I've built a proven speaker design, but I am a bit unhappy with my crossover setup so far.
The drivers are two Beyma 15p80nd and a Beyma TPL150H in MTM configuration. Slotport top and bottom on the front baffle.
The original designer recommend a 4th order Linkwitz-Riley 900Hz crossover. I have that set in my DSP (DCX2496), but I can hear the transition is quite muddy.
I have access to REW so I can measure the response, but don't really know how to measure and what information is relevant for crossover design. Any pointers?
The drivers are two Beyma 15p80nd and a Beyma TPL150H in MTM configuration. Slotport top and bottom on the front baffle.
The original designer recommend a 4th order Linkwitz-Riley 900Hz crossover. I have that set in my DSP (DCX2496), but I can hear the transition is quite muddy.
I have access to REW so I can measure the response, but don't really know how to measure and what information is relevant for crossover design. Any pointers?
I can only agree to what jerome69 write - I wouldn't choose such a low crossover point for the Beyma TPL-150H driver. I am looking at 2-2.5kHz based upon my own measurements:
Robert GS
An externally hosted image should be here but it was not working when we last tested it.
Robert GS
On and off axis FR, phase and distortion. You're running active, so impedance isn't that much of an issue. Lots of good stuff on the site about the measurement process, so a search should sort you out on that aspect.
However, I agree with the other posters, I think you're trying to push the drivers too far, and a good mid would sort out the problem.
900 Hz is way too low!!!
I am running a Acoustic Elegance TD15H with a Beyma TPL-150. I have mine crossed at 1.2 kHz and that may be a little too low.
Best performance seems to be at and above 2 kHz, but a 15" directivity will be too narrow to match the TPL-150 at that frequency.
The woofers you have selected look like they will play higher up the spectrum, but there is no data on the directivity for the woofer. I can tell from my own measurements that the TPL-150 is a very, very wide directivity driver at 1 kHz and above and my AE speaker starts to get narrow at the same frequency.
I would try setting your crossover at 1.5 kHz if you do not need to play high volumes as a start. At that frequency you can get away with a second order slope or higher. Then you can move that crossover point upward until you get what you like. Bear in mind you will lose directivity in that region.
Lastly, check your TPL-150 polarity with respect to the woofers and the crossover so that there isn't a phase suck out.
It's the TPL150H, the one with the horn.
The original design is with the two woofers at the bottom, horn on top and two rearfiring ports. That design is very successful with a 900Hz crossover, I've heard it myself in two different setups.
Is there a reason the MTM config is different?
I have the speakers on stands to get the horn at earheight.
The original design is with the two woofers at the bottom, horn on top and two rearfiring ports. That design is very successful with a 900Hz crossover, I've heard it myself in two different setups.
Is there a reason the MTM config is different?
I have the speakers on stands to get the horn at earheight.
Here is a link for the actual driver specs:
http://profesional.beyma.com/ingles/pdf/TPL150H.pdf
http://profesional.beyma.com/ingles/pdf/15P80Nd.pdf
http://profesional.beyma.com/ingles/pdf/TPL150H.pdf
http://profesional.beyma.com/ingles/pdf/15P80Nd.pdf
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You may copy the successful setup ie the crossover ?
900Hz can work with a passive crossover, not with a regular active crossover. It is possible with active but complicated at 900Hz. The crossover will not be full LR4. The 15" is done to work till 5kHz
This is shocking for a lot of people. I also heard a 15" could be fullrange, till 20kHz.My initial 900Hz crossover was a copy of one of the successful builds.
I tried raising the crossover to 1,2kHz, and that cleaned up the midrange, but introduced a little harshness that I imagine will become fatiguing in the long run. I better get REW out and do some measurements so I know what I'm doing.
Any particular measurements I want to look at besides FR?
I tried raising the crossover to 1,2kHz, and that cleaned up the midrange, but introduced a little harshness that I imagine will become fatiguing in the long run. I better get REW out and do some measurements so I know what I'm doing.
Any particular measurements I want to look at besides FR?
That "harshness" could be a break up mode, or could be a peak in the frequency response.
If a peak then you can notch it out using the DCX. You need to identify the frequency of the peak and the height of the peak and the width of the peak, so that you can tell DCX what correction to apply to the signal.
You may copy the successful setup ie the crossover ?
900Hz can work with a passive crossover, not with a regular active crossover. It is possible with active but complicated at 900Hz. The crossover will not be full LR4. The 15" is done to work till 5kHz
No 15" will match the directivity of the TPL-150 or TP-150H (doesn't matter) at 1 kHz and up.
The woofer may have a great response on-axis, but physics will intervene at some point due to the size of the radiating surface.
Discontinuity of the power distribution will result above 1 kHz. What that means is the SPL on axis response will be fine, but the power distributed off-axis will peter out until the TPL-150 takes over above the crossover point.
If you look at the polar plot you will see a narrow waistline at the crossover point if it is too high because there is nothing the woofer contributes to the off-axis response.
You need to get on-axis and off-axis horizontal response to find out what is happening.
That TPL-150H spews a lot of sound out ±90 degrees of the horn mouth, by design. That sound is what you hear reflected off surfaces of the room. If the woofer does not match the TPL-150H at the crossover point you actually hear a slight null or suck out at that point.
Also, measurements will determine how the box and placement of the drivers in the box interact and impact the frequency response. This includes diffraction artifacts inherent with the enclosure.
Be forewarned, getting reliable measurements is not an easy task. I have often stated that a DIY Audio forum dedicated to measurements would be a good thing for builders.
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