RSS315HF-4 as the anchor of a 3-way???

[Pete Schumacher]

Re: RSS315HF-4 as the anchor of a 3-way???

Boys boys boys . . . settle down now!!! :p

Hey Ryan,

Thanks again for the help.

Keep in mind that the need for a notch is especially important for an acoustic alignment like Troels used in the Ellam. He's got an LR4 @ 2800Hz implementation, which requires a flatter response to a higher frequency than the LR2 at 2200 I've got in the Byzantium. The Scan is already rolling off in the LR2 at 800Hz, but not in the Ellam. Without the notch, I can easily see how there could be too much energy at 800Hz.

I've been in the process of trying to get the measured data of the individual mid and tweet to line up with the combined response plot.

I traced the plots we took of the Scan and RS28, extracted minimum phase, and plugged them into the PCD model. The result was nothing like the measured combined response.

The only way I can get them even close is to actually push the acoustic center of the Scan forward of the tweeter by approximately 15mm, which is an interesting result in and of itself. Doing that seems to produce a plot that resembles the combined measured response reasonably well.

Since doing that, I've played around with the tweeter HP inductor in PCD, and with what we measured, a .25mH in place of the .5mH seems to do wonders for the phase match, as well as bring that area around 1KHz down. I wonder if some of that forwardness wasn't just the woofer being low, or even an issue with the Scan, but of too much contribution from the tweeter at that point. It's resonance is right where you were discussing the forward sound. Knocking down that inductor to .25mH reduces the tweeter output at that point by more than 5dB while only reducing the 1KHz summed level by 1dB. I've got some .25mH inductors laying around. I think I'll drop them into the circuit and give 'em a listen.

Stop by with your ears and tell me what you think!!! ;)

[DoubleTap]

Re: RSS315HF-4 as the anchor of a 3-way???

I've been listening more here at home Pete and feel more confident in what I said earlier. A lot of the same songs we listened to yesterday that would come forward in the stage don't do that here.

As far as the culprit I'm not 100% of what it is, but am using past experience as a guide ... both with the 15w and speakers in general. When a vocalist can go from deep behind the speakers to instantly in your lap during a dynamic passage, that's the upper midrange. That's what I call a forward presentation, excess tweeter energy I call brightness. Since it is a 3-way instead of the 15W handling bass, it could be that the 15W needs attenuation over it's entire band ... however male vocals not doing that makes me believe it's an upper midrange issue, and should be handled by a notch. My past experience with 80+ 15W's makes me think the same thing.

If a speaker measures flat but still comes forward on you, what are you going to trust? Your ears or the mic?

[DoubleTap]

Re: RSS315HF-4 as the anchor of a 3-way???

Just one more thing to add Pete, if you think I'm nuts with this 'forward' thing then tell me so. Once the woofer balance is right, I'd agree they're 98% of the way to perfect ... if you think it's more like 100% then I'm cool with that too.

They do sound fantastic right now, no doubt about that. Even to me the majority of songs we heard after the changes, I couldn't find fault. But sometime soon you should come over here and compare for yourself.

[Pete Schumacher]

Re: RSS315HF-4 as the anchor of a 3-way???

I'd have thought that the measurements would at least hint that there was excess energy at 800Hz. The graph above shows the opposite, a slight trough at 800Hz.

I don't have the parts on hand to make the notch. Got a pair of 3mH inductors and 18uF caps? It would be easy enough to drop them into the circuit to see what they do. I've got plenty of resistors around to vary the notch depth.

And I don't think you're nuts. Everything you've suggested so far has improved the sound.

[DoubleTap]

Re: RSS315HF-4 as the anchor of a 3-way???

Hey, listening to a FIM recording ... Masters of Chinese Percussion. We GOTTA try this cd out on your speakers. It'll give those 315's a workout like nothing yet!

[DoubleTap]

Re: RSS315HF-4 as the anchor of a 3-way???

I'd have thought that the measurements would at least hint that there was excess energy at 800Hz. The graph above shows the opposite, a slight trough at 800Hz.

I don't have the parts on hand to make the notch. Got a pair of 3mH inductors and 18uF caps? It would be easy enough to drop them into the circuit to see what they do. I've got plenty of resistors around to vary the notch depth.

Exactly, measurement can bite me in this case ... especially since it's not like we sticked to strict best practices measurement protocol.

Just try the EQ'ing first and see what you think. If you like the result I imagine I do have whatever xover parts we'd need.

And I don't think you're nuts. Everything you've suggested so far has improved the sound.

I do have some $120 AC power plugs, so maybe just a bit nuts ;)

[Pete Schumacher]

Re: RSS315HF-4 as the anchor of a 3-way???

Exactly, measurement can bite me in this case ... especially since it's not like we sticked to strict best practices measurement protocol.

Just try the EQ'ing first and see what you think. If you like the result I imagine I do have whatever xover parts we'd need.

I'll notch 800 a dB or two and see how it goes. I made the tweeter mod already, and put the .25mH in place of the .5.

I do have some $120 AC power plugs, so maybe just a bit nuts ;)

And some people have diamond encrusted Rolexes. Doesn't make them crazy . . . doesn't mean they're necessarily more punctual either . . . ;)

[DoubleTap]

Re: RSS315HF-4 as the anchor of a 3-way???

I'll notch 800 a dB or two and see how it goes. I made the tweeter mod already, and put the .25mH in place of the .5.

One thing at a time daddio ... post up the PCD shot of what exactly the .25 vs .5mH does again please. And how for down is the tweeter at resonance?

And some people have diamond encrusted Rolexes. Doesn't make them crazy . . . doesn't mean they're necessarily more punctual either . . . ;)

True dat!

[Pete Schumacher]

Re: RSS315HF-4 as the anchor of a 3-way???

