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  • Lowest distortion drivers

    Contemplating one more.
    My current system is the Seas 7 inch reed paper with 27TBC/G . Both pretty good. But I know there are lower distortion with even smoother response drivers making them easier to use.
    I have a pair of HDS tweeters, never used as they have to be crossed so high. The Santori tweeter looks good as does the Transducer Technology. I have found several measures of the above, but never in the same context to make a fair comparison. Any experience? Am I missing one? CSS? No horns or waveguides please.

    Then to match a mid-woofer. The new SB ceramic looks good. Maybe Santori. CSS? Revelators are low distortion, but response is very hard to integrate. Purify is a bit expensive. I was thinking a pair of 5's as maybe they could cross higher avoiding tweeter distortion. Maybe D'Apolitto alignment as my room in not the best and bringing down the beam woudl be good. I run a god sub, so I don't need to get below 70 or even 80. I can just get new modules for mu crossover. Might even consider a 3 way, 7-4-1 if the midrange is good enough. Never found what looks like a really low distortion mid. One would think it would be the easiest.

  • #2
    If you want low distortion then opt for appropriately sized drivers in a 3 way. Even with decent standard range drivers rather than prestige range drivers it can be expected to outperform a 2 way using prestige range drivers. Note that 7" is more of a midwoofer size for a 2 way or a lower mid for a 4 way with a 3 way benefiting significantly from a larger driver. The distortion we hear tends to be more closely correlated with intermodulation distortion rather than the THD often shown and this grows not only with driver deflection but also the width of the driver passband.

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    • #3
      My floor-standing Brioso 2-way speaker uses an SS 7" Revelator mated to a Transducer Labs tweeter. Dan Neubecker did the crossover design and commented it took him only 3 iterations to get it done, uses only 6 (or 7) components, was very easy to design, plus sounded very smooth, which certainly implies easy integration of the two drivers. Oh, the judges and fellow DIYers at the 2017 MWAF voted it into 1st place in the over-$200 category. I'd be happy to send you my write-up. If you're interested, send me a Private Message with your email address. The only drawback you might find is that it's one of those out-dated TL designs.
      Paul
      Click image for larger version

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      Originally posted by tvrgeek View Post
      Contemplating one more.
      My current system is the Seas 7 inch reed paper with 27TBC/G . Both pretty good. But I know there are lower distortion with even smoother response drivers making them easier to use.
      I have a pair of HDS tweeters, never used as they have to be crossed so high. The Santori tweeter looks good as does the Transducer Technology. I have found several measures of the above, but never in the same context to make a fair comparison. Any experience? Am I missing one? CSS? No horns or waveguides please.

      Then to match a mid-woofer. The new SB ceramic looks good. Maybe Santori. CSS? Revelators are low distortion, but response is very hard to integrate. Purify is a bit expensive. I was thinking a pair of 5's as maybe they could cross higher avoiding tweeter distortion. Maybe D'Apolitto alignment as my room in not the best and bringing down the beam woudl be good. I run a god sub, so I don't need to get below 70 or even 80. I can just get new modules for mu crossover. Might even consider a 3 way, 7-4-1 if the midrange is good enough. Never found what looks like a really low distortion mid. One would think it would be the easiest.

      Comment


      • #4
        Anyone use the Morel EM1308 Elite 2" Dome Midrange? On paper, it would seem to bridge from a 7 to a 1 quite well. Satori on the bottom and either my existing HDS or the Trans lab up top. Using the HDS will save me a few quid.

        Doing some measurements, and thinking back on how the different amplifier compensation VAS loading vs Miller, effects ultrasonic harmonics and how tweeters actually produce sub harmonics, a mid starts to sound more viable. Quite disappointing how high a lot of mid-bass exceed X-max before reaching "crescendo" levels. Makes that Satori start to look very good.

        Then there are all the "full range". Some cover the mids pretty well, Fostex, Fountek, Mark etc. I played with a Zaph and still run FE85's on my desk, but don't call either low distortion.

        PM sent, yes please

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        • #5
          I've used the MDM55 (which I acknowledge is a generation older) a couple of times and while it sounds good, it's kind of a hassle to use. It doesn't reach all that low (800Hz is as far as I'd push it and it's happier to my ears closer to 1k, but per comments I've read, the EM1308 can go a bit lower), and due to CTC spacing issues, you don't really want to go much higher than 4K, and that's if you start truncating faceplates. With it covering such a small band, the impedance is hard to keep up unless you pad it down a fair amount (at least in my experience).

          You'll probably have to cross the 1308 a fair bit lower than the MDM55 because of the larger faceplate. I looked at it for my last 3 way project, and it didn't make sense from a CTC spacing issue - you'd have to cut way into the semi-waveguide thing to control power response and dispersion at the XO point - a quick back of the envelope calculation looks like you'd have to be in the 2.8-2.9k range to control it if you don't cut the faceplate.

