MiniDSP to fix time alignement in KHorns without biamping

[Bofkont]

Your idea is clever! How did you arrive at 7.5 ms for the delay?

Thanks you're too kind! 7.5 mS is the max. amount of delay you get in the 2x4 unit, with an advanced X-over software package. I have seen figures from 6.0 to 7.5 ms as measurements of delay in the bass bins, so I thought it was not not that critical. And I liked what I heard, so I didn't mess with it anymore. You guys made me aware of the significance of this number, so I'll look into it.

In some of the configurations a miniDSP takes it time to do the arithmatics, but because all signals are run through in my setup it this doesn't create a problem. It would if you'd do tri-amping with the bassbin driven by an unprocessed signal and the mid/highs through the miniDSP. Well not really a problem because you want some delay there [].

The next thing to do is to mount the K77F's on the back of the cabinet and mount some acoustic absorbtion like Basotec around it. Shame, the Anni's look nice as they are. Anybody set them up vertical like their twin EV 350? No need for a baffle probably; better to mount it free I guess?

Best

Dirk

[Bofkont]

Just an update. As others have experienced, for me too a window has opened up. Last Sunday I took the beast apart and took the K77F tweeters out of the top and put them over the mid drivers. Top in front is nicely covered with foam, curtain behind it. Solid silver LSwire in Teflon is hardly visible. I set them up vertically because EV350's were recommended like that. The effect is quite stunning. Immediately you notice the coherence of drums, vibraphone, cymbals and the like. Comparing a mono recording on the tweaked vs standard KH this effect is clearly heared. Thriving on this little success I also tweaked the other tweeter and enjoyed some good stereo sound the better part of the afternoon and getting used to a few dB more highs. A breath of fresh air!

Now voices are clearer too (nil tubiness anymore), they also have a percussive nature I was not aware of, like the rolling RRRR's of Cecilia Bartolia. That is a real percussive sound now! You hear separate tones from a piano more clearly. It is a very gratifying modification.

Turning back the delay in the miniDSP to the recommended 4.44 mS the picture sort of shifted forwards, so I settled for 6.5 mS somewhere in the middle knowing it is very easy to further adjust from the PC.

[Chris A]

I set them up vertically because EV350's were recommended like that. The effect is quite stunning. Immediately you notice the coherence of drums, vibraphone, cymbals and the like. Comparing a mono recording on the tweaked vs. standard KH, this effect is clearly heard. Thriving on this little success, I also tweaked the other tweeter and enjoyed good stereo sound for the better part of the afternoon, getting used to a few dB more highs. A breath of fresh air!,,,I also tweaked the other tweeter and enjoyed some good stereo sound the better part of the afternoon and getting used to a few dB more highs. A breath of fresh air!...Now voices are clearer too (nil tubbiness anymore), they also have a percussive nature I was not aware of, like the rolling RRRRs of Cecilia Bartolia. That is a real percussive sound now! You hear separate tones from a piano more clearly. It is a very gratifying modification.

Good description!

I've also found that if you are off on the tweeter-to-midrange alignment by as little as 1 cm, the result is a shift in timbre that makes it difficult to integrate with Jubs on either side (vis-à-vis with my tri-amped center Belle).

Turning back the delay in the miniDSP to the recommended 4.44 ms the picture sort of shifted forwards, so I settled for 6.5 ms somewhere in the middle knowing it is very easy to further adjust from the PC.

The bass-to-midrange alignment is more than 10x less critical than the midrange-tweeter alignment due to the crossover wavelengths, but I'd be surprised if you couldn't hear a difference of as little as 0.2 ms from measured time-aligned delay. I wonder if some of the forwardness may be related to summing ahead of the preamp/crossover that is beam steering the main output lobes around via midrange-bass horn interaction?

Chris

[Marvel]

I'm planning to get this plugin for my audio software. It will do up to seven bands and up to 96db per slope (each slope is adjusted separately). I like the idea of doing the delays and then summing the outputs back together.

There are some free multiband filters, too, but this one looks to be the easiest to use. Each band can be assigned to a subgroup, with the appropriate delay on each group, and then summed back together.

Bruce

[mark1101]

Bruce, what hardware is involved with that mixer software? Is it like the mini DSP where all the I/O plugs in? Can you do the summing in SW so you don't need the reverse Y adaptors?

[Marvel]

I'm using multitrack audio recording software in a standard Windows PC. This is a VST plugin. They have them for the OSX as well, with a version that should work with Garage Band.

The summing would be in the software and fed out through the sound card (Audiophile 24/96). It is supposed to keep the phase correct with the different slopes. I have a few PCs around that aren't being used, including a couple that are very, very quiet.

---

Blue Cat's MB-7 Mixer is a unique plug-in that splits the signal into
several frequency bands and lets you mix them as if they were separate
tracks.

Each band proposes controls that you can find on a mixing console,
and more: bypass, mute or solo each band separately to isolate
frequencies you want to work on, adjust the gain, the "stereoness" and
the position in the stereo field. When manipulating the stereo image, a
master mono switch also lets you check mono compatibility.

The plug-in also proposes unique linking and grouping options thanks
to our multi-instances technology. You can link bands together within a
single instance or between several instances of the plug-in on different
tracks. This lets a simple fader control as many bands on as many
tracks as you want. This is particularly useful when adjusting the
placement or the balance of several competing tracks.

And as usual with Blue Cat Audio, the plug-in provides comprehensive
visual feedback to let you know what's exactly going on: for each
channel, monitor the spectrum, the in/out levels and the frequency
response.

--

A link to the online manual is here:

http://www.bluecataudio.com/Doc/Product_MB7Mixer/

I don't have the $120 at the moment, but the rest is here at the house.

Bruce

[mark1101]

Neat..........that looks like the answer. So you just match the crossover points of your speakers and add the appropriate delays?.........Let us know how it sounds.

[Marvel]

So you just match the crossover points of your speakers and add the appropriate delays?

Correct... that is how it should work. I want to try different slopes to see how the signal is impacted when going back into my passive crossover on my LS. I currently have a low order crossover my LS, since I am using a 2A3 amp. The higher order crossovers tend to use a bit more power.

Bruce