Big waveguide, small midrange

[PKAudio]

T25B as is. I already have project with 12MU and T25B without WG, it is excellent combination, sonically. Just be careful with Bliesma crossover, this small Bliesma does not like low Fc. For LR2 and Acoustic centers alignment you will need front baffle tilt ~8deg.
Straight baffle also provides good results, but to achieve good phase tracking LR2 is not possible and you will need to implement ~LR4.

Here you can see what to expect from DXT, it measures great, but this was one of the project I gave up, and replacement of DXT brought immediate relief and improvement though measurements were not so great.
https://pkaudio.webnode.cz/sb17dxt/

 

[TulseLuper]

T25B as is. I already have project with 12MU and T25B without WG, it is excellent combination, sonically. Just be careful with Bliesma crossover, this small Bliesma does not like low Fc.

Thank you.

I plan to use DSP crossovers via Hypex FusionAmps, so time alignment should not be difficult.

 

[PKAudio]

That definitely allows more flexibility with crossover slopes experiments.

 

[Trdat]

The waveguide I am using is the Elsnore Waveguide from Custom Analogue Audio which has a very long thread on DIY audio forum about the DIY speaker its used in, so if the size of the waveguide needs to be as large as the woofer in my DIY case with the mid woofer which is a 4 inch where is the measurement of the width of the waveguide taken from? The size of the inlet to the outlet of the guide seems very small on this waveguide.

This is an accepted design but if anyone can explain why in this case it will work with a guide so small for the tweeter or what the tradeoffs are in this case?

My design is a 3 way using DSP it seems the hardest part is the lobing issue as the waveguide is large in it size dictates and I need to crossover lower but Joe the designer of the waveguide recommends a crossover closer to 3000 while taking in consideration the lobing a lower crossover would be more appproaprate. Anyway, I digress I just want to make sure that this waveguide will work with a 4inch midwoofer?

 

[PKAudio]

Effective area of the WG is roughly defined by R40. With WG depth 18mm this could be good directivity and CtC alignment match to various 4inch midwoofers.

 

[Trdat]

Effective area of the WG is roughly defined by R40. With WG depth 18mm this could be good directivity and CtC alignment match to various 4inch midwoofers.

That is good news, I mean I didn't doubt it just thought it was kind of small. But when you say R40 what is that exactly? I tried googling but didnt bring up a definition per se.

 

[PKAudio]

See waveguide drawing, R39.5 (radius).

 

[Trdat]

See waveguide drawing, R39.5 (radius).

Thanks.

One more question while I am at it, would some degree of a rounded chamfer around the 4 inch midwoofer also help with directivity? Like the midwoofer below?

 

[PKAudio]

That rim around midwoofer is likely just cosmetics and/or just protection of the midwoofer. It may affect FR around 1-2kHz, either to create some wobbles or linearize the response, it depends on woofer's natural response. But KH engineering is good, so I would not expect they would introduce the solution leading to worse performance.
It will have very low impact to directivity, especially if crossover frequency is around 500Hz (not sure now what is exact Fc).

 

[Trdat]

That rim around midwoofer is likely just cosmetics and/or just protection of the midwoofer. It may affect FR around 1-2kHz, either to create some wobbles or linearize the response, it depends on woofer's natural response. But KH engineering is good, so I would not expect they would introduce the solution leading to worse performance.
It will have very low impact to directivity, especially if crossover frequency is around 500Hz (not sure now what is exact Fc).

Thanks for this, I had another thread about my design its will be similar to the Troel 3WC which I have for R/L and making a centre speaker using DSP and adding the above waveguide on the tweeter. If there is little effect on the midrange FR having some type of guide thats great just simplifies my CNCing. My 8 inch will be crossed over around 500hz can go lower or higher. I think key will be the crossover over point of between the tweeter and midrange.