          If you are considering a 3 way, you may want to look at some of the 3/4" domes (cough... Hiquphon ...cough) or top end ribbons - like the RAAL (haven't tried but would love to). I'm not sure the 1" being capable of playing lower just so you can filter it out is a worthwhile tradeoff over improved off-axis. It's not a compromise I normally make.

          The next 3 way I build will probably have an SS, Excel, or Satori +-4" mid of some sort or the little BMR Dennis Murphy uses. I've used its big brother (which looking at measurements/numbers, is not as nice) in a little 2-way, and the dispersion of that thing is incredible and it sounds very good. I really want to like the purii 4", but it doesn't seem to make sense as a mid since it can reach so low with authority and makes trade offs to do so.

          I don't know if Rick Craig comes around here much, but back in the old Maidsound board days, he was a dome mid guru. It could be worth reaching out to him if you want more experience on the morel dome mids.

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          • #6
            There are several 3 inch Tang Band's that look interesting. Darn fancy aluminum face plates, harder to trim than the plastic ones. But yea, the 2 inch domes are really narrow band. I remember several years ago I went looking for the killer mid and did not find it. Kind of thinking the smaller Satori mid-woof as it looks like it may get up to where tweeters are happy and the simulation says it will get low enough without running out of displacement. I do see the point, the higher the crossover, the more critical the center to center distance. Darn physics. Makes me wonder if a better approach is the new Peerless 1 1/4 carbo-something fancy name for ceramic tweeter and go for the lower crossover in a 2-way. Morel makes that plate with the 2 inch and a 1 inch built in together closer than you could otherwise. Clever idea, but I played with one Morell and was not very impressed.

            Kind of funny. Look at the $100,000 speakers and they tend to have a lot of drivers far apart, often in separate boxes. And I go through the trouble of cutting notches in my tweeters. Below are the HT mains I just converted into in-wall. Nothing special. Dayton RS150's and Seas. T27 softs. Crossover was a bear to get the Dayton breakup down far enough. Seas drooping top end was critical as Anthem ARC does not eq above 3K. XT-25's I used before were too flat even though I am way off axis. I may be on a wild goose chase. Everything is pointing back to the good old days, floor standing 10 inch 3-ways. Pre sub. Alas, my living room does not have the space for that. A 6-3-1 is going to be hard enough to make short enough as it is. Those TB's are so ugly, going to have to do grill cloths. OK, brain is hurting.
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            • #7
              Spent the day measuring distortion on everything on hand. Tried to use RIghtMark but I could not get a -1 reference and it not overload in other tests, so had to drop back to TrueRTA and a dozen selected frequencies, record by hand. Measuring @ 2.86V, regardless of impedance, just to get a relative comparison.
              As expected the Seas t27TBFC was a good bit worst than the T27TBFC/G but I knew that from listening. HDS, frequently suggested as so great, really was a toss up with the XT-25G. Cheaper stuff measured worse of course. In all cases, second harmonic was 5 to 10 dB higher than third. In all cases, higher order were lo enough to ignore. I did not drive the tweeters hard enough to see sub-harmonics.
              Confirmed the RS150 is darn decent not just for the price. RS125 is not. Bummer. 7 inch Seas reed about the same distortion wise, but of course other advantages. I think there are far better mid-bass, or at least the published specs say so. Tweeters are harder as all I get is things like "Satori tweeter is like the SB but cleaner" Not exactly objective information and I don't have the greenbacks to buy them all and test.

              As there is no standard for measuring distortion, any suggestions are welcome. The numbers I got were significantly higher than I expected, running from .8 to 6%. Most in the middle 2% to middle 3% for tweeters, a bit less on the woofers. I think for fair comparisons, one woudl need to pick a frequency, say 500 for woofer and 3K for tweeter, to set an SPL around 85, then measure with that in a sweep.

              Looking for very good midranges. 1000 to 3000 or so. Some look good but efficiency is very low so not sure how one woudl integrate them with woofers @ 88 dB, mids @ 83, and of course we pad the tweeters as they are in the 90's. The SB 2 inch dome looks like one to at least test.

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              • #8
                Originally posted by tvrgeek View Post
                Spent the day measuring distortion on everything on hand. Tried to use RIghtMark but I could not get a -1 reference and it not overload in other tests, so had to drop back to TrueRTA and a dozen selected frequencies, record by hand. Measuring @ 2.86V, regardless of impedance, just to get a relative comparison.
                As expected the Seas t27TBFC was a good bit worst than the T27TBFC/G but I knew that from listening. HDS, frequently suggested as so great, really was a toss up with the XT-25G. Cheaper stuff measured worse of course. In all cases, second harmonic was 5 to 10 dB higher than third. In all cases, higher order were lo enough to ignore. I did not drive the tweeters hard enough to see sub-harmonics.
                Confirmed the RS150 is darn decent not just for the price. RS125 is not. Bummer. 7 inch Seas reed about the same distortion wise, but of course other advantages. I think there are far better mid-bass, or at least the published specs say so. Tweeters are harder as all I get is things like "Satori tweeter is like the SB but cleaner" Not exactly objective information and I don't have the greenbacks to buy them all and test.