One thing at a time daddio ... post up the PCD shot of what exactly the .25 vs .5mH does again please. And how for down is the tweeter at resonance?



True dat!

Haven't tried the notch yet.

Before the .25mH change



After the .25mH change. Notice the deeper reverse null.


And a comparison before and after.

[DoubleTap]

Re: RSS315HF-4 as the anchor of a 3-way???

That looks like just what the Dr. ordered Petey!

[Pete Schumacher]

Re: RSS315HF-4 as the anchor of a 3-way???

That looks like just what the Dr. ordered Petey!

So far, so good. Played a bunch of Nora and Sarah McL and have been enjoying the tracks. We may be on to something here.

[dlneubec]

Re: RSS315HF-4 as the anchor of a 3-way???

Hi Pete,

If you guys didn't previously, you might want to try taking some off axis measurements. Often that will can you some things you don't see on axis in terms of any forwardness, etc.

I found a notch was needed on the 15w's I used in the Duo-S, which is a 2-way with 8531K01's (IIRC) and D26nc55 tweet in a shallow (1/2") waveguide, FWIW, though in that case the difference was easy to see in the simulations as well. It was also semi-omni in presentation. I've attached a simulation comparison of that XO with and without the notch on the scan. I don't believe I ever listened to it without the notch, however.

That said, it looks like you've already adressed this issue. I also don't recall any midrange forwardness to Wolf's scandivifias, so I'd say he conquered that issue with some other trickery in his series XO.

I'm glad to see you are getting great results Pete. I'm looking forward to hearing them at Iowa! I've had plans for a couple years to design a similar all passive speaker but with the pair of TC1000's I have instead of the RS315's. I had even thought about pairing them up with the 15w and RS28F, so it could be very similar undertaking and result.

[Pete Schumacher]

Re: RSS315HF-4 as the anchor of a 3-way???

After listening to the setup with the extra low end on the EQ simulating what the 4 Ohm driver would do, I just found the extra low end a bit too much. So . . .

Made a couple more mods now that we have some measured data. Woofer level was a little lower than anticipated by about 1dB, so rather than drop a RSS315HF-4 into the mix, I just dropped the level of the mid a little more and altered it's high end roll off somewhat to reduce the peaking between 5 and 6KHz caused by the extended high end of the 15W.

I am really pleased by the result thus far. I'm about ready to call this done, and stick with the 8 Ohm version. Check out the impedance plot, as well as the rest of the sim from measured data. Yeah, I'm throwing away maybe a couple dB of sensitivity, but that's just fine with me. These things rock as is. I don't notice the forward character on some female vocals anymore, and the balance top to bottom seems right.

Another day or two listening and then it's time to finish the cabinets.

[gordoncalder]

Re: RSS315HF-4 as the anchor of a 3-way???

Well thank you Gordon. I can't imagine you being the least bit disappointed with the RSS315HF-4 in your three-way. The 8 Ohm version is excellent at reproducing the range from 300Hz down. I can certainly see doing another version of this in a simpler rectangular enclosure with the RS150-4 for the mid for an All Dayton killer 3-way.

What do you have in mind for your project?

Hi Pete,

The RS315-4 sub is the only driver already bought at this point so my options are open. I'm thinking of using the sub sealed, the tweeter will probably be either the Seas 27TBFCG or the DXT, and for the midrange I'm leaning toward the SB acoustics 15NRX-8 (88dB) or the 4-ohm version at Solen (91dB). My progress is pretty slow though, so by the time I'm able to build it someone else may have done it already. Hmm - that could save me a lot of work :-)

I was wondering...have you added up the price of your crossover yet? Everytime I start thinking about a 3-way design, the crossover starts to get into the range where I think I may as well go for one of the active digital options (behringer/ minidsp, etc). The 8ohm steel-lam inductors at madisound are $24 each!. I know your goal was a passive design, and there are lots of good reasons to do that, but for me, well, I guess I'm on the fence - and looking for an excuse to fall off of it.

And whatever enclosures I make, they're going to have to be a whole lot simpler than what you've got there... I'm still trying to master the rectangle! :-)

Gordon

[Pete Schumacher]

Re: RSS315HF-4 as the anchor of a 3-way???

Hi Pete,

The RS315-4 sub is the only driver already bought at this point so my options are open. I'm thinking of using the sub sealed, the tweeter will probably be either the Seas 27TBFCG or the DXT, and for the midrange I'm leaning toward the SB acoustics 15NRX-8 (88dB) or the 4-ohm version at Solen (91dB). My progress is pretty slow though, so by the time I'm able to build it someone else may have done it already. Hmm - that could save me a lot of work :-)

I was wondering...have you added up the price of your crossover yet? Everytime I start thinking about a 3-way design, the crossover starts to get into the range where I think I may as well go for one of the active digital options (behringer/ minidsp, etc). The 8ohm steel-lam inductors at madisound are $24 each!. I know your goal was a passive design, and there are lots of good reasons to do that, but for me, well, I guess I'm on the fence - and looking for an excuse to fall off of it.

And whatever enclosures I make, they're going to have to be a whole lot simpler than what you've got there... I'm still trying to master the rectangle! :-)

Gordon

I've got three iron core (well, a P-core and two iron cores) and two air core inductors in each XO. Then there's the very large poly caps, a pair in each XO and various others. All told, around $100 for each XO. I can definitely see the desire to go active when approaching a three-way. Those low frequency components especially do get quite expensive. But $24 for a iron core inductor? http://www.parts-express.com/pe/psho...66-568&scqty=1 PE's got Mad beat bad.

I've got a good suggestion for you on cabinet materials. Lowe's has MDF stair treads that are the perfect size, and over 1" thick. One edge is routed, but that is easily removed.