounding exaggerated. And in the mids I like honesty and realness, in the highs I like "smoothness", "silkyness" and not -as we would call it in our shop- "pisssssss". The audiodigit amp improved on every aspect I like and made this possible with the same loudspeakers!*

Your friend is most likely to "fall in love" with this "good looking" system if there can be listened to for extended periods of time.
So I would advise -since you probably have pretty spoiled ears- to have a good listen to the (especially mid and high range, because the briston is most likely to be the better lower-end driving amp) receiver first.

Things are still not clear to me, why a receiver? Does it have to have a radio? Does it have to have dolby? Or will a basic remote controlled integrated amp do? And how many sources will be connected?

One very important thing, I almost overlooked the sub!
Adding a filter to cut the lowest frequencies on all the veravox drivers can help a lot on improving the max. accomplishable sound pressure level! They won't produce anything good under 80 hz anyway. The crossover frequencies from my earlier post (150 hz and 500 hz) were estimated by the way, just keep the idea of using only one driver for the main treble and filter the rest to make it fit well in the room and to your friend's taste.

I have good experiences with a capacitor in series of 500 nanofarad(mkt) and a resistor parallel of 5 Kohm on the input of the amp. Buying 10 150nF capacitors and a couple of resistors in different values you can make it work.
Don't know how good you are at this, but I can make a schematic for you to start from when you have made your mind up on the amps... The eventual filter can consist out of 2 caps and two resistors per channel and will act as a band-pass filter (except for the one that goes all the way up).

I just found this thread of interest:
http://www.diyaudio.com/forums/showthread/t-56701.html

Maybe passive filtering the speakers(on the power amp's output) and using only the briston is a better option. Keep in mind though that caps and coils(used in this type of filtering) will be more expensive.
And the future options with this system will shift into another direction..
I would rather invest in good amplification than passive (loudspeaker) components. They exist in cheap qualities, but because of higher currents involved the signal benefits a lot from using good quality components.

An other idea:
All sources on a passive switch and, split the outputs to two amps after being filtered.
Or better:
Use an integrated amp with pre-out, split the pre-out and connect to the internal poweramp and a second amp after being filtered.
This way you can control volume easier.

But when using the most basic harman kardon:
The sub, the briston filtered 80hz to say 1Khz on 7 veravoxes and the internal poweramp filtered from 80hz and up driving one vervox.

*sorry for the laymen's terms, but have to have words to describe...
 
JinMTVT said:
VeraVox 3, ... what do you guys think ?

Since you have already bought them, just some comments. Sound quality wise I find them on par with the Fostex FF85K, but the small VIFA is better. Out of those three the Veravox can definitely move the most air.
If you have looked at the CSD, there are some hefty resonances at the top (metal cone!). The german import recommends to soften them by putting one of those self-adhesive soft plastic pads of ~4 mm dia. (as used on glass cupboard doors or between glas table tops and their frames) on top of the dustcap. I´m not joking here, it´s a serious recommendation. That way the top should be softened just right.

For straightening out the mids a parallel notch filter of 0.39mH/10uF/5,6 Ohm in series with the driver is recommended. Whether it´s desirable depends much on the baffle width. So may be you don´t need it in your application.

Rudolf
 
hey i have to say thanks again guys ..

i will look into all that as final touch!

moving air IS important in this application
since focus is on voice and effects for home theater !!

what is the object you are talking about for softening the top ? i don't know this object!!
 
JinMTVT said:
what is the object you are talking about for softening the top ? i don't know this object!!
I have them on my desk - but 7.5 mm dia.. Unfortunately I will not travel to Canada this year ... maybe next. :D

So I´ll try to explain: Mine are flat (1.5 mm) transparent circular silicone-like pads with a gluey back They come on a foil were you peel them off. Look for 3M Bumpon, but the very smallest ones.
 
Are those the pads that say "UV protection" on new sunglasses?
Funny the way they "suck" themselves onto smooth surfaces without "glue".
Can imagine they dampen the resonances very well, still keeping the cone light.
And indeed the whole surface doesn't have to be covered in order to dampen good enough, most effective way is in the middle of a surface where the partitial resonance is heaviest(the "top" of the wave...).
I think that a small self adhesive felt pad would work as well...
Good input Rudolf! I'm not surprised by this kind of a solution at all, manufacturers have come up with more awkward ideas!

And about the notch-filter, judge with your ears....

I would figure the build in a large surface will amplify the bass, the highs are most likely to be weaker and the single speaker producing the highs (after filtering the way I previously suggested) can also be notch filtered in the signalpath. A notch filter in the speaker line has to consist out of very expensive components because of the lot of them placed in series with the signal and the losses accompanied by that. Read:http://www.diyaudio.com/forums/showthread/t-60187.html

Very important to keep in mind the drivers will probably sound harsh in the mids and highs before they've had a long break-in period!

Do all this kind of tweaking in time indeed, making it function more or less as a point-source would be more on my list of priorities...
 
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