Re: RBR discussion thread

[Clearwave]

The metal is 5.5mm for the recess. Because it has a gasket it may end up being closer to 6.5mm overall.

[Bob Barker]

Earlier this week, I went to Madisound to order the RBR kits, but they showed out of stock. (I was waiting for the original crossovers to come back in stock.)

Will Madisound get these back in stock?
(or will I have to choose a different design (perhaps one of the similar designs using Dayton drivers from PE?)

[Clearwave]

The sale ended because they are out of stock of the Scan Speak drivers used in the RBR. If you want a kit, I have a replacement design, but it's not nearly as inexpensive because the drivers are regular stock items at madisound. So the RBR is no more in the original configuration. Sorry to hear you missed out on the sale. They sold out pretty quick.

[Bob Barker]

Thanks for the info, but not much interested in ScanSpeak at their comparatively high MSRP prices. I just feel there are much better values to be had.

However, some really good deals on ScanSpeak drivers have been coming around at least a couple times a year, so maybe I'll grab some next time.

Then, there's always the likelihood that Madisound will offer another high value "recession buster" type of kit using other high-end drivers at a substantial discount.

The RBR sale lasted for almost two months (started in early Aug), but I had reservations due to the relatively large enclosure size with only a 5.25" woofer. I'd much prefer a 6.5" - 7" woofer for the improvement in bass response, improved efficiency, and higher SPL capability. I could use them in the bedroom, however.

In the meantime, I'll build some nice MT and MTM designs using the buyout Peerless HDS drivers I got (new) at less than 50% off MSRP and shipped for free. Thanks again for the info.

[Clearwave]

In the meantime, I'll build some nice MT and MTM designs using the buyout Peerless HDS drivers I got (new) at less than 50% off MSRP and shipped for free. Thanks again for the info.

Sounds like you've got some nice plans for your next speakers. It's too bad those HDS Peerless drivers have been discontinued because they were a good value even at full price.

Jed

[diynut]

Jed,

Thanks for helping us newbies.

I don't mind getting/using some extra components in the RBR kit crossover
if it's going make a good system better.
Would having impedance flatenning notches for the SB Acoustics tweeter and the SS driver
at their respective resonance frequencies (at say 580Hz and around 30Hz) be helpful to the sound?
If so, should I be notching the SS driver based on its free air resonance or its resonance when
used in an enclosure?
I don't have a measurement setup.

I'm also thinking about reusing a pair of MTWW floorstanding cabinets
for the RBR kit together with the 4 exisitng 10" woofers.
The sealed enclosure on the top is 16 liters while the cabinet width is 11.5 inches.
I'm thinking about crossing the 10" woofers over around 50-70Hz.
Do you see any issues with using the kit in an MT configuration as opposed to TM?
What effects are expected with a cabinet width of 11.5 inches?
Any thoughts/suggestions you have are appreciated.

Thanks in advance for your help.

[Clearwave]

Changing any dimension of the cabinet of the RBR will result in diffraction differences. Therefore the current crossover, which was created after using the measured data of the drivers mounted in that box, will be invalid in an 11 inch wide box. A 3 way will need a completely different crossover as well because it is made up of low pass, bandpass, and high pass filters that interact differently than a simple 2 way (from an electrical and acoustic perspective).

So my final answer is, the 3 way would need a completely new crossover from measurements taken from the new box, and no part or not many parts of the current RBR crossover will be reusable in that passive solution.

Jed

[diynut]

Jed,

Thanks for your thoughts.
It sounds like I should get a cabinet similar to the one specified
if I like to use the crossover that came with the RBR kit.
In that case, would it still help sonically for me to add a series LCR notch at 580Hz
to flatten out the impedance peak of the SB Acoustics tweeter?
Thanks again.

[Clearwave]

Diynut I'll send you a PM.

Jed

[diynut]

Thanks, Jed.

[Clearwave]

If you missed out on the RBR special, I have a new Mk2 version available at a 10% discount off the retail of parts (limited time) including assembled crossovers. Featured is the new Scan Speak HDS tweeter. See my website for details if you are interested in this new kit.