OB Speaker Opportunity

Dedicated to those large boxes at one end of the room
Post Reply
JohnG
Old Hand
Posts: 222
Joined: Sat Mar 25, 2017 10:59 am

OB Speaker Opportunity

Post by JohnG » Tue Oct 23, 2018 9:06 am

A opportunity has come forward to Purchase a OB Pair of Speakers.
They have B&G Neo3 Tweeters ( 93.5 db @ 4 Ohms ) , Fostex Fe 207e , Eminence Alpha 15 x 2 ( Watts ? @ Ohms ? ) Eminence Kappa ( Watts ? @ Ohms ? )
The specs on the bass units are being requested. I have 5 x Eminence Beta 15's on standby following previous advice from here. So I can swap these out if it seems the sensible option.
The OB's on offer will require a XO.
Here is my question, will the above assembly of drivers be able to function as a passive OB ?
The chance to have a functioning OB working at home with limited build effort from my end is a good entry prospect for me.

User avatar
IslandPink
No idea why I do this anymore
Posts: 6959
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

Re: OB Speaker Opportunity

Post by IslandPink » Tue Oct 23, 2018 7:55 pm

Not sure, In my opinion the Em Alphas are too high a Q and loose, so yes, swap in the Betas. The 207e has plenty of choppiness in the low treble with a peak at 2.5kHz ( just where it's least helpful ) so you might find them tiring unless they have been modified. It looks to have a similar character to the 206e which I found caustic, near-axis. There are various Em Kappas around, all highish power, not sure if they would be good or not, or gel with the others. What kind of crossovers does it have for all those drivers ?
Is this a plain flat baffle or have side-wings ?
The flat baffles struggle to get bass up enough without EQ.
"The bass is the king of the instruments - it has no known natural predator" (Wobble)

JohnG
Old Hand
Posts: 222
Joined: Sat Mar 25, 2017 10:59 am

Re: OB Speaker Opportunity

Post by JohnG » Tue Oct 23, 2018 9:44 pm

The vendor has informed me the Alpha's are 8 Ohm @ 400 Watt and the Kappa's are 8 Ohm @ 600 Watt.
There are no XO's with these speakers.
They have a Birch Plywood flat plain baffle.
I can modify the baffle if it is seen to offer a improvement.
I am happy to replace all bass drivers with the all ready owned Beta's, they were purchased with this type of use as their purpose.
I would like to get going with a Passive OB set up, I think the 845 Mono's will enjoy them.
Are these worth a punt as a starting point ?

User avatar
Ray P
Social outcast
Posts: 3064
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

Re: OB Speaker Opportunity

Post by Ray P » Tue Oct 23, 2018 9:55 pm

John, it all seems like just a bunch of compromises to me - why pay good money for something to then just almost completely rework it. I would pass it by.

If you have the bass units already why not just start your OB journey by building (or have built) something along the lines of Nick's simple Quasar project. Should be an easy build and it has a simple passive crossover. Suitable starter Mid/top drive units should be relatively cheap.
Last edited by Ray P on Tue Oct 23, 2018 10:31 pm, edited 1 time in total.

simon
Eternally single
Posts: 4091
Joined: Thu May 24, 2007 11:22 am
Location: People's Republic of South Yorkshire

Re: OB Speaker Opportunity

Post by simon » Tue Oct 23, 2018 10:24 pm

Tend to agree with Ray. Sounds like the vendor is selling you a plank and some drivers. Speakers can be tricky - unless they're a steal I'd consider a more proven route unless you fancy a bit of an adventure.

User avatar
pre65
Amstrad Tower of Power
Posts: 17620
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex

Re: OB Speaker Opportunity

Post by pre65 » Tue Oct 23, 2018 10:32 pm

I agree with Ray & Simon.

Best bet is to go and see our Colin (Topps) and have a listen to his OB speakers. You will not regret it.