                As there is no standard for measuring distortion, any suggestions are welcome. The numbers I got were significantly higher than I expected, running from .8 to 6%. Most in the middle 2% to middle 3% for tweeters, a bit less on the woofers. I think for fair comparisons, one woudl need to pick a frequency, say 500 for woofer and 3K for tweeter, to set an SPL around 85, then measure with that in a sweep.

                Looking for very good midranges. 1000 to 3000 or so. Some look good but efficiency is very low so not sure how one woudl integrate them with woofers @ 88 dB, mids @ 83, and of course we pad the tweeters as they are in the 90's. The SB 2 inch dome looks like one to at least test.
                lol thanks for the chuckle.
                Don't listen to me - I have not sold any $150,000 speakers.

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                • #9
                  Reading here, I can see what I might expect with newest SOA. Tells me my measurements may not be very far off.
                  http://www.troelsgravesen.dk/SBA-761.htm Impressive design BTW.

                  Under 2% mostly. Not under 1.

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                  • #10
                    I must admit, your priorities are interesting to me. Driver distortion is obviously important to you, yet your source is an AVR and you are considering installing speakers in your door..

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                    • #11
                      tvr, knowing that you're (kinda) new here, have you ever visited zaphaudio.com ?

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                      • #12
                        Also good sites for driver measurements including HD:

                        hificompass.com
                        http://feleppa.com.au/speakersaudio.html

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                        • #13
                          Been to Zaph. Many times. Even had some of his spec drivers. OK for the price I guess. A little better with some mods I did. My current living room mains were inspired by his SR-71. His testing is very good, but also a decade old. Many newer drivers are out there. The Transducer Labs, the new Peerless, and of course Satori had not been introduced yet.

                          Maybe new on this forum, but I have been building speakers for 45 years. Never had time for forums while I was working.

                          Dayamo,
                          Yea, for my HT, I run an Anthem 310 AVR. Distortion in the .03% range. Sufficient power for the small room. Yes, looking to put the speakers in-door ( or in-wall if you like the term better) as the room has serious limitations. There is no way to do a nice 4 inches of OC board, move big floor standers out 3 feet, set up a chair in the center of the room to go 16 channel DTS whatever garage. It is a 12 x 12 guest room. I am looking to do as best as I can. Yes, I and more so my wife, are very sensitive to distortion. Going back and forth if a 4.1 or a 5.1 works better. Right now, with my current wall plates (Dayton/Seas) hanging from string, the imaging is much better with 4.1, but for music, it is too point-source. The current Seas soft domes run between 3.5 and 6% distortion. Maybe if you wanted to toss 100K this way, I could add on a dedicated HT room and then I could spring for a high end processor and a stack of amps. If I stay 4.1, I might just swap in my old MOSFET on the mains. AVR is 60W, and that is about my amp.

                          Measurements suggest I can keep the RS150's, or a pair of the smaller Wavetek, but a toss up between the SB 29RDAC-C0000-4, SB26ADC-C000-4, or Peerless DA32TX00-08 for the HT tweeters. Pretty close to line of sight, so the off-axis of the ring radiators is not an issue though if I go for them, I might "wedge" them a tad to help with near reflections. The two domes, the off axis is an advantage.


                          FWIW, my living room for serious music is my own Seas based mains, Peerless sub, Parasound amp, Schiit DAC/pre, O-audio plate on the sub sourced from a WMP touch screen. It is equalized totally with levels, crossover adjustments, and slight tweak with a tone control. No DSP needed. I intend to upgrade the speakers too as as good as the Seas alloy domes are, the newer ones are better. It looks as if I can go from mid 3% to under 2. It is also not the best of rooms. My living room in Maryland was much bigger. But I would live in a shack before I had to stay in P.G. county another day.

                          Thinking about new living room speakers, Transducer Labs or Satori tweeters. I have yet to find objective measures though. On paper the OW-1 might look good, but distortion is worse than my Seas. The Satori and Wavetek woofers does look to be a step up from the Seas.

                          All this at once. This is a last big go-through as by it is time for the next upgrade, it will be a table radio for the nursing home. I actually have an old Sony in the shop I am going to tweak. Oh, reboxing my FE85/XT-25 based desktops to fit the desk space better while I am at it.

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                          • #14
                            Originally posted by hex168 View Post
                            Also good sites for driver measurements including HD:

                            hificompass.com
                            http://feleppa.com.au/speakersaudio.html
                            Thanks, I had not found that. I see the Dayton 2 inch mid did test well and th elittle TB drivers might be pretty good mids. I need to look at that VIfa some.

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                            • #15
                              What size midrange? The 8" Dayton PM220 has some very nice midrange sounds. I have several pairs and really like them.

                              Check it out here: https://audioxpress.com/article/test...ymium-8-woofer

                              According to the article, 2nd harmonics look to be mostly under 1% and third harmonics look almost non-existent.

                              There is a PM180 also, it might be even better in the midrange...

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