Hi,
I have a pair of active Tascam VL-A5 monitor speakers and I really like them. But they are quite small and their bass response isn't really good (the frequency curve drops from about 100Hz).
That's why I would like to add a subwoofer to my system.
I need an active sub with a line in and (filtered) line out, like the Tascam LF-S8.
My sound source will be connected to the sub, and the line out of the sub will be connected to my monitors.
But I recently found a very cheap Sony SA-W505. It has some nice specs, and it has a line in and line out. However, the line out is not filtered. It just passes the input signal.
Will it sound bad if I use the sub without filtering the line out (so both the sub AND the monitors will put out the low frequencies)?
Is there an easy way to filter the line out? I think it is a buffered line out with an opamp, so if just add some caps, will that do the trick?
Thanks,
Psycho
I have a pair of active Tascam VL-A5 monitor speakers and I really like them. But they are quite small and their bass response isn't really good (the frequency curve drops from about 100Hz).
That's why I would like to add a subwoofer to my system.
I need an active sub with a line in and (filtered) line out, like the Tascam LF-S8.
My sound source will be connected to the sub, and the line out of the sub will be connected to my monitors.
But I recently found a very cheap Sony SA-W505. It has some nice specs, and it has a line in and line out. However, the line out is not filtered. It just passes the input signal.
Will it sound bad if I use the sub without filtering the line out (so both the sub AND the monitors will put out the low frequencies)?
Is there an easy way to filter the line out? I think it is a buffered line out with an opamp, so if just add some caps, will that do the trick?
Thanks,
Psycho
You could consider something like this: Parts-Express.com ? Harrison Lab ? In-Line Crossovers, Line-Level Attenuators, High Pass Crossovers, Low Pass Crossovers
Most of the plate amps PE sells have a first order 125Hz filter on the lineout. Perhaps those more readily available to you have similar characteristics.
Most of the plate amps PE sells have a first order 125Hz filter on the lineout. Perhaps those more readily available to you have similar characteristics.
This seems to be a real budget problem, so the answers I will give is in consideration of ultra low budget.
First: Just add a sub and run the monitors full range. I would do this first and see what the result is. You are running them full range now.
Second: Buy a real crossover. Something like the analog Bheringer. Yes, it works fine at line level. Then any old sub will do as long as you can bypass or turn higher the crossover.
Third option: Considering this is the DIY forum. BUILD your own analog crossover. It is easy. If you are creative it can be cheaper than even a used Bheringer.
Fourth option: Many of the car crossovers are not that bad. Most are only third order, but so are most plate amps. So a car crossover feeding the monitors and the plate/crossover feeding the sub.
I would not just add a cap to the input of the monitors. A first order won't do much and if it is not buffered, can cause considerable distortion. If you add an op-amp, that means a power supply, and you might as well add a couple more caps and you are doing option three anyway!
First: Just add a sub and run the monitors full range. I would do this first and see what the result is. You are running them full range now.
Second: Buy a real crossover. Something like the analog Bheringer. Yes, it works fine at line level. Then any old sub will do as long as you can bypass or turn higher the crossover.
Third option: Considering this is the DIY forum. BUILD your own analog crossover. It is easy. If you are creative it can be cheaper than even a used Bheringer.
Fourth option: Many of the car crossovers are not that bad. Most are only third order, but so are most plate amps. So a car crossover feeding the monitors and the plate/crossover feeding the sub.
I would not just add a cap to the input of the monitors. A first order won't do much and if it is not buffered, can cause considerable distortion. If you add an op-amp, that means a power supply, and you might as well add a couple more caps and you are doing option three anyway!
"A first order won't do much and if it is not buffered, can cause considerable distortion."
Really?
The JBL BX63, Dahlquist DQ-LP1, etc. are all passive high-pass.
" The Dahlquist unit wiped out all the competition...no grain, no audible distortions or colorations" (review by Absolute Sound)
https://sites.google.com/site/mpbarney/home/dahlquist-dq-lp1
http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/UREI-%20BX63A%20ts.pdf
And of course Nelson Pass:
http://www.passdiy.com/pdf/phasecrx.pdf
Really?
