Do you own Dunlavy SC-IV's AND a yardstick ???

THANK YOU ALL for your responses. I GREATLY appreciate it !!! Sean
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500 Houses! Wow! You are a true purist. I love it! Would love to hear your system. What else is in the system?

Yes. The correction is in the time domain. "Flat" frequency response is actually the "side effect" so to speak of maintaining the time coherence. If you Sigtech correct a non phase coherent speaker more of the processing power goes to correcting the speaker and not the room.

With the Dunlavy all the Sigtech processing goes to minimizing the room effects. With Dunlavy providing the actual frequency and impulse traces for each speaker you can see how close you can come with your in room measurements.

My approach was to first do the best I could in buying a house with a suitable room. (We looked at 500 houses) Then got the best room placement(first approximation with room software). Then basic room treatment(not so basic subfloor reinforcing). Then use the Sigtech correction.

The final result is I've pretty effectively eliminated my room and maintained impulse/phase coherence with flat frequency response from the high 20's to 10K. I could get them flat to 20K but as I said above I prefer the room roll off

Pls1, Dunlavy V's and Sigtech sounds (reads) impressive. May I ask if the Sigtech maintains phase coherence while "correcting"?

Sean, I measured my Dunlavy SC-V’s.

I measured twice so I’m pretty sure that the accuracy is within ¼”

Mine are on the Dunlavy bases which are 2 ¼” thick.

From the top of the BASES (add 2 ¼”) to floor

Tweeter 38”

Mid 31 ¾”

Lower Mid 21 ¾”

Woofer 9 ¼”

The speaker array is symmetrical around the tweeter

I listen with my ear at tweeter level in a bean bag chair. I do not correct the tweeter response with my Sigtech as the slight roll-off above 10K gives me a better listening experience

I have access to MLSSA and other RTA’s including the one that is associated with my Sigtech. In my good sized and moderately treated room they require relatively little correction from the Sigtech and the impulse and frequency response is excellent.

I listen to a lot of live classical music and for orchestral music they are hard to beat.

Let us know how the project turns out.

Yeah, my head was in the clouds for some reason. I was using the wrong conversion ratio when i did all of those equations. Good thing i didn't start sawing wood based upon my "dazed" calculations : )

Having said that, 37" seems a tad low to me for an average seated listening position. I have to wonder what the average height is for someone's ears while seated ??? Sean
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Sean, I am not sure how you arrived with the 43" figure. From conversion...1" to 2.54cm, the tweeter height should be 37.5".

16cm = 6.3"
50cm = 19.7"

Let me know if I am wrong. Thanks

Thanks guys, I appreciate the responses. I'm not so much worried about the tweeter height ( although this is quite important in a focused array ), but the distance that the drivers are spaced apart.

I'm trying to "reverse engineer" some of Dunlavy's science. While i can calculate the effects of comb filtering in theory by doing the math, i'd like to see what John came up with and thought worked good enough in real life to put these speakers into production. Knowing the size of the drivers and the points of crossover / slope rate makes this kind of reverse engineering relatively easy.

Genesis' figures place the tweeter at appr 43", which might be above or below the ear depending on one's own personal height or seated listening position. Since this is a "designed in" factor, one would really have to find some type of seat that would place ones' ears somewhere close to that level.

I also agree with Tom's comments in regards to "typically" liking the tweeter to be slightly above one's ear. Sound does "fall off" as it launches away from the speaker, so sitting with ones' ears slightly below the tweeter actually gives you are response that is closer to being "on axis" in the distance. This will vary somewhat with the speaker design, drivers being used and seated listening distance, but it just goes to show how important speaker selection and speaker positioning really is.

J.D.'s tweeter center at 37" seems a little low, but if one is short in stature, sitting closer to the speakers or has a somewhat sunken listening position, it might be just right. At 6' 3" tall, i would almost have to be sitting on the ground for my ears to be close to this level. Obviously, this is something that J.D. has played around with in his system / room and is happy with the results. Otherwise, i'm sure that he'd still be "tweaking away". Then again, i don't think that layered bubble wrap would do much in terms of supporting these big behemoths : )

For those of you that are doing the math, Genesis' figures center the midranges about 7.25" away from the tweeter and the woofer about 22.75" away from the tweeter or 15.5" away from the center of the midrange. With the shallow slopes that Dunlavy uses, i'd have to imagine that there is a measurable amount of lobing / comb filtering taking place at these distances, but i'll have to do some number crunching and see where this comes out at.

Aaron aka "Aaronm" here on A-gon was also kind enough to email me directly and very graciously offered his assistance. While i would love to take him up on his offer to visit and listen / take measurements of his SC-V's, even very local trips are hard for me to swing at this point in time. If possible, i would GREATLY appreciate it if he would be so kind as to take some measurements for me on the V's. This would give me some info to compare with that of the IV's and let me know if there actually was a method to Dunlavy's madness or if things were done in a more random fashion

Once again, i do appreciate your responses and help. It is good to have someone that you can trust to fall back on when needed : ) Sean
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Sean, I have my IVa speakers without the original bases set on Arios pros and BDR pucks 2 1/8" off the floor, my tweeter is 37" off the floor.

Sean are you needing measurements with the Dunlavy speakers attached to their original bases and resting atop the flooring? I have my SC4's sans original bases resting upon Sistrum SP101's. With these large bases I can vertically and horizontially align the speakers left and right so they will have identical wave launch to my listening position. Sean, I feel having the tweeters about 1/2 inch above the opening of my ear gives me the best in frequency balance and musicality. These speakers are problematic in the bass range. Having two identical woofers with the same crossover point and dissimilar distances to the floor and ceiling boundaries takes much time and effort to converge. I have found ways to minimize this difference in room loading effect. Tom

Sean, having read mst of the posts you have here, I guess it is fair to do my share to the community.

I have my speakers tucked away and these are the best I can do at this time which I think is fairly accurate.

1. approx 94-95cm
2. 16cm
3. 50cm

Hope thi s helps. If you think it is not good enough, email me and I will remeasure it for you.