Bob Brines, Mark Audio T7-A7

[xrk971]

Well, there is another way...


HIFI Electronical 2 Way Crossover PCBA ClassA Power Linkwitz Riley filter 4 Channel Output Crossover point 2.2K Hz Free Shipping-in Other Consumer Electronics from Consumer Electronics on Aliexpress.com | Alibaba Group

The seller claims it can sell with whatever freq needed. Yes, more expensive, but right on the mark if it does that

I agree this board sounds very interesting. It would be good to have a 12dB/octave LR board too.

 

[tilroh]

Maybe it's just that I'm not accustomed to near field listening...
But the Mark Audio 7.3s in B.Brine's cabinets make me break out in a big grin.
They seem to produce high sound levels without sounding loud/painful.
With bass assistance they might be too good! heh.

 

[misuspita]

I agree this board sounds very interesting. It would be good to have a 12dB/octave LR board too.

Upon closer inspection, it seems they are using there the name of ESP... could it be a clone of this product? If so, we can change the freq of the crossover ourself with a bit of changing resistors/caps

Linkwitz-Riley Electronic Crossover

 

[tilroh]

They certainly cloned the phase shift image.

 

[planet10]

With bass assistance they might be too good!

Indeed.

dave

 

[chrisb]

Yes, those are one of my favorites, but not a desk top/ near field application

 

[tilroh]

Just when I'd gotten those images out of my head you go and post them again.

Build creep has started already. I ordered that XO above. I ask them to X it at 100hz b/c my subs won't be near the BB MTLTs.

 

[xrk971]

Let us know how that XO works out. I would be interested in ordering one with xo freq at 250Hz to 350Hz range which seems to coincide with most of the projects I have given baffle width in the 10 to 12 in range and drivers under consideration.

 

[tilroh]

Delivery for the XO will be in 39 days so I've got time to build the subs.
I looked around and found SB ACOUSTICS 8” WOOFERs for $AU110.ea.

Is this driver suitable for smallish boxes?
I'm not trying to reproduce explosions and earthquakes only fill out the bottom.

Here are the specs.

Order Code SB23NRXS45-8
Type Papyrus
Power 60Wrms
Impedance 8Ω Nom. (Re 5.6Ω)
Sens. 89dB
Re 5.6Ω
Qms 5.4
Qes 0.41
Qts 0.38
Vas 94.0L
Sd 216cm²
Fs 27Hz
Zn 8Ω
Le 0.60mH

Sb23nrxs45 8, Sb Acoustics 8? Woofer, Sb Acoustics | Wagner Online Store

I plugged the numbers into online sub-woofer calculators and got very different results. I don't know enough to use them.

I'm happy to buy plans from someone who has done this before.

Thanks, Mack

 

[xrk971]

If you are looking to make a FAST with an 8in woofer, check out what I did here:
http://www.diyaudio.com/forums/full-range/273524-10f-8424-rs225-8-fast-ref-monitor.html

The Dayton RS225-8 has very similar specs to the SB driver you mention. It's a work in progress but I am getting closer and closer to a final configuration that I can live with for a long time. They sound great - plays all genres well.

 

[zman01]

Dayton woofers available in Australia:

http://www.theloudspeakerkit.com/lo...-drivers-by-type/woofers/?cn=96&pgnum=3&rf=cn

 

[tilroh]

Dayton woofers available in Australia:

Loudspeaker Components Loudspeaker Drivers Woofers

Zman - Thanks! Looks like the metal cone goes lower than the paper but the paper is slightly more expensive. Wonder what the trade off is?

 

[vinylkid58]

Is this driver suitable for smallish boxes?

Looks like the Dayton will give you about the same response, but in a 10l smaller enclosure if that helps.

jeff

 

[xrk971]

That RS225 is quite a driver - I have not been able to find an equivalent in another brand. It has unique properties that allow it to serve as an excellent bass reflex or sealed woofer (with LT) in a fairly compact cabinet.

 

[vinylkid58]

They're pretty cheap at PE too!

jeff

 

[zman01]

Btw, the Dayton Classic woofers are quite cheap (6.5" units are around 1/2 price of the reference series), but at the cost of higher distortion. They have been termed as "euphonic" by a designer for mid-bass applications... however this is a FAST case and XO will be lower... so

Guys,

If OP is crossing really low (100-200 Hz) will it matter a lot?

I know X likes low distortion products 🙂

 

[xrk971]

Zman - Thanks! Looks like the metal cone goes lower than the paper but the paper is slightly more expensive. Wonder what the trade off is?

The paper cone has less breakup at high frequencies if you plan on xo at high frequency as with conventional dome tweeter. But if using in FAST with low xo, the metal cone is nice.

 

[xrk971]

Btw, the Dayton Classic woofers are quite cheap (6.5" units are around 1/2 price of the reference series), but at the cost of higher distortion. They have been termed as "euphonic" by a designer for mid-bass applications... however this is a FAST case and XO will be lower... so

Guys,

If OP is crossing really low (100-200 Hz) will it matter a lot?

I know X likes low distortion products 🙂

For 8in Classic it has only 4.5mm xmax vs 7mm. That is something you need lots of for a FAST woofer. But otherwise the Qts, Qms, etc are similar. Classics are quite nice for $25.

 

[tilroh]

Today was slow at work as you can see by my many posts.
It was also an expensive day. I ordered the XO and just ordered 2 Dayton Audio RS225-8 8" Reference Woofers.

Thank to everyone for their suggestions and input. I'm really excited about adding subs to my B.Brines M.Audio 7.3 MLTLs.

Next is to find out about ported/sealed and size compromises.

Yay! Mack

 

[xrk971]

Tilroh,
Glad you were able to get the Daytons in Australia. If you make your own analog op amp Linkwitz transform circuit, you could add it to signal path of woofers after XO and before amp. Otherwise you will need vented. My calcs show a 23 liter to 24 liter cabinet tuned to 38 Hz works well. You get decent group delay still. Make sure you have ability to physically move your A7 cabinet back and forth relative to bass cabinet for time alignment. My estimates say you may need to set the A7 about 3inches behind the RS225.