The JBL BX63, Dahlquist DQ-LP1, etc. are all passive high-pass.
" The Dahlquist unit wiped out all the competition...no grain, no audible distortions or colorations" (review by Absolute Sound)
https://sites.google.com/site/mpbarney/home/dahlquist-dq-lp1
An externally hosted image should be here but it was not working when we last tested it.
http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/UREI-%20BX63A%20ts.pdf
And of course Nelson Pass:
http://www.passdiy.com/pdf/phasecrx.pdf
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You're right about the low budget
I was thinking about building a crossover myself. But I don't have the tools to make a proper circuit board, so I guess I will need a kit, I'll search some more for that.
The Behringer crossover is a good option too but it's quite hard to find a used one here, and I'm not gonna buy it new: for that money I'd better buy a more expensive sub...
I'm not gonna get involved in the passive filter discussion
But I was thinking more about modifying the subwoofer electronics: If the sub has buffered line out stage (opamp?), isn't it just possible to add some parts to the output stage like in a real active crossover circuit? Active filters are just opamp stages with some caps around them. So just adapting the subwoofer line out from a full range stage to a filtered stage, would that be possible?
You're right about the low budget
SNIP...
But I was thinking more about modifying the subwoofer electronics: If the sub has buffered line out stage (opamp?), isn't it just possible to add some parts to the output stage like in a real active crossover circuit? Active filters are just opamp stages with some caps around them. So just adapting the subwoofer line out from a full range stage to a filtered stage, would that be possible?
The "Active Filter Cookbook" by Don Lancaster is a good resource.
It is all over the net in .pdf form now.
My copy is all worn out.
.
Years ago I built a State Variable filter using TL082's (actually TL084 quad Op-amp) and it worked great.
Dave
Anything is possible with enough time, knowledge and money.
With crossovers going for as little as $25 used at places like Music Go Round and on Craig's list, spending hours figuring out how to DIY, locating and purchasing the various parts does not seem so cost effective.
I sit most nights listening to an 18 inch sub playing full range music.
Obviously the highs are a bit lacking but its passable.
Look up Sallen and Key and Butterworth op amp filters.
Not true!
The monitor speakers (Tascam VL-A5) do feature a low cut filter, but cutoff frequency is 500 hz! I have no idea why that frequency is so high, but it's way too high if you're just adding a sub!
The LF-S8 has an indepent crossover. It has stereo HF outputs (for the monitors), and an LF output for an extra sub. When using the LF-S8, there is no need to use the low cut on the VL-A5s.
Might be a typographical error, Donkey Kong was supposed to be Monkey Kong...
Have you tried the "500 Hz" low cut switch to hear if it might be a mis print of a 50 Hz cut?
Thinking about it, a 150/80 Hz "LF contour" would make sense, 150/800 Hz not very much, one seldom sits down in front of a pair of near field monitors and says "sounds good, if only for that midrange bit around 800 Hz being 1.5 dB too much..."
If they were my pair, first thing I'd do is make sure the volume pot was labeled "0-11".
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I tried it, and it's definitly not a 50 Hz cut. I can hear it clearly cutting @ 200 Hz, and I can hear it has a minor difference @300 Hz. It's difficult to A/B test it because the dipswitches are very hard to reach.
The 800 Hz is, as far as I can hear, right too.
It would also be strange if Tascam, not an unknown company, would write the specs wrong on the product itself, in the manual, and on their web page, for 2 generations of an entire monitor range (VL-X* and VL-A*).
But I still wonder why they have chosen a cutoff frequency that high...
The marketing blurb with the speakers says its for use with the LF-S8.
Why I said "Apparently". Doesn't make a lot of sense, manual is rubbish.
Neverless it should work well with two subs, stereo or mono, set quite
high, the high x/o point maximises the available volume capability.
Or double the capacitor values in that part of the circuit.
rgds, sreten.
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