Compression drivers in undersized horns

[Pano]

It's never lost.
You just use the driver as low as it's capable to work without audible issues. And contrary to many people's beliefs (for which there's no real evidence), in a home use this can be quite low.

Audible issues come pretty quickly. They are very easy to hear on pure tones or sweeps, but music tends to mask them. Same as for direct radiators.

I don't know about "quite low". Like many people, I've tried to push horns and CDs as low as they can go. I always end up with a higher crossover point than what was hoped for - because it simply sounds better.

 

[mabat]

DonVK, Pano - All you really said is that every device has its limits, which I agree, I didn't say it doesn't.

 

[ErnieM]

In theory, the Bliesma T34 and modern 3" diaphragm compression drivers should have approximately the same maximum output(down low) according to their respective xmax limits.



A 4" compression driver would be +10db(again, in theory) over the above. A little more with the Axi2050 or coaxials from B&C/BMS.



Not a great value over cones in that range.

 

[docali]

DonVK, Pano - All you really said is that every device has its limits, which I agree, I didn't say it doesn't.

Where are these limits in a 7cm long wg?

 

[mabat]

That depends mainly on the device that is attached to such waveguide. You didn't pay much attention, did you
Sorry, but that's not even a meaningful question.

- Or should I ask what is the cut-off?

 

[docali]

And you decide what is a meaningful question in this forum?

Ok, you showed pictures of your HF1440 driver. What is the lowest x-over frequency for this driver attached to your Ce360 or similar optimized for it combined with a high efficiency woofer rated at about 97dB in a 2-way?

 

[mabat]

And you decide what is a meaningful question in this forum?

No, but I can recognize it when I see it. If you claim it was a meaningful question, tell me what the answer is

Ok, you showed pictures of your HF1440 driver. What is the lowest x-over frequency for this driver attached to your Ce360 or similar optimized for it combined with a high efficiency woofer rated at about 97dB in a 2-way?

I don't know, I would have to try, that driver is still completely new to me (and it depends on various things you didn't mention and maybe even consider). Do you know already?

 

[docali]

Really?

I only think that you have an amusing discussion style . But is is good that you are here in this thread as I think the thread title is a best fit to most of your designs.

 

[mabat]

OK, so where are the limits in a 7cm long wg? You still seem to consider that a meaningful question, so what is your answer? Amuse us.

 

[ICG]

You still seem to consider that a meaningful question, so what is your answer? Amuse us.

Why does the one who asks the meaningful question have to have the answer himself? If that would be the case, the question would be either rethorical or it didn't need to be asked. To claim a question is not meaningful because someone doesn't know the answer themselves is equally to show the whole forum a hand gesture with emphasis of a selected digit.

 

[mabat]

Come on, it's not a meaningful question.

This is almost like some Monty Python sketch.

 

[b_force]

How meaningful or meaningless a question is depends on the person who is asking and if he/she is aware of it.
You can never decide how meaningful certain information is to the other person.
Maybe he/she want to know something more on a totally different level.

For the same fact and logic, dumb questions don't exist, unless somebody already knows the answer to his question beforehand maybe.
But than it would be a question that is maybe unnecessary at most.

Instead of calling something not a meaningful question, one could also explain why it wouldn't be meaningful instead. If you don't, you simply don't have the knowledge to explain the question, or you're just simply coming across as being a little arrogant.

There is a big difference between saying how someone can come across and what someone actually is, for the record.
Even more so with different cultures.

 

[mabat]

Waveguide length doesn't set limits on its use. Right?

It's the same as if jealousy should have a color. It simply doesn't have a color. You can ask what color is jealousy but it's not a meaningful question, no matter what words you put in bold.

 

[b_force]

Waveguide length doesn't set limits on its use. Right?

It's the same as if jealousy should have a color. It simply doesn't have a color. You can ask what color is jealousy but it's not a meaningful question, no matter what words you put in bold.

If somebody is not aware about the fact that jealousy doesn't have a color?

