Open Baffle Epiphany!

[Bonkers60]

It doesn't appear from looking up the Marantz, that it has a line out. If it did, you'd be in business with it. If you use the tape loop, you won't have control over the volume to the sub with the main volume knob.

But yes, the plate amp appears to have the ability to loop through it for the bass duty and come back to an amp. What you bring back, it does not give you as a high pass, so your full range speakers will be running full range with the woofer augmenting the FR. This means either you need to provide some other means of rolling off the lows to them, or keep an eye on the total excursion of those drivers.

EV3

I am planning on using the crossover on the plate amp. Will this do what you are referring to? It sounds like this amp is popular for open baffles, so I was assuming that it had the proper functions. I am not sure that I totally understand it.

 

[davidro]

So I've got a couple of Audio Nirvana 15" cast frame drivers. The cabs will arrive a few weeks later. I wanna try out the OB for fun before they arrive. What measurements MDF panels do I need? Thickness etc? And what's the easiest and cheapest way to get them stand on the floor? Bearing in mind the drivers are fairly heavy.

Cheers
D

 

[MJKing]

When you say high Qts drivers are you thinking +.50Qt or as in +1.00? I think it makes more difference with an OB.

I like woofers with Qts values of about 1.0 for dipole speakers. I have used woofers in the 0.8 to 1.2 range and been happy with the results. The woofer, the baffle (OB,U, or H), and the crossover will determine your low end response. These high Qts drivers do not need EQ like a low Qts woofer.

 

[MX117.MC7150]

That is really really hard to say. Depends on what co-ax you use, and what you expect. I bought these speakers to use with an Electra Print 300B Custom amp, which is good for 8 wpc. Efficiency of the co-ax is 94 dB, and the crossover is 6sB per octave with Alpha Core coils, Clarity caps, and Mills resistor. It sounded nice with the EP gear, but a bit too warm and romantic for my taste, that kind of classic British sound.

I experimented with a few things. but what finally did the trick for me was a 33 wpc Class A battery powered amp based on a Nelson Pass A40 circuit, along with an active SS pre-amp. I found the c combination to have the majority of that SET magic and yet open the top end up in a way that the tubes didn't. Hersey I know, as I have used SET for over a decade. But this is what worked for me.

As far as a narrow baffle, these are around 15 inches wide as I recall. They are good for 50 hertz, and then I roll a subwoofer in. The narrower the baffle, the less bass extension you are going to get. So its a trade off.

Regards
Mister Pig

Thanks.
My SET 572-3 based monobloc amps pump out a strong 20wpc. If does not work, have a 40wpc PP amp to give a try.
Am wondering if a single coax might not be the way to go, as I have a powered sub doing nothing at the moment.
Our no-longer-with-us local OB builder used a super-tweeter with most of his builds. Some of his builds were 6' wide, or more. Easy enough as he had 20x30 'sound room' attached to his house. As he described, it was to try to make up for the warmth involved with the rolled off top end. Some of the super-tweeters he had out of Japan were several thousand$$, each. Same for some of the full-range single drivers.

 

[Poultrygeist]

I am planning to build a set of OB's. I have ordered a pair of Fostex FE126En full range drivers to get started. I am trying to understand the amp hookup that I will need. I am planning to use a Marantz 1030 integrated amp for the full range drivers, and a Yung SD200 for two 15" Eminence Alpha's, one per baffle.

Should the preamp out signal on the Marantz be sent to the Line In on the Yung? then, should the line out on the Yung be sent back to the Marantz amp? Hope my question makes sense. If I understand properly, is the Yung a single channel amp? looking forward to building my first set of DIY speakers. I will post a picture of my baffle plan once I have finished it.

A single Yung SD200 driving two Alphas should give you plenty of power. Another option to feed both the Yung and the Marantz is to use Y cables off the source ( CDP, DAC etc ).

 

[evsentry3]

I am planning on using the crossover on the plate amp. Will this do what you are referring to? It sounds like this amp is popular for open baffles, so I was assuming that it had the proper functions. I am not sure that I totally understand it.

Is this the same as the Marantz 1030 you are referring to?

http://www.classic-audio.com/marantz/1030.html

If so, I do not see a preamp output. Or is there a more recent model with the same designation? A tape loop output is not the same as a preamp out as it does not have the volume control prior to it's output. Yes, you get audio out, but it will be the same level all the time. If so, how would you keep the bass at the right level to match the main speakers?

