Scan Speak Reference Plus help!

[Egen]

Sorry for my english...
I decided to make Scan Speak Reference Plus as on http://www.audiocomponents.nl/speake...rence_eng.htm.
But i want to use scan speak D2904/7100 tweeter instead 9900.
And the question is: how to make over the crossover for it.
(in 9900 we have 6 ohm and sensivity 91 db and in 7100 we have 4 ohm 94 db).
thanks a lot!

[Jay_WJ]

You'll need to completely redesign the tweeter network to use a different tweeter, with which we cannot help here.

Why do you think the 7100 is necessarily better than the 9900? If I were you, I'd build the original design as is.

[BNK]

Originally posted by Egen
Sorry for my english...
I decided to make Scan Speak Reference Plus as on http://www.audiocomponents.nl/speake...rence_eng.htm.
But i want to use scan speak D2904/7100 tweeter instead 9900.
And the question is: how to make over the crossover for it.
(in 9900 we have 6 ohm and sensivity 91 db and in 7100 we have 4 ohm 94 db).
thanks a lot!

The ref plus is an amazing speaker and the 9900 works amazingly there. I don't think you should replace it.
If you want to use the 7100 build the Ultimo.
If you do want to replace it, I suggest you to use an active setup (tri-amping with a DCX2496 and 6ch amp).

To design a good crossover for the 7100 to work with the ref plus such as the 9900 works there is a hard to do, especially if you do it for sound quality rather than learning.

[Egen]

But why smb couldn't help me redesign the tweeter network ?!

[BNK]

It's a lot of work, building, testing etc.
Pro's get a lot of money for that.
You can order a custom made design (which is far then ideal) at Madisound for like 40$.

If u will do it, test it with both designs. I'm totally sure that with the 9900 it will sound better!

A redesign might be needed for the woofers xover as well as the cut freq might be different (and thus the whole xover).

Good luck anyway.

[Tenson]

It would be hard for anyone to do it over internet as you will need real life measurements of the tweeter in the speaker to start the design process of the crossover.

[Egen]

and what will be if i only change the attenuator?

[Jay_WJ]

It won't work since the two tweeters' impedance profiles are different.

I just looked at the crossover schematic of the design. I also simulated its tweeter net transfer function using a similar looking impedance file I have. Looking at the 9900's FR and the transfer function, I think this design's crossover frequency is at the lowest 2.5 kHz LR4.

Crossing this good tweeter only at 2.5 kHz? It's possible depending on a design. But honestly, if I were you, I'd build a plan designed by a serious DIY'er rather than a vendor-provided plan. I usually don't trust vendor-provided kits/plans. They simply want to sell their parts. I don't think these designs are created with as much care as serious DIY'ers give to their own designs. Using top notch drivers alone doesn't make it a good design.

[BNK]

Originally posted by Jay_WJ
It won't work since the two tweeters' impedance profiles are different.

I just looked at the crossover schematic of the design. I also simulated its tweeter net transfer function using a similar looking impedance file I have. Looking at the 9900's FR and the transfer function, I think this design's crossover frequency is at the lowest 2.5 kHz LR4.

Crossing this good tweeter only at 2.5 kHz? It's possible depending on a design. But honestly, if I were you, I'd build a plan designed by a serious DIY'er rather than a vendor-provided plan. I usually don't trust vendor-provided kits/plans. They simply want to sell their parts. I don't think these designs are created with as much care as serious DIY'ers give to their own designs. Using top notch drivers alone doesn't make it a good design.

This design isn't made by a vendor (scan speak) but by a serious designer (DIY'er).
I built that kit and it sounds amazing IMO.
It beats a lot of serious designs and off the shelf loudspeakers (and expensive ones).
Personally I designed some boxes with revs, but I would like to test some other serious designs (any recommendations?) vs my designs.

[Jay_WJ]

Originally posted by BNK

This design isn't made by a vendor (scan speak) but by a serious designer (DIY'er).

Oh, really? I didn't know that. The website simply shows a bunch of plans with a variety of SS drivers without any detailed explanations about the designs. That's why I thought so.