Hornresp

Sorry if this has been explained before. does anyone have advice to convert a flared bass reflex using Vrc, Lrc, Ap, and Lpt to horn segments? I can't find anything anywhere else and I can't figure it out with Sohos tutorial he provided I tried a few times a few years ago. Ap/Lpt is two 78" long, 6" I.D. pipes, Vrc is 61.7
 
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Sorry if this has been explained before. does anyone have advice to convert a flared bass reflex using Vrc, Lrc, Ap, and Lpt to horn segments? I can't find anything anywhere else and I can't figure it out with Sohos tutorial he provided I tried a few times a few years ago. Ap/Lpt is two 78" long, 6" I.D. pipes, Vrc is 61.7

Use the "compound horn" option, describe the front of the box using S5-S5, and the rear of the box and the vent using Vtc and S1, S2, S3 and S4.
 
I do it by using Vtc and Atc to describe the box and then use segments to define the flared port. It's simple, quick and easy.

Just to be clear though, you can't sim a flared port at all using Vrc, Lrc, Ap and Lpt. All you can do with that is a simple ported box with a straight (unflared) port. I'm not sure what Soho's tutorial said or even which tutorial you were looking at but it isn't possible. You have to use segments to define a flared port, that's all there is to that.
 
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Both of these are simulated using Vtc and Atc for the box part and segments for the flares.

26LUMHr.png
 
The velocity can currently only be checked at the port ends which is nice to show if velocity issues are going to be a problem at the ends. But you cannot currently check velocity in the narrow part of the port, which is where core velocity issues happen (see Flare It, it will tell you acceptable velocity for both).

Hopefully within the next few weeks or so Hornresp will be able to simulate the core velocity but until then you can use Akabak for that if you need to.
 
Hopefully within the next few weeks or so Hornresp will be able to simulate the core velocity

Hi just a guy,

Just letting you know that the core velocity feature has now been coded (see attachments). It works well, and will be in the next release, along with some other changes that I think you might like :).

Kind regards,

David
 

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Why is the Acoustical power curve different when done through Maximum SPL feature.

Hi dipolar,

For the standard power response, the input voltage is effectively constant (the very small non-zero Rg value you are using has virtually no effect on the results). Although the input voltage is constant, the input power varies across the frequency range due to changes in the frequency-dependent electrical impedance.

The Maximum SPL response shows the maximum level that can be achieved without exceeding either Pmax or Xmax. In this case it is the input voltage that varies.

Using your example to illustrate the difference:

Attachment 1 shows the sample result at 60 Hz for the standard response. The input power is 1.7965 watts for a constant input voltage of 2.83 volts.

Attachment 2 shows the sample result at 60 Hz for the Maximum SPL response. The input power is 1.0000 watt (your specified Pmax value of 1 watt is the limiting factor in this case) and the input voltage required to generate the input power of 1 watt is 2.1114 volts.

Kind regards,

David
 

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Hi dipolar,



The Maximum SPL response shows the maximum level that can be achieved without exceeding either Pmax or Xmax. In this case it is the input voltage that varies.


Attachment 1 shows the sample result at 60 Hz for the standard response. The input power is 1.7965 watts for a constant input voltage of 2.83 volts.

Attachment 2 shows the sample result at 60 Hz for the Maximum SPL response. The input power is 1.0000 watt (your specified Pmax value of 1 watt is the limiting factor in this case) and the input voltage required to generate the input power of 1 watt is 2.1114 volts.

Kind regards,

David

Thank you Dave .

One more doubt, Does this mean the Box would sound very Boomy at 36hz and 95 hz when measured or it is just what amplifier will see .

Which means, is it a right Enclosure to begin with,it is my first attempt.

Kind regards.
 

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Thank you Dave .

One more doubt, Does this mean the Box would sound very Boomy at 36hz and 95 hz when measured or it is just what amplifier will see .

Which means, is it a right Enclosure to begin with,it is my first attempt.

Kind regards.

Continued from yesterday,

I could not figure out how to remove those peaks in final simulation incase that is what my final measurements would be in front of horn mouth
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Loudspeaker wizard Acoustical Power Curve looks fine but when the Max Spl feature is used the Peaks appears.

Using your example to illustrate the difference:

Attachment 1 shows the sample result at 60 Hz for the standard response. The input power is 1.7965 watts for a constant input voltage of 2.83 volts.

Attachment 2 shows the sample result at 60 Hz for the Maximum SPL response. The input power is 1.0000 watt (your specified Pmax value of 1 watt is the limiting factor in this case) and the input voltage required to generate the input power of 1 watt is 2.1114 volts.

My apologies,
I think I didn't quite well understand how and why it is related to almost 14db Peaks in frequency response (or 3db down at 55hz ) contrary to what is shown by Loudspeaker wizard acoustical power curve.
Kind Regards.
 

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Loudspeaker wizard Acoustical Power Curve looks fine but when the Max Spl feature is used the Peaks appears.

That's because the two charts have different inputs, as previously explained.

For the purpose of your analysis I suggest that you just ignore the Maximum SPL chart, and concentrate on optimising the standard power response results.
 
I could not figure out how to remove those peaks in final simulation incase that is what my final measurements would be in front of horn mouth.

The peaks in the MaxSPL curve will not appear in your measurements in front of the horn.

Loudspeaker wizard Acoustical Power Curve looks fine but when the Max Spl feature is used the Peaks appears.

That is because the MaxSPL curve is not your frequency response. The curve is useful for examining how loud the speaker can play at various frequencies, but not for examining the the frequency response.

If you want to see the frequency response for a nominal 1W input, and your speaker is 8 ohms nominal impedance, you set Eg to 2.83V and look at the power response.

But: since the electrical impedance of the speaker will vary, your actual power input will vary. This is as it should be. You should not expect the amplifier to deliver 1W to the speaker regardless of speaker impedance, amplifiers that do this are not available commercially.

In addition, the efficiency of the speaker will vary with frequency. That means that for a constant power input, you will get much higher output at the frequencies where the speaker is most efficient. This is the cause of the peaks you see at ~30 and ~90Hz.

But luckily you will not see that. Most amplifiers deliver a constant voltage output. In this case, power input will be reduced at these frequencies, and you will get the much flatter frequency response of the "Acoustical Power" chart and the Loudspeaker Wizard.

To sum up, the MaxSPL curve is the maximum capability of the speaker, not the frequency response. And the power you enter in the Max SPL dialog should be the power rating of your driver, not the nominal input power.

I hope this helped in making things a little clearer. But until you understand what the MaxSPL curve actually shows, just ignore it, as David said. It is not your frequency response, it is not what you hear, and it is not what you measure. It is only of interest if you need to know the limits of how loud your speaker can play.