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Introducing Denotiva DIY speakers!
OP
- Thread Starter
- #102
Might be wondering where is that spin Rick promised? Well I got the passive crossover built and had to tweak it a bit. All around it looked pretty good and then I noticed the scale on the impedance chart. After I adjusted it, found my tweeter crossover had a substantial 2 ohm dip. I had also allowed the parts count to creep up and adding cost. So, have gone to an earlier design and am building a new more amp-friendly crossover.
OP
- Thread Starter
- #103
Since I had bothered to build the crossover, used it to confirm my sim even with the impedance dip. The sim was a good match but found another issue that will likely force out the Dayton ND25FW. Even at my fairly high (3 kHz) crossover point, it has a distortion peak around 1.3 kHz. I went back and looked at Amir's C-Note measurements (and my driver measurements) and confirmed it. I apparently overlooked it on a $100/pair speaker, but for Denotiva, am not willing to ignore. My planned crossover redesign might improve this slightly but unlikely to be better than the C-Note.
As I had it on the stand, gave it a quick listen and thought it sounds pretty good. It has a sharp distortion peak. May not be all that audible (as Amir did not complain either) but not up to my target and there are plenty of other tweeters to consider.
EDIT: turned out was mistaken about the tweeter, please see subsequent posts.
As I had it on the stand, gave it a quick listen and thought it sounds pretty good. It has a sharp distortion peak. May not be all that audible (as Amir did not complain either) but not up to my target and there are plenty of other tweeters to consider.
EDIT: turned out was mistaken about the tweeter, please see subsequent posts.
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terryforsythe
Major Contributor
The 1.3 kHz peak looks like it is helping to fill in a dip in the woofer's response. It doesn't look to be negatively affecting the directivity index too much. The question is whether it is generating high THD. If not, I think it looks quite nice. Good job on the crossover design!
I can't say I heard any distortion related to the nd25fw in my builds even at very high spl. Is the little bump in my non-spl calibrated measurement what you see? The yellow line rises a bit in the mid range. This was super duper loud, have to wear protection to be in the room sort of loud.
Curious to see what tweeters you try, but I will say if one wishes to hear what a crazy value the ND25fw can present, one needs to hear it on a baffle similar to what Kii does, large 2-3" radius round overs that begin near where the WG ends and a 5" woofer (I just used the cnote woofer). I'm not sure if this fits the design goals of the Denotiva, or how one even creates such round overs, but that driver combo shocks me with how good it sounds. I hope to come up with something one day that can sit in a living room but nothing I've done has come close to sounding this good, and it blows me away that it's a (currently) $14 tweeter. But I do think a 6" and up woofer is too large for it. This is just some simple 2nd order active filters at around 3k with cnote drivers.
Curious to see what tweeters you try, but I will say if one wishes to hear what a crazy value the ND25fw can present, one needs to hear it on a baffle similar to what Kii does, large 2-3" radius round overs that begin near where the WG ends and a 5" woofer (I just used the cnote woofer). I'm not sure if this fits the design goals of the Denotiva, or how one even creates such round overs, but that driver combo shocks me with how good it sounds. I hope to come up with something one day that can sit in a living room but nothing I've done has come close to sounding this good, and it blows me away that it's a (currently) $14 tweeter. But I do think a 6" and up woofer is too large for it. This is just some simple 2nd order active filters at around 3k with cnote drivers.
OP
- Thread Starter
- #107
Directivity and Power Response look really good. Shame about that distortion. Is it really audible at -18db? Seems like just too low to overcome the woofer contribution.
Thanks! For the price, the tweeter is still a good value. The woofer is too at OEM pricing. Audibility may be moot and for the C-Note looks like it was buried in the woofer resonance. My distortion measurements are not ideal and so will take another pass under more controlled conditions. Do not like that it occurs in key midrange but might be a reasonable compromise for some.
I realized that the using the DXT would very closely resemble the DXT-Mon and want something more unique. There is a Wavecor tweeter that seems a better match and so will likely try it. Then Denotiva perhaps becomes Wavenotiva?
