First trials of active horn speaker

[Argonaut]

but I think the 18 sound horns are very competently designed and I don’t think it’s profile, which is very sophisticated to avoid resonance but I think the material is kind of thin plastic that probably causes it. I might damp them and see again.

I suspect that you are on the right track there , the results should prove interesting.

 

[bonzo75]

There was some nasality with the 18 sound horns with some vocals that is totally absent with the wood horns. Is it the wood ? The shape? Hard to say but I think the 18 sound horns are very competently designed and I don’t think it’s profile, which is very sophisticated to avoid resonance but I think the material is kind of thin plastic that probably causes it. I might damp them and see again.

Nasality can come from the throat. Both horns are same cut off?

 

[Robh3606]

There was some nasality with the 18 sound horns with some vocals that is totally absent with the wood horns. Is it the wood ? The shape? Hard to say but I think the 18 sound horns are very competently designed and I don’t think it’s profile, which is very sophisticated to avoid resonance but I think the material is kind of thin plastic that probably causes it. I might damp them and see again.

Did you take any measurements?? Could also be differences with your crossover points. You went lower could be a peak in the "woofer" hard to say either way unless you know what the response is for each individual driver.

Rob

 

[Solypsa]

That would have been my guess too. Let us know if you isolate the issue !

 

[Solypsa]

And yes those very small interface differences at the throat can be huge re sonics ....

 

[Solypsa]

Not unlike port matching intake manifolds on a high output engine haha

 

[DasguteOhr]

Super linear, good beam angle 18 sound
Put the horn in a sand filled wood chamber.

 

[Audiohertz2]

Super linear, good beam angle 18 soundView attachment 113316
Put the horn in a sand filled wood chamber.

Hello,

Thanks for posting and I’m trying to understand your graph , it appears to me that this is a very “Beamy” graph , is this a good thing ..?

Would this make the speaker sound hot when on axis ..?


Regards

 

[Audiohertz2]

Nasality can come from the throat. Both horns are same cut off?

What causes them to sound shouty ..?

 

[Robh3606]

Hello,

Thanks for posting and I’m trying to understand your graph , it appears to me that this is a very “Beamy” graph , is this a good thing ..?

Would this make the speaker sound hot when on axis ..?


Regards

That is just a normalized curve of just the horn. You can throw that out an octave above the crossover and lower. I tells you nothing of what the system look like. That's a tight beam depends on how it's integrated in the system. If you have it flat on axis as you move off you will hear the highs drop off. The overall power response may suffer.

Rob

 

[Robh3606]

What causes them to sound shouty ..?

Typically peaks in the response or the horn a bit to loud overall.

Rob

 

[RCanelas]

What causes them to sound shouty ..?

Higher order modes from deficient profiles is the classical reason. Nowadays, in most profiles diffraction from the horn mouth is the typical culprit if no major frequency response issues are present. A slight phase mismatch in the crossover region can also be the reason, but it’s typically more noticed as a nasally reproduction.
Just listing the canonical reasons, nothing pointing this is the case here, don’t see anything jumping out.
Really cool looking project @morricab!

 

[morricab]

Super linear, good beam angle 18 soundView attachment 113316
Put the horn in a sand filled wood chamber.

Yes, haven’t given up on it yet because there is a lot to like in the sound. They said the wooden Tractrix is really a good match with the Beyma driver.

 

[morricab]

Higher order modes from deficient profiles is the classical reason. Nowadays, in most profiles diffraction from the horn mouth is the typical culprit if no major frequency response issues are present. A slight phase mismatch in the crossover region can also be the reason, but it’s typically more noticed as a nasally reproduction.
Just listing the canonical reasons, nothing pointing this is the case here, don’t see anything jumping out.
Really cool looking project @morricab!

The 18 sound horn uses their computer modelled ellipsoidal profile that was designed to eliminate HOMs and be constant directivity. It has a larger sweet spot than the wooden Tractrix. It also doesn’t have diffraction issues…I just think the material and thickness let it down a bit.

 

[morricab]

Hello,

Thanks for posting and I’m trying to understand your graph , it appears to me that this is a very “Beamy” graph , is this a good thing ..?

Would this make the speaker sound hot when on axis ..?


Regards

The constant directivity means that the beam is not narrowing significantly at the higher frequencies. A non CD horn will narrow much more.

 

[morricab]

I still need to go back to try the Iwata horn with Beyma CP350TI driver. At 800hz it might be a bit too low.

 

[bonzo75]

The 18 sound horn uses their computer modelled ellipsoidal profile that was designed to eliminate HOMs and be constant directivity. It has a larger sweet spot than the wooden Tractrix. It also doesn’t have diffraction issues…I just think the material and thickness let it down a bit.

What are the cut offs of both horns

 

[morricab]

What are the cut offs of both horns

All been discussed previously in the thread.

 

[DasguteOhr]

I still need to go back to try the Iwata horn with Beyma CP350TI driver. At 800hz it might be a bit too low.

I took a look at the driver. you use set amp for this speaker? then you need to flatten the impedance spike if you want to use it below 2khz. this is done with the help of a suction circuit .without that could lead to problems discoloration or shouty.

If there is a constant load, e.g. 4 ohms, for which the transformer is intended, the frequency response is linear.
The tube always "sees" the same working resistance.
(e.g. with 300b single-ended )
If the load resistance now increases at a certain frequency (e.g. 2kHz), the tube "sees" a lower load and the output voltage increases.
This increases the volume of the range.
A speaker that has greater impedance fluctuations will not always be linear on a tube amp.

P.S maybe that's the problem and not the horn.

 

[morricab]

I took a look at the driver. you use set amp for this speaker? then you need to flatten the impedance spike if you want to use it below 2khz. this is done with the help of a suction circuit .without that could lead to problems discoloration or shouty.View attachment 113319

If there is a constant load, e.g. 4 ohms, for which the transformer is intended, the frequency response is linear.
The tube always "sees" the same working resistance.
(e.g. with 300b single-ended )
If the load resistance now increases at a certain frequency (e.g. 2kHz), the tube "sees" a lower load and the output voltage increases.
This increases the volume of the range.
A speaker that has greater impedance fluctuations will not always be linear on a tube amp.

P.S maybe that's the problem and not the horn.

This is not the driver on the 18 sound horn. On the 18 sound horn or wooden Tractrix I use the Beyma CP755TI.