Guys,
Sorry I've dropped out. I have not received any notifications from the site for some reason and thought the thresd dyed out...
Anyway, I'll try to answer all questins I remember:
1. I've made a single-driver speaker more than a year ago and don't have it anymore. I calculated a 2.2 l box as ideal for a ported speaker, but I had a pair of 3 l boxes on hand, so I've used them. Sounded fine by me and the current owner is happy with it too.
2. I've used that notch filter, with exact inductor and cap, but probably 22 Ohm resistor. The sound definitely changed for the better and I've ran the design by the full meeting of Audio Society of NJ, so it's not just my opinion. As I've mention before, the first time I've tryed it, I used a sand-cast "non-inductive" resistor and the notch was lower than intended, (AFAIR around 6.5 kHz). I then used a higher grade (don't remember the brand) resistor and the notch moved into the right place.
3. You can surely measure the effect of the notch if you have a FR measurement set-up. If you don't but have a sine-wave generator and a high-impedance voltmeter, you can hook up the notch to a 16Ohm resistor. Vary the frequecny form around 1kHz to 15 kHz in some small increments. For each frequency measurwe the voltage on the output of the generator (or better an amp) and then (without changing anything) on the + side of 16 Ohm resistor. Divide second by first, take log of that, multiply by 20 - that will be attenuation in dBs. Plot that vs. frequency in say Excel and use log scale for X. Surely, the notch filter will have some broadband attenuation outside of the notch area, but it should be small.
4. I've tryied to model this driver with the passive radiator you mentioned and the rersults looked horrible. I'm not sure if that's the right passive to use. Did you use one or two per cabinet?
5. Damping the ported or passive radiator cabinet should be mostly done on the walls and very lightly in the volume, if at all. However, without any damping it would not sound right in the midrange. At least not to me.
6. As for non-parallel walls - look at the pictures on my web site. BTW, that speaker does not use the notch filter - I worked the elimination of 8kHz peak into crossover. To be honest, I don't think this driver can sound really high-end without a supertweeter.
Vadim
Sorry I've dropped out. I have not received any notifications from the site for some reason and thought the thresd dyed out...
Anyway, I'll try to answer all questins I remember:
1. I've made a single-driver speaker more than a year ago and don't have it anymore. I calculated a 2.2 l box as ideal for a ported speaker, but I had a pair of 3 l boxes on hand, so I've used them. Sounded fine by me and the current owner is happy with it too.
2. I've used that notch filter, with exact inductor and cap, but probably 22 Ohm resistor. The sound definitely changed for the better and I've ran the design by the full meeting of Audio Society of NJ, so it's not just my opinion. As I've mention before, the first time I've tryed it, I used a sand-cast "non-inductive" resistor and the notch was lower than intended, (AFAIR around 6.5 kHz). I then used a higher grade (don't remember the brand) resistor and the notch moved into the right place.
3. You can surely measure the effect of the notch if you have a FR measurement set-up. If you don't but have a sine-wave generator and a high-impedance voltmeter, you can hook up the notch to a 16Ohm resistor. Vary the frequecny form around 1kHz to 15 kHz in some small increments. For each frequency measurwe the voltage on the output of the generator (or better an amp) and then (without changing anything) on the + side of 16 Ohm resistor. Divide second by first, take log of that, multiply by 20 - that will be attenuation in dBs. Plot that vs. frequency in say Excel and use log scale for X. Surely, the notch filter will have some broadband attenuation outside of the notch area, but it should be small.
4. I've tryied to model this driver with the passive radiator you mentioned and the rersults looked horrible. I'm not sure if that's the right passive to use. Did you use one or two per cabinet?
5. Damping the ported or passive radiator cabinet should be mostly done on the walls and very lightly in the volume, if at all. However, without any damping it would not sound right in the midrange. At least not to me.
6. As for non-parallel walls - look at the pictures on my web site. BTW, that speaker does not use the notch filter - I worked the elimination of 8kHz peak into crossover. To be honest, I don't think this driver can sound really high-end without a supertweeter.
Vadim
Hi Vadim,
I'm not the OP, but would (2x) the passive radiator, say mounted on each side "model" better than a single?
Also, what type of supertweeter (or tweeter) are you using in your setup and if not proprietary can you share your crossover?
Thanks
1. Please, post the model of the passive radiator again, I don' have it handy. If you have parameters: Vas, Qm, Fr - that would be even better. I'll try to quickly model that again.
2. The supertweeter I've used is LCY K100.
3. The XO between one of the Audiences and the LCY is 1st order series. The second Audience is used for baffle step compensation. So, for a single driver you really need to use the BSC circuit. Otherwise, the bass will sound weak and the upper mid-range would shout at ya...
As for sharing the XO values - I spent close to a year on it and am offering these speakers to some people at the moment, so I'd prefer to keep it to myself for now. It may change in the future, as I've done before.
Vadim
2. The supertweeter I've used is LCY K100.
3. The XO between one of the Audiences and the LCY is 1st order series. The second Audience is used for baffle step compensation. So, for a single driver you really need to use the BSC circuit. Otherwise, the bass will sound weak and the upper mid-range would shout at ya...
As for sharing the XO values - I spent close to a year on it and am offering these speakers to some people at the moment, so I'd prefer to keep it to myself for now. It may change in the future, as I've done before.
Vadim
just before I hop to bed: here I posted the results of the measuring of the speakers:
http://www.diyaudio.com/forums/full...ed-nearfiel-plus-subwoofer-2.html#post2785756
http://www.diyaudio.com/forums/full...ed-nearfiel-plus-subwoofer-2.html#post2785756
maybe interesting: freq response compared between what audience says and what I achieved in my 2,3 liters enclosure:
An externally hosted image should be here but it was not working when we last tested it.
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