This is a spin off thread, to avoid thread pollution.
Here I'm going to discuss and present ideas for creating a basic clone of the IDS-25, with a few twists, to use for GF's HT front mains.
First, when considering clones of the IDS-25 system, it's a good idea to be familiar with the original! This is the main page, and much more info can be found from other linked pages:
Russell either had a custom driver built, or was very careful in selecting the driver which he uses. It's not a simple challenge, as one is looking for wide frequency extension, low distortion, and freedom from any high Q break up modes in the top end. I like his approach for the equalizer, but then, like Russel, I'm kind of old school myself, and would do it pretty much the same say - including balanced inputs and outputs available, low noise, low distortion op amps, film caps, etc. :T
Most of the IDS clones I've read about, including Javier's, are somewhat flawed due to their choice of driver, usually made on the basis of cutting cost.
BTW, this Vifa TG9FD-10-04 is purported to be the driver used in the IDS-25. Verified on several sites.
It does use a copper cap to limit impedance rise and upper end distortion, and the cone resonances are well damped.
With the shown driver Fs, they will need some significant LF EQ to perform below 100 Hz. BUT, the sensitivity gain should be high; not really all that much power. Xmax is rated at 2.6mm- not very high.
Still, I'm tempted as a giggle to build some new mains for my GF's family room HT with these, see how they sound. Its a fair sized room, about 18' by 30'.
It's certainly worth running some numbers and modeling. But I would recommend using these like the company below, with a some extra LF reinforcement. I like the physical design because it appears well optimized for achieving good Sd relative to the driver area, and of course, you can pack these together. Front panel design and routing will be an issue- might have to go to phenolic panels, maybe even aluminum.
Interesting... let's see, 50 at $19 each is still pretty close to $1K. Still not an impulse purchase.
Good first step would be to buy a few and see how the distortion measures at low drive levels, and how that would scale with an array to 90 dB level baseline.
*****************************
Geez, another distraction from current projects. Just ordered 4 for testing.
I ran the numbers, and using a configuration of 25 on each side, with five sets of drivers wired in series and then paralleled (a 5 x 5 matrix) with the net efficiency gain and the starting sensitivity of 84 dB/W (W, not 2.83VRMS; remember, these are 4 ohm drivers) the net total system sensitivity calculated out to 97.98 dB.
Now, looking at the intrinsic frequency response, as well as the low Xmax, I don't personally like the idea of EQ'ing out the bottom end... but crossing these at 100 Hz to an LF Line source (which only need be one LF/sub at the floor, and one at the ceiling), things should be pretty hunky dory using a 12 dB electrical high pass and a 4th order low pass. I can imagine all kinds of configurations that might work well for that, such as those Wavecor woofers, or the 10" RS265, combined with the SS W26/00-0 PR.
now, OF COURSE, the top end is not going to sound like a ribbon tweeter or Beryllium dome top end... but I bet there will be some things the system does overall in a very interesting manner. Interesting enough to try out and if it works dedicate these to GF's front HT mains? I think so...
So, for analysis purposes, what we'd be interested in is, with 4 or 5 wired in series, with a 2.83VRMS drive (4V Pk, 8V Pk-Pk), what does the distortion look like? Because that's about what we'll see at nearly 98 dB output from the finished array. So, that copper cap and other things may be pretty important here.
I'll build a 4 driver test box and see how this looks.
BTW, as usual, I'm thinking that if I eliminate the LF EQ network, then everything else (BSC, HF EQ) may likely be accomplished passively. Possibly. Who knows...
Here I'm going to discuss and present ideas for creating a basic clone of the IDS-25, with a few twists, to use for GF's HT front mains.
First, when considering clones of the IDS-25 system, it's a good idea to be familiar with the original! This is the main page, and much more info can be found from other linked pages:
Russell either had a custom driver built, or was very careful in selecting the driver which he uses. It's not a simple challenge, as one is looking for wide frequency extension, low distortion, and freedom from any high Q break up modes in the top end. I like his approach for the equalizer, but then, like Russel, I'm kind of old school myself, and would do it pretty much the same say - including balanced inputs and outputs available, low noise, low distortion op amps, film caps, etc. :T
Most of the IDS clones I've read about, including Javier's, are somewhat flawed due to their choice of driver, usually made on the basis of cutting cost.
BTW, this Vifa TG9FD-10-04 is purported to be the driver used in the IDS-25. Verified on several sites.
It does use a copper cap to limit impedance rise and upper end distortion, and the cone resonances are well damped.
With the shown driver Fs, they will need some significant LF EQ to perform below 100 Hz. BUT, the sensitivity gain should be high; not really all that much power. Xmax is rated at 2.6mm- not very high.
Still, I'm tempted as a giggle to build some new mains for my GF's family room HT with these, see how they sound. Its a fair sized room, about 18' by 30'.
It's certainly worth running some numbers and modeling. But I would recommend using these like the company below, with a some extra LF reinforcement. I like the physical design because it appears well optimized for achieving good Sd relative to the driver area, and of course, you can pack these together. Front panel design and routing will be an issue- might have to go to phenolic panels, maybe even aluminum.
Interesting... let's see, 50 at $19 each is still pretty close to $1K. Still not an impulse purchase.
Good first step would be to buy a few and see how the distortion measures at low drive levels, and how that would scale with an array to 90 dB level baseline.
*****************************
Geez, another distraction from current projects. Just ordered 4 for testing.
I ran the numbers, and using a configuration of 25 on each side, with five sets of drivers wired in series and then paralleled (a 5 x 5 matrix) with the net efficiency gain and the starting sensitivity of 84 dB/W (W, not 2.83VRMS; remember, these are 4 ohm drivers) the net total system sensitivity calculated out to 97.98 dB.
Now, looking at the intrinsic frequency response, as well as the low Xmax, I don't personally like the idea of EQ'ing out the bottom end... but crossing these at 100 Hz to an LF Line source (which only need be one LF/sub at the floor, and one at the ceiling), things should be pretty hunky dory using a 12 dB electrical high pass and a 4th order low pass. I can imagine all kinds of configurations that might work well for that, such as those Wavecor woofers, or the 10" RS265, combined with the SS W26/00-0 PR.
now, OF COURSE, the top end is not going to sound like a ribbon tweeter or Beryllium dome top end... but I bet there will be some things the system does overall in a very interesting manner. Interesting enough to try out and if it works dedicate these to GF's front HT mains? I think so...
So, for analysis purposes, what we'd be interested in is, with 4 or 5 wired in series, with a 2.83VRMS drive (4V Pk, 8V Pk-Pk), what does the distortion look like? Because that's about what we'll see at nearly 98 dB output from the finished array. So, that copper cap and other things may be pretty important here.
I'll build a 4 driver test box and see how this looks.
BTW, as usual, I'm thinking that if I eliminate the LF EQ network, then everything else (BSC, HF EQ) may likely be accomplished passively. Possibly. Who knows...
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