Another option (although not OB) is the really good 12" Fane (and the 15" versions) that Steve and Ant have made.
Life is what happens to you while you're busy making other plans. John Lennon

G-Popz THE easy listening connoisseur. (Philip)

User avatar
Ali Tait
Social outcast
Posts: 3615
Joined: Fri Jun 08, 2007 8:10 pm
Location: Dunfermline

Re: OB Speaker Opportunity

Post by Ali Tait » Tue Oct 23, 2018 10:44 pm

Agreed. If you fancy OB’s, go and have a listen to Colin’s. They are excellent.
Image[/img]

JohnG
Old Hand
Posts: 222
Joined: Sat Mar 25, 2017 10:59 am

Re: OB Speaker Opportunity

Post by JohnG » Tue Oct 23, 2018 11:21 pm

Thank you all for your thoughts on this enquiry.
I will be taking the advice given.
I did hope to have Colins OB's hooked up to the 845's, we have had a discussion about a audition at Owston.

User avatar
Nick
Site Admin
Posts: 11886
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

Re: OB Speaker Opportunity

Post by Nick » Wed Oct 24, 2018 8:38 am

If you don’t mind fighting through the junk you are welcome to have a listen to my OB's some time.
Resistance isn't futile it's V / I.

JohnG
Old Hand
Posts: 222
Joined: Sat Mar 25, 2017 10:59 am

Re: OB Speaker Opportunity

Post by JohnG » Wed Oct 24, 2018 2:41 pm

Hi Nick
I would like that, How far into the North will one venture for such a pilgrimage.

User avatar
Nick
Site Admin
Posts: 11886
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

Re: OB Speaker Opportunity

Post by Nick » Wed Oct 24, 2018 3:02 pm

Betwix Bradford and Halifax.
Resistance isn't futile it's V / I.

User avatar
Toppsy
Shed dweller
Posts: 2146
Joined: Mon Jul 23, 2007 12:10 pm
Location: red rose country
Contact:

Re: OB Speaker Opportunity

Post by Toppsy » Thu Oct 25, 2018 2:35 pm

JohnG wrote:
Tue Oct 23, 2018 11:21 pm
Thank you all for your thoughts on this enquiry.
I will be taking the advice given.
I did hope to have Colins OB's hooked up to the 845's, we have had a discussion about a audition at Owston.
John,
You are most welcome anytime to come over to mine for an audition. Bring the 845's so we can hook them up to the OB's.

I don't live too far from Nick's, so you could perhaps combine the two auditions for the same day?

JohnG
Old Hand
Posts: 222
Joined: Sat Mar 25, 2017 10:59 am

Re: OB Speaker Opportunity

Post by JohnG » Fri Oct 26, 2018 2:37 pm

Hi Colin
Thank you for your offer to visit again.
I was hoping to make the Yorkshire Hifi Club, my final jaunt out in 2018.
It looks like I might have to squeeze one more in.
I would also like to hear the latest design you have produced as well.
How easy is it to get the 845's into your home. These amp's ruin me, when shunting them around.
I thought all that pain was over when I got rid of the 9 Stone 401 Plinth.

User avatar
Toppsy
Shed dweller
Posts: 2146
Joined: Mon Jul 23, 2007 12:10 pm
Location: red rose country
Contact:

Re: OB Speaker Opportunity

Post by Toppsy » Fri Oct 26, 2018 6:35 pm

JohnG wrote:
Fri Oct 26, 2018 2:37 pm
Hi Colin
Thank you for your offer to visit again.
I was hoping to make the Yorkshire Hifi Club, my final jaunt out in 2018.
It looks like I might have to squeeze one more in.
I would also like to hear the latest design you have produced as well.
How easy is it to get the 845's into your home. These amp's ruin me, when shunting them around.
I thought all that pain was over when I got rid of the 9 Stone 401 Plinth.
John,
should be straight forward and relative easy, assuming a 2-man lift per amp. Park up on the driveway and we can lug the amps through either the front door or side door straight into my music/listening room.

JohnG
Old Hand
Posts: 222
Joined: Sat Mar 25, 2017 10:59 am

Re: OB Speaker Opportunity

Post by JohnG » Fri Oct 26, 2018 7:02 pm

Sound like a Plan Colin.
I'll chip in for the leccy metre usage.

Post Reply