OB Speaker Opportunity

Dedicated to those large boxes at one end of the room
Post Reply
JohnG
Old Hand
Posts: 418
Joined: Sat Mar 25, 2017 10:59 am

#1 OB Speaker Opportunity

Post by JohnG »

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
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#2 Re: OB Speaker Opportunity

Post by IslandPink »

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.
"Once you find out ... the Circumstances ; then you can go out"
JohnG
Old Hand
Posts: 418
Joined: Sat Mar 25, 2017 10:59 am

#3 Re: OB Speaker Opportunity

Post by JohnG »

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
No idea why I do this anymore
Posts: 6294
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

#4 Re: OB Speaker Opportunity

Post by Ray P »

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.
Sorry, I couldn't resist!
simon
Thermionic Monk Status
Posts: 5600
Joined: Thu May 24, 2007 11:22 am
Location: People's Republic of South Yorkshire

#5 Re: OB Speaker Opportunity

Post by simon »

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: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#6 Re: OB Speaker Opportunity

Post by pre65 »

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.
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
Ali Tait
Eternally single
Posts: 4373
Joined: Fri Jun 08, 2007 8:10 pm
Location: Galashiels

#7 Re: OB Speaker Opportunity

Post by Ali Tait »

Agreed. If you fancy OB’s, go and have a listen to Colin’s. They are excellent.
JohnG
Old Hand
Posts: 418
Joined: Sat Mar 25, 2017 10:59 am

#8 Re: OB Speaker Opportunity

Post by JohnG »

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: 15707
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#9 Re: OB Speaker Opportunity

Post by Nick »

If you don’t mind fighting through the junk you are welcome to have a listen to my OB's some time.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
JohnG
Old Hand
Posts: 418
Joined: Sat Mar 25, 2017 10:59 am

#10 Re: OB Speaker Opportunity

Post by JohnG »

Hi Nick
I would like that, How far into the North will one venture for such a pilgrimage.
User avatar
Nick
Site Admin
Posts: 15707
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#11 Re: OB Speaker Opportunity

Post by Nick »

Betwix Bradford and Halifax.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Toppsy
Shed dweller
Posts: 2400
Joined: Mon Jul 23, 2007 12:10 pm
Location: red rose country

#12 Re: OB Speaker Opportunity

Post by Toppsy »

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: 418
Joined: Sat Mar 25, 2017 10:59 am

#13 Re: OB Speaker Opportunity

Post by JohnG »

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: 2400
Joined: Mon Jul 23, 2007 12:10 pm
Location: red rose country

#14 Re: OB Speaker Opportunity

Post by Toppsy »

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: 418
Joined: Sat Mar 25, 2017 10:59 am

#15 Re: OB Speaker Opportunity

Post by JohnG »

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