Obviously that is an overly simplified example, but the reason for waveguides is a whole less obvious.

Besides, depending on the context, I don't even fully agree with it.
Also not saying that I disagree with it.
I am saying it depends, also what kind of definitions people use.

Anyway, point is, explain to people why it is, instead of saying it's not a meaningful question.
Mostly because that last part is everything except being constructive in any way. And therefor as "useless" as the question itself.
If it is that obvious and simple to you, it is also a piece of cake to explain to people why that is.

 

[ICG]

Waveguide length doesn't set limits on its use. Right?

It does. If it's very shallow, it doesn't have any effect. The question isn't very precise though, it comes down to the angle of it and the mouth size.

It's the same as if jealousy should have a color. It simply doesn't have a color. You can ask what color is jealousy but it's not a meaningful question, no matter what words you put in bold.

That's a completely wrong analogy. Firstly, the color probably has to fit the room design, so it's not irrelevant. Secondly, you can't force someone to not care about the color. If that's relevant to him, you can say it's not relevant to you.
If someone asks a specific question then that probably got a reason for him. And you did not give any argument why it is allegedly not 'meaningful'. Instead you just repeat and repeat it isn't relevant. Explain why it isn't in your imagination. If you don't have any argument for or against it, that's not a meaningful answer either.

And: If you can't explain it simply, you don't understand it well enough. - Albert Einstein


And if you really got no argument at all, then it's extremely disrespectful to the whole forum!

 

[mabat]

Now tell me, ICG. If I use a waveguide with length of zero (i.e. no waveguide at all), what are the limits on it's use?

What prevents me from using a driver with no waveguide at all? Where are the limits then? Doesn't it depend solely on the particular situation in the end? That's what I'm saying but very few seem to understand.

 

[ICG]

Now tell me, ICG. If I use a waveguide with length of zero (i.e. no waveguide at all), what are the limits on it's use?

What prevents me from using a driver with no waveguide at all? Where are the limits then? Doesn't it depend solely on the driver then? That's what I'm saying but very few seem to understand.

Firstly, there's a difference between zero and 7cm. And there are much smaller WGs on tweeters which do have an effect and you know it!

Secondly, your toxic forum behaviour is not acceptable, you did not give any argument why it is 'not meaningful', you are not the standard for everyone to tell what's meaningful and what not. Even worse, if you can't give one single argument for such a wrong claim to give a basis of any discussion!

 

[mabat]

And BTW, I talked about the color of jealousy, not a color of a horn. That you can't understand even such a basic sentence is not my fault.

 

[DonVK]

The question was very clear and relevant IMO.

Matching the sensitivity of the "tweeter" to a woofer, as frequently done for passive XO systems. How low can you cross a ST260 (using the Faital) to match a 97dB sensitivity woofer in a passive XO ? There is enough published data to estimate it.

Based on graphs in these threads below (thanks search engine). We can't use the Faital due to some driver issues but there are 2 other drivers that can be used for the estimate for ST260. Typical sensitivity of 108db leaves us 11dB margin so we just look at where the waveguide LF is down 11dB which is 1KHz+/-100Hz depending on XO.

You will also notice the measured waveguide output starts to drop at 2Khz (compare to RadImp curve) but these drivers have published data that they can go much lower. So the waveguide is the LF limiting factor w.r.t LF sensitivity in these measurements.

- Faital HF1440 resonance issue
Acoustic Horn Design – The Easy Way (Ath4)

- sim data comparison ST260 to ST280E includes RadImp
Acoustic Horn Design – The Easy Way (Ath4)

- Peerless DFM-2535R00-08 measured on ST260
Acoustic Horn Design – The Easy Way (Ath4)

-B&C DE360 measured on ST260
Acoustic Horn Design – The Easy Way (Ath4)

 

[mountainman bob]

Yes, as a forum member who is slightly (ok mostly! ) behind on the technical/engineering aspects I find it rather off putting when a question or statement that may be stupid or irrelevant to most of those in the know is disregarded as such without explanation…….the explanation is the education correct?