OB Design for use with small SETs

[IslandPink]

The more I read about the big OB projects with 15" drivers, the more my sub project ( IPL SW3 ) seems to be stalled ! I've got a load of 25mm MDF in the hall getting in the way, too .

Hmmm...

MJ

[NickG]

I think from what I remember of your room Mark (when it wasn't taken up with amplifiers), the OB's would be nice. The 15" units certainly make nice bass, with no sound of anything having to work hard (not supprising driving a 200W speaker with 3W). I think the next eggfest should be interesting, though I may have to use someone elses amplifier, I don't think I can fit these and the 211 in the car at the same time :-)

[andrew ivimey]

Nick, I was thinking of giving the Ongaku a day out.

As any fule no, It is a good enough amplifier to show off what a) 211s can sound like and B) what a good SE amp can do relative to all these strange push pull jobbies.

Just a thought .... all these 45s strewn all over the floor. All weedy, p-nuts but very sweet. I intend to bring one of my (Gordon Rankin) 45 brews too and of course am very keen to hear these new 'OB' designs.

[NickG]

That would be good Andrew. My prototype JIBBOB's (James Insipired Big Bass Open Baffles, everything else seems to have a name :-)) are connected to my old A&R A60 playing CD on repeat at the moment, they may not be finished by November (whatever is), but hopefully they will be there.

[James D]

Boy that should be good The Ongaku would seriesly boss then about! I want to try Metallica on the JIBBOBs!

James

[andrew ivimey]

Ohhhhhhhhhhhhhhhhhhhhhhhh Goddddhhhhhh arrrrgh, no, not METALLICA. Run for cover, lock up your women.

Here's a thing. Heavy duty bass. There are a couple of tracks I use to see just how low and how fast speakers can go. One is a track by David Gray where he is singing (if you can call it singing) strumming a guitar, a beat box is playing for a rather odd rhythm (the chap is not a drummer) with an appallingly low sine wave bass note. Played loud, this track can seriously confuse some amplifiers / speakers as the low sine wave pulses modulate the singing. A sign of poor amp and / or poor speakers. In an SE amp my guess is that the PSU isn't up to the power requirements to tackle this wide range of sound.

Metallica is something else entirely; more like being slammed against a brick wall at 130mph. HARD. 'orrible

[James D]

Guess we'll have to try it after that!

[IslandPink]

Superb work Nick . Are you on proper chokes yet or have you bodged something ? How many bits required for the crossover ?
I will bring my amp, which has moved on a fair bit since last Eggfest . Maybe I can even get a better power supply built ( ? shunt or borrow some chokes for a Dave Dove style low DCR conventional ) .
Are you going to try the phase plugs too ?

Mark

[James D]

The JIBBOBs are very simple just a choke and a cap - choke in parallel with the Fostex and cap in parallel with the Beta. I'll let Nick account for his bodges

Looking forward to hearing your amp again :-) Lets try it with Metallica too

[BOONDI]

Originally Posted by andrew ivimey

Here's a thing. Heavy duty bass. There are a couple of tracks I use to see just how low and how fast speakers can go. One is a track by David Gray where he is singing (if you can call it singing) strumming a guitar, a beat box is playing for a rather odd rhythm (the chap is not a drummer) with an appallingly low sine wave bass note.

Hi Andrew, all...

This track by Mr Grey caught me by surprise too. Gut churningly low bass thwack is the best way to describe it. I have to say that my system coped well with it, but the power and speed of it surprised me....
Didn't think my system went as low.....