ScanSpeak 2-way with waveguide

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Hi Everyone,

I've made a 2-way stand-mount called Revelation Two - Monitor WG.

The Revelation Two - Monitor WG uses one of my favorite mid-woofers the ScanSpeak 15W/4531G00 and the Dayton Audio RS28F-4 tweeter in a Visaton WG148R combo.

There are three versions of the cross-over, the Simplistic, the Perfectionist and something in between, the Intermediate.

Each of them is a valid option and can be chosen according to personal taste and e.g. room placement. In my opinion each extra step to the Perfectionist cross-over adds additional sonic qualities, but for the cross-over purists the Simplistic version is nice. 🙂

For further details see: Revelation Two - Monitor WG

Regards

/Göran
 

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Interesting, as ever, Goran! 5" plus 1" seems to be the only speaker with enough overlap on driver response to get away with LR2. You've given it a decent sized box too. Most speakers like this are too small IMO. Lumpy bass is bad. 🙂

I'm seeing huge interest at this forum in the Earl Geddes type waveguide currently. It solves the time alignment problem one way. And matches dispersion too. I'm thinking that SEAS DXT tweeter might also be good too in this sort of speaker.

You start to appreciate what designers like our own tinitus (RIP) aka Lars Dyreborg and Duke LeJeune are up to here:
 

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I'm thinking that SEAS DXT tweeter might also be good too in this sort of speaker.

I've done a DXT design here Prestigious Two – Monitor DXT. The DXT tweeter is good, but not as good as the "hype" around it.

The RS28F-4 and the Visaton WG148R combo is much better in my opinion.

Many of the commercial waveguide designs I've listen to haven't caught in to me, but after many requests I gave in and made a waveguide design that I actually like. 😉

I don't think it will be the last either.

I really like how elegant simple the cross-over works with the Dayton and Visaton combo.

Regards

/Göran
 
I built the MKI with the D2608 last yr and that was the best implementation of that tweeter that I have come across! Up till that point I was very disappointed in it. Unfortunately, I had already committed the tweets to a friend's build so it was a temporary bliss. (Side note, mine were Peerless models from ~2008 and maybe the sensitivity has changed with SS but I had to pad the tweeter down quite a bit)

David
 
Nice design, if they are truly 87dB then they can't have much, if any BSC built in, which would be fine for close wall mounting.

It's good to see another wave guide design out there. Especially using one that seems very easy to use. It's also nice that you've tried using a different wave guide to the ones that people typically use. The Visaton does indeed measure pretty well and keeps the top octave issues that one normally sees, pretty benign. So here we have another nice wave guide for the DIY community to get its teeth stuck into.

The 5" Scan is a no brainer for high performance (it'll be interesting to see how the new 5" Satori performs when it finally gets here) and I like the fact that you've combined it with a tweeter that offers a nice balance of performance vs price. This should hopefully prove quite popular!
 
Nice design, if they are truly 87dB then they can't have much, if any BSC built in, which would be fine for close wall mounting.

I'm using the 4 Ohm version of the Revelator. The Perfectionist version of the cross-over have almost a full BSC. The Revelator in this baffle configuration doesn't need much BSC. See the attached picture for raw frequency response on that baffle (frequency response valid down to 275Hz).

Yes, you are right the 87dB 2.83v/1m estimate is a bit optimistic even though the mid-woofer have a bit higher sensitivity than the official specs. 😉

I will make new calibration measurements to get a better estimate.

It's good to see another wave guide design out there. Especially using one that seems very easy to use. It's also nice that you've tried using a different wave guide to the ones that people typically use. The Visaton does indeed measure pretty well and keeps the top octave issues that one normally sees, pretty benign. So here we have another nice wave guide for the DIY community to get its teeth stuck into.

Yes, the Visaton waveguide is very easy to use, but it takes a lot of testing to find suitable tweeters for it. Of about 8 tweeters tested I found two that works well, the Dayton RS28F-4 is one of them and I'm continuing searching for more candidates.

The 5" Scan is a no brainer for high performance (it'll be interesting to see how the new 5" Satori performs when it finally gets here) and I like the fact that you've combined it with a tweeter that offers a nice balance of performance vs price. This should hopefully prove quite popular!

Yes I'm also waiting for the Satori 5", even though it's more like a 4.5" than 5".

