*** Adire Tempest active crossover ***

[beatrix_choice]

Hi everybody,
I'm Luca from Italy and I would like to pick your brain on a few questions.
First of all a little background, my system:
- source (CD player/turntable)
- Harman Kardon HK970 stereo integrated amplifier
- Harman Kardon PA2000 stereo power amplifier
- DIY Loudspeakers (bass reflex, 45 liter cabinet, tuned to approx. 50Hz) with Fostex FE206E fullrange driver + Fostex FT-17 supertweeter
- DIY Subwoofer (closed, 70 liter cabinet) with Adire Tempest Dual Voice Coil driver

After building the loudspeakers I have realized that I love the fullrange extra-bright, analytic sound but the listening definitively lacks bass frequencies. The subwoofer seemed to be my best choice and after some lurking here and there I have decided to buy Adire Tempest DVC driver that was readily available in my favourite shop in Italy.

Keep in mid that:
i) the 100W HK PA2000 power amplifier is stereo and will drive the two Tempest voice coils separately (8 Ohms each voice coil)
ii) the signal to PA2000 comes from the Pre-out of the integrated amplifier with a +/- 3dB regulation

Now the sub cabinet is ready and I need to filter the sub.
My goal is to melt the sound from the sub and the loudspeakers and I suppose I should undergo some trial and error with cutoff frequency.
But trial and error with passive crossover (even with a simple 2nd order filter, where the inductance for 70Hz cut wheights 1 kg and cost 25 euro) is quite expensive/unmanageable.

For this reason I would like to buy a "ready made" active crossover or, at least, a kit (PCB + components) since I'm not so skiled in building electronics.
The basic feature should be adjustable cutoff frequency to play with.
Subsonic filter, phase adjust and gain, albeit being considered desiderable icing on the cake, could not be present.

Any suggestion on which filter will do the job?

Additional questions:
1) do you see any problem to drive each voice coil of the Tempest with L and R stereo signal, i.e. driving a sub in stereo mode?

2) what about Harrison Labs LP1 crossover? (http://www.hlabs.com/products/crossover). The output of LP1 is a double low pass mono-mix signal, this means that the input stereo signal will be filtered to the desired cutoff frequency, summed and splitted into two identical mono signals?

2 bis) Using this crossover I will feed the each Tempest voice coil with two identical mono signals. Do you see any problem doing this?

3) another option would be a Behringer CX 2310 Crossover (http://www.behringer.com/CX2310/index.cfm?lang=ENG) but it seems overfeatured. What do you think about this option?

Thank you for your interest

Luca

 

[Peter Menting]

Luca;
You might consider these people; www.marchandelec.com. The kits are easy to assemble and relatively inexpensive. The crossover frequency can be adjusted with small plug in modules. They also sell a power supply to drive the boards---total price for two boards and PS is below 100 US. Hope this helps.

Pete

 

[dangus]

The Behringer is good value for money, and it's adjustable.

Or... you could temporarily use a computer sound card to implement an active crossover, determine the best frequency and slopes, then order a Marchand kit.

 

[beatrix_choice]

Thank you all,
but the sub exit of the CX2310 is one channel mono, therefore I should use the LOW stereo exit (filtered), right?
I'm again on the subject:
do you see any problem to drive each voice coil of the Tempest with L and R stereo signal, i.e. driving a sub in stereo mode?

Thank you

Luca

 

[zobsky]

Thank you all,
but the sub exit of the CX2310 is one channel mono, therefore I should use the LOW stereo exit (filtered), right?
I'm again on the subject:
do you see any problem to drive each voice coil of the Tempest with L and R stereo signal, i.e. driving a sub in stereo mode?

Thank you

Luca

The sub output on that crossover is summed ie (L+R), Its probably easiest to just drive both VCs in parallel with one mono amplifier, .. but if you did want to run both channels,.. just split the signals using a simple Y splitter.

 

[beatrix_choice]

You mean simply splitting Behringer XLR sub output to 2 RCA connectors?
i.e. using a female XLR-->female RCA adapter + a Y cable "male RCA"-->"2 male RCA"?

The mono amp idea is not suitable since I already have a good quality stereo Harman Kardon PA2000 amp.

I was wandering if running a DVC in this double mono way (or in stereo mode using another active crossover, not the CX2310) would be reccomended.

Thanks

 

[zobsky]

You mean simply splitting Behringer XLR sub output to 2 RCA connectors?
i.e. using a female XLR-->female RCA adapter + a Y cable "male RCA"-->"2 male RCA"?

The mono amp idea is not suitable since I already have a good quality stereo Harman Kardon PA2000 amp.

I was wandering if running a DVC in this double mono way (or in stereo mode using another active crossover, not the CX2310) would be reccomended.

Thanks

Yes, I have the same model X-over, and that's how I used it when I wanted to power both VC of my shiva ( built up some XLR to RCA cables, and split the RCA mono to two signals via a Y adapter).

Yes, you should be able to use both channels of your PA2000. Just be sure they both work identically and don't have uneven DC offset or other nasties.

FWIW, .. my CX2310 works fine but the switches have become kinda noisy and the unit sometimes needs to be slapped about to wake it up, even though I've never really used it extensively, .. maybe bad manufacturing quality? Not bad for the price, though.

 

[beatrix_choice]

Thanks,
how I can measure DC offsets and what could be "other nasties".
As measure instruments I have a PC with soundacard and access to (quite) every kind of software (a friend of mine works in a digital recording studio and another one in a cellular phone/electronics repair shop). I also have a professional Fluke multimeter.

Thanks

_luca

 

[zobsky]

Thanks,
how I can measure DC offsets and what could be "other nasties".
As measure instruments I have a PC with soundacard and access to (quite) every kind of software (a friend of mine works in a digital recording studio and another one in a cellular phone/electronics repair shop). I also have a professional Fluke multimeter.

Thanks

_luca

http://www.stereomanuals.com/articles/glenn-mcdonald_dc-offset.htm

Hope this helps

 

[beatrix_choice]

The Behringer is good value for money, and it's adjustable.

Or... you could temporarily use a computer sound card to implement an active crossover, determine the best frequency and slopes, then order a Marchand kit.

Hi all,
wich software can I use to implement an active crossover.
Experimenting: this seems an amazing way to spend sunday morning...

Thank you

_luca