Can someone please model these speakers?

[Adriel]

BIB enclosure
Fr=Fs=45Hz
Vas=87,30
Qts=0,25
Qts'≥0,338
Vb=308,65L
Internal dimensions - 18,87"(D)x13,34"(W)x74,80"(H)

Faital Pro 12FH500
https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=151050100

Markaudio CHP-90/Markaudio CHR-90
https://www.markaudio.com/online_shop/ch/chp-90/

My biggest concerns are the performance of the pairing and driver excursions (low cut needed?), followed by a need for cross over points, and lastly a curiously of frequency response.

Thanks in advance. 🙂

 

[Richard Ellis]

The biggest concern of the pair is the radical differences in sensitivity, the twelve inch running at 97 Db,...and the little full-ranger at only 89.23 Db. The 12 inch will dominate the little one so much so, you won't even hear the other.
You can drop the crossover as far as about 80 hertz, letting the fullrange do most of the work...the 12 inch to do the deep bass. Frankly, you have a lot of work to do to make these two work together.

------------------------------Rick...

 

[Adriel]

Rick, thank you! 🙂


What be the highest difference between the two, please?

 

[Adriel]

Here is the second highest at 89,645 dB:
https://www.kjfaudio.com/wp-content/uploads/2017/02/Alpair_10P_Gen.1.pdf

And the highest at 91,730 dB:
https://www.markaudio.com/wp-content/uploads/2021/11/Alpair12P.pdf

If neither is an option, then need parameters of what will, please, so can hunt up replacement(s).

 

[AllenB]

Using the drivers in your first post, it will be good to have 7dB difference if you can have them cross around the baffle step. Any left over you can use for a slight bass boost. You can change the crossover frequency by changing the width of your box. It depends on how well you can extend the bass using the volume of the box.

 

[Adriel]

@AllenB , thank you for the help. 🙂

I am not aware of a baffle in a BIB, just a divider to fold the horn in half. If this is a baffle, it is "frozen" at 13,34"/82,46cm width by the Fr=Fs. I have to take a moment to figure out the length.

So does this means the 7dB will not work?

If not, how about 5,27dB difference?

 

[AllenB]

Use the width of the front..

 

[AllenB]

So does this means the 7dB will not work?

It's OK, it only changes the frequency. Let's work that out first.

 

[Adriel]

And what height?

 

[AllenB]

Best to decide that first. Then you can simulate a baffle and get an idea of the frequency.

 

[Adriel]

"Internal dimensions - 18,87"(D)x13,34"(W)x74,80"(H)"
So, that means 1/2 of 18,87" is 9,435, giving the point where the baffle ends. Therefore
=sqrt((65,365^2)+((18,87/2)^2))
=66,04"

 

[Adriel]

Assuming it is the length, not the height at right angle to the floor. Doubt makes a huge difference, though I have yet to model it.

 

[Adriel]

I had to be looking at the line to see in a midrange trough it raised just over the thickness of the line width. 🤣

I was going to say if the model is correct, it is almost about a 7dB boost after 275Hz, just entering the midrange, horn without a filter then goes to 336Hz, though the formula doesn't show the dB roll off.

 

[AllenB]

Exactly, so above that region your fullrange will have enough sensitivity to keep up. You could probably cross anywhere above that and I know @planet10 is keen on crossing WAW (Widerange and woofer) speakers around 250Hz.

 

[planet10]

250-450 Hz, althou i have a wide box that d=is 200 Hz.

The higher you cross the louder you can play, lower means more of the range is covered by a single driver.

Take the CHN-50, MA used something very similar in their SOTA speakers crossed at 2kHz, Scott would have preferred something lower 500-800 Hz, they can be used practically as low as 250 Hz, FR in a good reflex (tiny) F6 to say 65-75 Hz, lower in a horn or TL. Limited volume.

dave

 

[Adriel]

Exactly, so above that region your fullrange will have enough sensitivity to keep up. You could probably cross anywhere above that and I know @planet10 is keen on crossing WAW (Widerange and woofer) speakers around 250Hz.

Okay, really appreciate resolving if this pairing be a great choice.

The fH (if recalling my abbreviations correctly, @Scottmoose and @GM been sharing a lot with us) is 336Hz.

Curious, would a reduction of 2dB make any noticeable difference? My guess be no and might have the opposite being a larger size (further from a tweeter).

 

[Adriel]

@planet10 Dave, this is where a model be so helpful, see the range of both drivers, particularly the 12" and the affect of filters.

All this is finally tracking (there might be a pun there😛).

Which driver?

Volume meaning watts input?

As I understand, the volume control on the amplifier reduces the maximum. Not sure if linear or not.