New project has come alive. Seas 27TBFC / Peerless 830884 TMM

[Jed]

Finally!


At this point, I'm completely confused. Why should these speakers sound so different to the Natalies? If I had to describe what I heard, I'd say the Nats are more detailed and accurate, and these speakers are far more forgiving and relaxed. But FR seems to say both speakers should sound very similar. I just don't get it.

Have you looked at Off Axis and/or power response and compared that to the NatalieP? I wouldn't doubt that the NatP is flat through the presence region and your design a bit more of a BBC dip through the presence region.

Now that I've worked with metal, ceramic, paper, and various others, I'd say it is valid to suggest they have certain sonic signatures, but it is possible to get similar results if keeping the drivers more in their pistonic range, and also designing around the distortion profiles, such that the higher order stuff is well away from useable passband.

[fjhuerta]

Thanks Jon. I'll definitely tune them lower... perhaps around 24 Hz.

I still wonder whether I should fill the box with dacron. I know this isn't usually done with ported boxes, but I still wonder...

Jed, I do believe you have a point. Off-axis dispersion with the 8" is worse than with the 7" of the Natalies. And, depending on the axis, I get strange phase effects due to the 0.5 woofer. This could be a good reason. I don't think I'll ever try a 2.5 design again... I felt there are no real advantages (other than vertical dispersion) when compared to an MTM, and it's a lot harder to properly design.

[fjhuerta]

Minor update. I tuned them much lower - around 26 or so Hz. I also lowered tweeter level by adding a parallel resistor to the tweeter crossover. Apparently, after break-in, the tweeter level raised a bit. They are now far better integrated, and the boomy lows are completely gone.

I loved working with these drivers. Even though the Peerless were expensive, crossover design is simplified a lot. And they have a gorgeous midrange. The 27TBFC is the best tweeter I've used so far - I definitely like it a lot more than the Dayton RS28A.

[TurboFC3S]

Nice looking design Javier, I'm just starting design phase using some 830884's and Morel Supremo 110's. I considered doing a 2.5 way, but I think I'm just going to do a 2-way transmission line floorstander.

I've done a couple 2.5 ways in the past, they are a bit trickier than it seems they should be. I've found what a couple have mentioned to be very true, add a couple db of BSC into your 1 woofer, and use a MUCH bigger inductor on your .5 woofer. My first 2.5 way I modeled with and started design with a 5.6 mH ... I was pretty green at the time and couldn't figure out where there were so many dips and peaks in the FR below 1000hz, until somebody explained cancellation to me I then went to a 8mH and reshaped the 1 woofer curve, this turned out much better - it really tightened up the image and gave it the ability to cast a bigger stage. So I took it another step and tried a bit more BSC on the 1 woof and a 12mH on the .5, that was what I found to be the best sound of all. I also tried putting a 200uF on the 1 woofer as a high-pass, kinda a pseudo-3way, but couldn't decide if it was better or not. It did seem that the midrange was cleaner, but with a bit less bass output.

I love the sound from the Peerless Exclusives too, they have a very engaging and musical sound ... and you're right, you can crank 'em all day without your ears ever getting tired.

[JonMarsh]

Jon,

Which program is that?

A MathCAD doc I wrote years ago, with the data exported and formatted in Excel.

[TacoD]

Minor update. I tuned them much lower - around 26 or so Hz. I also lowered tweeter level by adding a parallel resistor to the tweeter crossover. Apparently, after break-in, the tweeter level raised a bit. They are now far better integrated, and the boomy lows are completely gone.

I loved working with these drivers. Even though the Peerless were expensive, crossover design is simplified a lot. And they have a gorgeous midrange. The 27TBFC is the best tweeter I've used so far - I definitely like it a lot more than the Dayton RS28A.

Ah, time for the next project!

[fjhuerta]

Ah, time for the next project!

Yeah... the Miniliths, using a Seas CA21REX, the Neo8 PDR, and the Neo3 PDR!

I believe it'll be a real challenge... I'll use them as nearfield monitors, and I *know* their FR is not exactly what I'd call "flat". But hey, it's a great challenge!

[JonMarsh]

Thanks Jon. I'll definitely tune them lower... perhaps around 24 Hz.

I still wonder whether I should fill the box with dacron. I know this isn't usually done with ported boxes, but I still wonder...

Jed, I do believe you have a point. Off-axis dispersion with the 8" is worse than with the 7" of the Natalies. And, depending on the axis, I get strange phase effects due to the 0.5 woofer. This could be a good reason. I don't think I'll ever try a 2.5 design again... I felt there are no real advantages (other than vertical dispersion) when compared to an MTM, and it's a lot harder to properly design.

Actually, I usually "lightly" fill ported enclosures, and line the wall with a good damping material like heavy felt or foam with a weighted vinyl layer.

[peter_m]

fjhuerta,
anything new with your speakers? Have you made more adjustments?