New New Speaker Project

[Silent Screamer]

The 12MU/8731T00 is 87dB, 3dB down on the 4731... so doubling those will only give me 93 instead of 96...

Also the frequency response is not as nice as the 4731... If I was to parallel the 8 ohm version would I get a 4 ohm curve?

[Silent Screamer]

Just wondering if I was to change the order and get the 8 ohm / 2 = 4 ohm and the 4 ohm has and SPL of 90dB, would an 8 ohm in parallel give me the same SPL as the single 4 ohm (+ the 6dB for double in parallel)?

[dabbler]

I would stick with 8731's in parallel, that is sensitive enough for your purposes. 4731's in parallel is a bit crazy.

Buying 10 (very expensive) drivers you have never heard before is brave! They aren't my cup of tea but I suppose they are easy enough to work with.

[Silent Screamer]

I was intending on buying just 4 but I got a very good deal on them and made it very hard to say no.

Well I am hoping they are not completely foreign sounding to me as the come from the same family as the drivers in my Cremona's.

Will take a while to break them in as it did the Cremona's, I took them out of the box for the first time and listened to them green and they sounded terrible.

I'm going to see if I can split the order and get some 8 ohm for the front 3 speakers, and 4 ohm for the rear where I will use them in singles.

Not sure what I am going to do for woofers just yet I would like to hear what I have sounds like first. I still have the 2 x 10" Vifa's to play with.

Worst case scenario I should still have 93dB with the 8 ohm...

Curious what is it you don't like about them?

[dabbler]

Originally Posted by Silent Screamer

Curious what is it you don't like about them?

They are good drivers, very neutral but I seem to prefer the revelator series.

[audible1]

Hi Screamer, I am a DIY speaker builder in Sydney too!
I am just testing my new 3 way, 10" (seas Mg cone), with planar Neo10 and Neo 3 PDR tweeter (dipolar config).
Good to hear that other people are building speakers in Oz too!
Drop me a line.

Greg

[audible1]

By the way, just read your thread. I also use Digital Xover, (Behringer DCX 2496) in my config with 6 x class D amp from mutichannel input ICEpower amp (from Pioneer amp series). I just received a package from Parts Express today with my passive components, my speaker will have option of normal passive Xover.

I am very interested in your design, I hope you can get a good deal on your scanspeaks!

BTW, as far as bass is concerned I my reflex 10" Seas does definitely go down to 30Hz flat in 100L reflex box. I will verify this with a trace perhaps this weekend.

[Silent Screamer]

Hey Audible1 sounds like you have an interesting project going there, not sure why you would want to have a passive option when you have an active crossover, unless you are using the active to determine the best type of crossover and then going to create passive?

Managed to change my order so now getting 6 of the 8 ohm and 4 of the 4 ohm… will use the 8 ohm in parallel to drive them at 4 ohm. Hoping that they will still have the same frequency response attributes of the 4 ohm drivers.

Organised a new microphone, so will be setup to start doing some testing soon. Lots of reading to be done to find out how to use the active crossover, microphone etc.

Dabbler I like neutral, so I am hoping they sound similar to the 18W Revelator drivers I have in the Cremona’s. That was half the reason I was looking at the Audio Technology drivers, apparently the paper driver still adds some colour to the driver even though it’s not a lot.

I am hoping that the paper of the ScanSpeak helps balance out the metal of the Raal.

Really is a lot of guess work going on here...

[audible1]

Hi Silent,

I have made my speakers active / passive so I can use them with ordinary amps and valve gear. I doubt that the passive version of my speaker will perform as well as the active, but there is always the option to change it over. For that, I am getting double binding posts for each of the woofer, mid and tweets, so I can bypass the passive components out.

I have been using a digital crossover for a couple of months now, also with phase alignment and I have a dayton omnimic (for frequency/ phase / distortion etc). Let me know if I can help you with it. I am keen to know some people who like building speakers (and having fun with them) in Sydney.

BTW, I used to make copied Watt/ Puppies with 18W drivers. Nice, but I think a little overdamped. Used in a lot of high end speakers.

Greg

[Silent Screamer]

Thanks audible1... might pick your brains if I run into trouble with the microphone.

Been away for the last week having a holiday in Queensland. While I was there I spent a bit of time doodling some designs and picking up some more audio equipment.

Might look a bit strange, but the more I think about it the more I like it.

I am looking to isolate the mid and tweeter from the thumping of the bass from the woofer, the stand won't touch the cabinet below.

Still some finishing touches to be done but it's nearly there...