Not only possible, but easy, obvious and exactly what I'm going to do. The W22 has proven itself exemplary from 100 Hz. to 1400 Hz. . . . clearly dropping the upper crossover to 1000 Hz. or below is not going to compromise its performance. The choice of upper mids is wide open . . . one could use the Scan that John uses, or the Seas "SL", or the Tang Band W4-1337 (certainly the first choice if price matters) or any of a raft of other potentially "interesting" 4" drivers. The demands on the tweeter are so slight that almost anything would do.
The real question is whether to duplicate SL's innovative baffle design (almost an "ah ha" moment at first look). Clearly his intent was to address the vertical polar deficiencies of more "trad" designs . . . whether the shape is as acoustically effective as it is visually striking is not so clear. The close driver spacing has obvious advantage . . . putting the rear tweeter at the top not so much . . . it could go anywhere, reducing the overall height (and visual impact).
But the W22 . . . yes . . . automated active crossover design has made driver selection an almost trivial "plug-and-play" exercise (and it's a great driver) . . .
Seas L16RN-SL? This shares much in common with W22, and its use much above 1kHz is to be avoided. Nasty metal cone break up.
Regards,
Andrew
No, the SEAS MU10RB-SL . . . the upper-midrange in the LX521. Thought that would be obvious to anyone following a 4-way dipole design thread . . . (and the L16 is obviously not a 4" driver).
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You could use any drivers you like and design your own system. I've already been asked if the speaker could be adapted to the SS 8554. Since I have them on hand I indicated I would be glad to make the adaptation. I looked at a number of upper midrange drivers when I designed the original Note. Most did not fair too well. The TangBang were not so good. Plus, most of the crop of these smaller drivers are in the 85dB/2.83 V range, or lower. The SSD 10F is around 90. That is a big plus when it comes to blending it with the lower mid.
If you wanted to send me the W22s I would be willing to do a one off for you. Would take some time. However, I don't think the midrange will be as good. The SSD mids (upper and lower) use the same cone material and that affects how they blend. I'm not a fan of metal cones.
FYI here is a plot of the response of the SS and XXLS woofer based on near field measurements corrected to far field dipole response. I really can see the need for the XXLS since with the 30 Hz B4 cut off I have yet to be limited by max SPL listening, for example, to Telarc recordings of the Rite of Spring or the Firebird.
An externally hosted image should be here but it was not working when we last tested it.
A "big plus"? What difference does sensitivity make when you're designing with an active crossover?
If you are using a digital crossover it is useful to have drivers with comparable sensitivity, or use analog level matching stages, otherwise you have to do the level matching in digital and possibly lose a bit or two of resolution for the driver that exhibits the most sensitivity - usually the mids and hf, which is precisely where you want more resolution, not less.
It is for this reason that DEQX implements a selectable gain analog output, using jumpers, so that e.g. with a 94dB sens. mid array, if you have a woofer section that clocks in at 84dB, one can then add +10dB gain to the woofer. Otherwise, you have to digitally "cut" 10dB from the mids and highs, and in doing that you lose almost 2 bits of resolution.
Some here will undoubtedly ask: Is it audible? Well, I have a DEQX, I've done the comparisons, and for me the answer is a resounding YES. There's a reason DEQX added the extra gain flexibility, and it shows in the sonics. Hardware-wise it's a very well thought out product.
It's not exactly difficult to "normalize" all drivers to the same sensitivity by setting amplifier gain, but even if one doesn't the miniDSP is a 24 bit device, so you're not going to lose any usefull resolution with a bit or two of digital gain adjustment.
Note surprisingly you took my comments out of context. Never the less, as has been pointed out there are good reasons to use drivers with close sensitivity ratings in passive as well as active systems, digital or analog.
But, what I said was,
Recall that in the original Note the complete panel was passive.
..and that started with:
..in other words you stripped it of it's context by removing the "opening" portion of the opening quote (that started the post-reply).
Ideally John should have moved the portion you objected to - to it's own paragraph for greater clarity, but the fact is that the entire post has multiple topics "running throughout". Formatting and spelling isn't high on John's list for forum communication - but then again, it is just forum communication. Most people are glad just to have the information conveyed - even if sometimes it requires a bit of "ferreting-out".
OK to throw away bits? Hmm... that doesn't correlate well with my experience using the DEQX.
The DEQX is also 24 bit, clocks at higher frequencies and is audibly much more transparent, with much higher resolution than the mini-DSP (I've compared them, also vs modded Behringer DEQ and DCX, mini-DSP came in 3rd place IMO, there was a clear difference)
So I'll concede that on the Mini-DSP the difference might be less audible, but since it is so easy to level match at the amp, that is still the best path to pursue.
It's too easy and tempting to trivialize these "minor" differences, but IME when we pay attention to them, the overall quality does indeed benefit.
Yes, I'm well aware that there is a whole brigade of folks on this forum who claim the differences are inaudible in DBT, but I'm not willing to spend time and effort on that subject. If you have ears to hear, then listen.
Bottom line is when a theoretically better solution also turns out to provide better performance (at least to some ears) then it may be the wise thing to not overlook it. And when it comes at no real cost... well... just do it.
This can work really well. But there are exceptions: in some cases, you need extra gain.
For example, with a very high efficiency full-range driver you may be running at close to 97dB or so. With a small SET amp you can get glorious mid-range.
Now, let's decide to use that with a a small volume iso-baric sub. Some of these designs are in the 80dB sensitivity range.
When you pad down the mid/hf section by 17 dB to match the woofer section, you throw away a whole lot of input sensitivity on the amp, and will likely need a pre-amp with sufficient voltage gain to drive this combo properly.
If you like to drive things directly from a CD player or most DACs, on some material that is recorded at low volume, you're just not going to have enough drive to get it sufficiently loud. Thus the need for an additional pre-amp or buffer or transformer section to get back the missing gain.
And, yes, definitely, watch the impedance matching!
Yes, so I've heard. As I said, I'm not prepared to argue the DBT issue, so I'd be pleased if we could give it a rest.
All might be true, but the DEQX and the DCX only give you 3 paired channels out. The miniDSP is 2 in, 8 out which is what is needed. Additional the point of the Note II is maximizing the quality while minimizing cost. You will have a very difficult time finding a speaker that performs as well as the Note II at the same price point of around $1200 + lumber for the enclosure + amps.
But if you don't like the miniDSP choose the dsp crossover of your choice that allows for 4 pairs of outputs and I'll be glad to supply the details of the transfer functions so you can program it.
An excellent point and well worth underlining it in caps.
The QPR for the Note II has go to be off the charts.
In case it seemed like I'm dissing the MiniDSP, that was NOT the intent, so please forgive me. It's actually a very good sounding unit, and yes I think the DEQX sounds better but at a huge leap in price, especially for 4 channels where you'd have to cascade a pair of them.
John, I'd love for you to have a chance to hear what I've done with a Dayton PS220 on a bass-augmented OB. I called it the TimePulse Lambda, have a look at my website. If it's OT or inappropriate for you to respond in this thread just PM me.