The 5" ScanSpeak Revelator on the other hand has the nicest natural roll-off and smoothest frequency response I've ever measured in this size and it's very easy to design cross-overs using it.

Regards

/Göran
 

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I built the MKI with the D2608 last yr and that was the best implementation of that tweeter that I have come across! Up till that point I was very disappointed in it. Unfortunately, I had already committed the tweets to a friend's build so it was a temporary bliss. (Side note, mine were Peerless models from ~2008 and maybe the sensitivity has changed with SS but I had to pad the tweeter down quite a bit)

David

I'm glad you liked the MkI. 🙂

Yes, I've seen some variations in the HDS tweeter. I've helped other people who had this tweeter and I've seen both frequency as well as sensitivity variations.

This makes me a bit reluctant to use it in designs, which is a shame since it's a nice tweeter.



/Göran
 
Yes, the Visaton waveguide is very easy to use, but it takes a lot of testing to find suitable tweeters for it. Of about 8 tweeters tested I found two that works well, the Dayton RS28F-4 is one of them and I'm continuing searching for more candidates.
Göran,
could you share what other tweeter worked well, and also the non suitable ones?
TIA, Ralf
 
I'm using the 4 Ohm version of the Revelator. The Perfectionist version of the cross-over have almost a full BSC. The Revelator in this baffle configuration doesn't need much BSC.

The 4 ohm Rev has a half space sensitivity of around 87dB and regardless of what baffle it is placed on, unless it's gigantic, it is always going to experience 6dB of loss towards low frequencies when placed in completely free air. You're likely to only see 5dB when the loudspeaker is placed well away from side walls in a room. This should place the end sensitivity of the Perfectionist version at around 82dB.
 
I understand your point for the "good" tweeter. But why not saying which tweeters weren't suitable for this waveguide? It could save time to us diyers, without having to reinvent the wheel trying to do the same thing you already did.

Ralf
 
The 4 ohm Rev has a half space sensitivity of around 87dB and regardless of what baffle it is placed on, unless it's gigantic, it is always going to experience 6dB of loss towards low frequencies when placed in completely free air. You're likely to only see 5dB when the loudspeaker is placed well away from side walls in a room. This should place the end sensitivity of the Perfectionist version at around 82dB.

Hi,

Yes, I'm fully aware of how the baffle step works. My point with the picture was to show how smooth the response is above the baffle step and with a rather narrow baffle. Compare the Revelator to the Satori in picture1 in a similar baffle setup. Both are good, but in my opinion the Revelator excels in frequency response.

As I mention before the ScanSpeak 15W/4531G00 Revelator has a higher sensitivity than the official specs. In fact >2dB.

I've done a new level calibration of my measurement equipment and here's some clarification regarding the system sensitivity depending on the cross-over versions.

Below the baffle step the Perfectionist cross-over have a sensitivity of about 86dB 2.83v/1m.

The measurements are made at tweeter heigt, on-axis @ 1m distance and is valid down to about 270Hz:

Picture1: Red=Revelator vs. Blue=Satori on-axis response normalized to the same SPL
Picture2: Blue=Simplistic, Red=Intermediate, Green=Perfectionist x-over
Picture3: Blue=Intermediate, Red=Perfectionist x-over, Green=87dB marker
Picture4: Blue=Intermediate, Red=Perfectionist x-over, Green=Raw frequency response
Picture5: Blue=87dB marker, Red=Perfectionist x-over, Green=Raw frequency response

Regards

/Göran
 

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I understand your point for the "good" tweeter. But why not saying which tweeters weren't suitable for this waveguide? It could save time to us diyers, without having to reinvent the wheel trying to do the same thing you already did.

Ralf

Just about any tweeter which hasn't a flat face plate and a smooth transition to the mouth of the waveguide. Here's a few from the top of my memory:

  • The HDS tweeter
  • The small flange Scanspeak Illuminator tweeters
  • The Scanspeak AirCirc tweeters
  • The Scanspeak Classic tweeters

Some are worse some are better. Some would perhaps work better with additional modification to the waveguide, but I haven't tried that. I might publish some of the results if I find the time.

The Dayton works great and only needs new screw holes. Besides that I think it looks great in the waveguide, if that matters. 😛

Regards

/Göran
 
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