Forum developed GR-R WAW speaker

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planet10

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Re: Forum developed GR-R WAW speaker
« Reply #60 on: 7 Jul 2018, 12:06 am »
You don't thhink the LGK needs any BSC at 200hz+ ?

The width of the box is the primary input into that factor. 200 Hz is going to need ~ 20”+ wide cabinet (on 1st pass), but there are other factors. Our XOs are usually lower than theory would suggest.

Also a factor is how low the midTweeter goes. We tend to put them in an aperiodic midTL that aims to eliminate any effect of the output of the rear side of the cone, but it also means the midTweeter does not reacg as low.

As an aside, aa aperiodic  midTweeter TL enclosure does a good job of lowering the magnitude/fattening the resonant peak making a passive HP filter less problematic.

dave

Folsom

Re: Forum developed GR-R WAW speaker
« Reply #61 on: 7 Jul 2018, 12:08 am »
Oh, and Danny, can I confirm if the M165 is 2.93" insertion depth? It isn't listed, but that's what the other M165 variants are I believe.

Folsom

Re: Forum developed GR-R WAW speaker
« Reply #62 on: 7 Jul 2018, 12:12 am »
Dave can you give me an example of such a midtweet TL setup? A pic? I was hoping to keep it simple but it could be advisable to have an ape vent chamber feeding a TL that's at resonance to help it drop off faster... That is the point, right?

The front baffle is not going to be 20" wide, so I don't see how a BSC is going to be unneeded.

The example WAW speaker you showed earlier at 450hz passive xover obviously wasn't within 1/4 wavelength distance for 350hz.

Danny Richie

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Re: Forum developed GR-R WAW speaker
« Reply #63 on: 7 Jul 2018, 12:31 am »
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At the frequencies involved going active makes things way easier… and depending on how you do it, could even be cheaper.

Dave is correct about that one. And it gives you all the flexibility you need.

Big wide baffles should be avoided. That really hurts imaging and sound stage depth. The LGK doesn't require a baffle any wider than 4.5".

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Oh, and Danny, can I confirm if the M165 is 2.93" insertion depth?

Yes.

And you will need a filter for baffle step loss.

Danny Richie

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Re: Forum developed GR-R WAW speaker
« Reply #64 on: 7 Jul 2018, 12:37 am »
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I use BoxSIM. I put the LGK in a baffle & box size approximate to what this would be with a smaller front on one side. Then I put in the BSC filter you have (approximate) and a 66uf cap to see how it would do. Phase is pretty good, impedance fine, but response does have bit of a dip at 4khz. I suspect that a 66uf cap inline with a 1mH~ inductor could be at 4khz, but I have not checked. The overall response is pretty good, if not maybe a touch lower than expected in the midrange region. How much attenuation did you shoot for to balance it?

I wouldn't put much faith in modeling software. Taking real measurements tells you exactly what's going on.

And the filters needed are easy to design based on the real output. It is much easier and faster to actually put the filters on the speaker and shoot a response than to theorize what is going to happen.

planet10

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Re: Forum developed GR-R WAW speaker
« Reply #65 on: 7 Jul 2018, 12:38 am »
can you give me an example of such a midtweet TL setup?

http://www.planet10-hifi.com/planset/Tysen-V2-extents.gif

It is a simple 10:1 line the depth of the box. As long as it has sufficient volume the other detail are not overly critical.

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That is the point, right?

The point is to completely absorb the rediation off the back of the driver.

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The front baffle is not going to be 20" wide, so I don't see how a BSC is going to be unneeded.

That is a 1st order quess for a 200 Hz XO.

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The example WAW speaker you showed earlier at 450hz passive xover obviously wasn't within 1/4 wavelength distance for 350hz.

That is true, and why the active XO is at 250 Hz. The fellow that did the passive XO took a lot of measures of the drivers in the box and that is where he ended up.



This is the simmed response but after the fact measures showed it to be spot on.

dave

Danny Richie

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Re: Forum developed GR-R WAW speaker
« Reply #66 on: 7 Jul 2018, 12:55 am »
Man, those lower woofers are playing up really high. That could cause a lot of out of phase cancellation in the vertical off axis. There might even be some in the on axis.

That looks like about a 5db peak at 9kHz. I can design a filter to knock that out of it if you like. But then again, it is just a simulation so who knows.

planet10

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Re: Forum developed GR-R WAW speaker
« Reply #67 on: 7 Jul 2018, 01:10 am »
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That looks like about a 5db peak at 9kHz.

A bit bigger on the stock drivers. It does not intrude much being that high up. The Alpair 5.2 is probably smooth up there but wasn’t on the radar when we started these. A wide variaety of 3” drivers could be loaded into that TL including the LGK, and not much change needed to accomodate larger drivers in the Alpair6.2/7.3 class.

The woofers go up to 5k or so on-axis. I had misgivings about the high XO when i 1st got the design, but in practise it works well. Edged out by FHXL, but a much smaller footprint. Bipolar “viewed” on edge has perfect bafflestep fill-in, issues near the XO will be dependent on the off-axis.

The fellow who did the XOs is a measurement based fanatic, these were measured in a big space, with them 20+ ft in the air. That the measured responses after XO were very close to the sim is an indication of how well he did.

dave

Folsom

Re: Forum developed GR-R WAW speaker
« Reply #68 on: 7 Jul 2018, 03:47 am »
I guess the next step is waiting for the measurements from raw drivers in box.

The TL isn't what I thought. I would not use it with this driver, I believe the ape vent will be much better.

planet10

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Re: Forum developed GR-R WAW speaker
« Reply #69 on: 7 Jul 2018, 04:35 am »
I would not use it with this driver, I believe the ape vent will be much better.

2 ways of doing much the same thing.

dave

Folsom

Re: Forum developed GR-R WAW speaker
« Reply #70 on: 7 Jul 2018, 05:19 am »
The LGK has almost no dampening, some back pressure that isn't highly resonate will make the amplifier put on the e-brake better.

Danny Richie

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Re: Forum developed GR-R WAW speaker
« Reply #71 on: 7 Jul 2018, 04:12 pm »
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The fellow who did the XOs is a measurement based fanatic, these were measured in a big space, with them 20+ ft in the air. That the measured responses after XO were very close to the sim is an indication of how well he did.

I am a bit fanatical about the measured responses myself. But while most just look at the on axis response, I look heavily at the horizontal and vertical off axis response to see how well drivers remain in phase over a wide range or if there are out of phase cancellations taking place that might cause an uneven room response.

That design is one that I would be curious to measure myself as I kind of question what will happen in the off axis in both planes.