Roland68
Major Contributor
Speaking of DXT-Mon, have you seen these tweeter tests, some with adapted waveguides?Thanks! For the price, the tweeter is still a good value. The woofer is too at OEM pricing. Audibility may be moot and for the C-Note looks like it was buried in the woofer resonance. My distortion measurements are not ideal and so will take another pass under more controlled conditions. Do not like that it occurs in key midrange but might be a reasonable compromise for some.
I realized that the using the DXT would very closely resemble the DXT-Mon and want something more unique. There is a Wavecor tweeter that seems a better match and so will likely try it. Then Denotiva perhaps becomes Wavenotiva?
https://heissmann-acoustics.de/treibertests/
OP
- Thread Starter
- #109
Thanks, but while interesting, this effort is focused on off-the-shelf drivers.
As with Directiva, want to make this easy to build for even the layman. DIY hobbyists can always take it another direction with mods, but is not my focus here.
Roland68
Major Contributor
You misunderstood me, I was talking about all the normal tweeter tests, as there are also cheaper ones.
The thing about the adapted waveguides was just an additional hint.
OP
- Thread Starter
- #111
Sorry, am a bit distracted currently...
After earlier comments and @Ktacos shared measures, did some troubleshooting and the source of the distortion is on the bass side. I had another crossover that allowed me to more readily isolate the drivers. Am still trying to determine root cause.
OP
- Thread Starter
- #112
As the issue follows the woofer, am tempted to finger point the woofer. The distortion is closer to 1 kHz and happens with a different crossover. It could be related to mounting too as am only using screws to mount it. Recall the Dayton ES180 exhibited some distortion around 1k and hificompass measures of a comparable Wavecor woofer indicates resonances in that area too. I misled myself earlier as the tweeter does have high distortion around 1 kHz but was a raw driver measure and that is around the fS of the ND25FW.
Always compromises with drivers. Will continue to investigate and seek mitigations.
Always compromises with drivers. Will continue to investigate and seek mitigations.
Inertiaman
Active Member
- Joined
- Sep 25, 2023
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- 624
With the WF182 and passive radiator involved, adding the DXT would line up with Heissmann's DXT-Mon-182 more so than the original DXT-Mon.
Personally I wouldn't object to a
FWIW, Heissmann claims an F3 of ~ 36Hz in an 18L cabinet w/ the affordable Dayton DSA-215PR.
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OP
- Thread Starter
- #114
Maybe after Directiva r2, can try since I have the drivers is primarily my time.
Why not let that lay down..?Heissman has been generous with the DIY community, with nice stuff for free on his site, duplicating one of is designs, that he developed for (little) profit doesn't seem ethical to me.
a4eaudio
Active Member
- Joined
- May 7, 2024
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Using the same drivers but designing a different crossover is not duplicating someone's design nor unethical in any way. Buying his design and then publishing his exact crossover would be unethical.
Inertiaman
Active Member
- Joined
- Sep 25, 2023
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I tend to agree with e4audio on this one.
No one has an ethical monopoly on driver combinations. Heissmann himself sells a modest re-design of Mark K's original ER18+DXT speaker, with essentially identical cabinet volume but with a different crossover and chamfered baffle. So using his DXT182 as an inspiration for a DIY speaker with different x-over and potentially different woofer model, cabinet volume, etc is hardly unethical.
FWIW, I've personally purchased designs from Heissmann. I'm not averse to spending $$ for a reasonably simulated/measured design.
Original post edited to be more clear about my suggestion, which was essentially just noting that the DXT + 182 + PR is a potentially potent combo.
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OP
- Thread Starter
- #118
Initially, was of the same line of thought. However, my design would not be identical and more suited for the North American market. My experience on Directiva has shown that it can be difficult/expensive to acquire the exact same parts globally.
Dave Bullet
Member
- Joined
- Oct 30, 2022
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- 117
You probably know the ND25FW resonance is coming into the response here. Some impedance compensation may benefit greatly to reduce the likely "honkiness" being generated by the tweeter.