In looking at the wording on the plate amp, it makes it sound like the RCA out's are a loop through function. If that's correct, then the line level coming out is not high pass filtered. IE...the bass is not rolled off. They are apparently just making the same audio be able to wire onto another amplifier. All that means, as I said before, is that you have to pay attention to the mains still having that full range signal coming back to them. With smaller full range drivers, that can be a problem and require you to remove the low frequencies you have the bass unit using.

EV3

 

[Poultrygeist]

The Yung out's are pass through and I've use them to daisy chain.

 

[cubdog]

So I've got a couple of Audio Nirvana 15" cast frame drivers. The cabs will arrive a few weeks later. I wanna try out the OB for fun before they arrive. What measurements MDF panels do I need? Thickness etc? And what's the easiest and cheapest way to get them stand on the floor? Bearing in mind the drivers are fairly heavy.

Cheers
D

I'd just use a half sheet of MDF. 3/4"x24x48. A couple of 12 inch l brackets should hold things up.

cubdog

 

[rogerfederer]

david,

if you are just trying this out you could do cardboard reinforced with 1 inch insulating foam board. that is how i tried out different OB configurations initially. allows you to try the JE Labs and winged baffle approaches, for example.

 

[Mister Pig]

Thanks.
My SET 572-3 based monobloc amps pump out a strong 20wpc. If does not work, have a 40wpc PP amp to give a try.
Am wondering if a single coax might not be the way to go, as I have a powered sub doing nothing at the moment.
Our no-longer-with-us local OB builder used a super-tweeter with most of his builds. Some of his builds were 6' wide, or more. Easy enough as he had 20x30 'sound room' attached to his house. As he described, it was to try to make up for the warmth involved with the rolled off top end. Some of the super-tweeters he had out of Japan were several thousand$$, each. Same for some of the full-range single drivers.

Well I think that is plenty of power for the Hawthorne Sterling Silver driver, I take it that is the one you are considering? There are a few other co-ax drivers out on the market that are used for open baffle speakers, such as the P Audio. Actually if I were doing this from a scratch build, I think I would go with the woofer only version of the Sterling Silver, and use the Heil tweeter, cloning the upper end builds such as those Rainier speakers. But I think OB speakers sound good enough to warrant investing that kind of money. But the devil is in the details, and the crossover makes or breaks a multi driver speaker in most cases. The Hawthorne forum should have the resources to plan out the needed x-over if you don't go the path of generating your own computer modeled x-over.

When setting this system up I did run the coax speaker by itself, and it can be done with decent results. But it is my opinion that you want the bass drivers on the same plane as the coax, resulting in a cohesive presentation down to 50 hertz or so before you add the sub in. Actually I gave the same set up as you described a go, with an Infinity sub and the coax playing. I had to bring the sub up to a higher crossover point than I liked.

Remember though, this is a post from a pig that normally deals with single driver speakers and SET amps. This is my first multi driver speaker in a few years, and my first OB speakers. There are others that have way more real world experience on building these. I am just passing on my observations of listening.

Regards
Mister Pig

 

[tomlinmgt]

david,

if you are just trying this out you could do cardboard reinforced with 1 inch insulating foam board. that is how i tried out different OB configurations initially. allows you to try the JE Labs and winged baffle approaches, for example.

With all due respect, I don't think I'd trust cardboard and foam board to support a 15" AN driver that has the ferrite magnet (assuming that's what you have coming, David). I suspect they weigh considerably more than something like a low buck 15" woofer (Alpha 15A, for example). I go with what cub suggests or thinner baffle material with full height vertical support struts on outer edges of baffle. Knowing you're a little limited wrt tools/workplace, the precut 3/4" MDF and some BIG shelf brackets would work well for you.

 

[cubdog]

My 8 inch Audio Nirvanas weigh more than the 15 inch Eminence drivers. Somewhere around 9-10 pounds a believe. Those 15 in ANs must be quite heavy indeed.

cubdog

 

[rogerfederer]

good point re the weight. i was trying cardboard/foamboard with 8" betsys.

 

[Mister Pig]

I suspect a $20 sheet of OSB or mdf would be worth the investment if you want to experiment...no reason to risk the expensive drivers to damage....

Regards
Mister Pig

 

[PR Audio]

What type of issues should I be looking for? It does appear that I do have the proper connections.

Sorry, I assumed the Marantz 1030 had the same Inputs and Outputs as the 1060, that only the WPC changed. I was wrong in my assumption.

The Marantz 1030 does not have a Pre-Amp Output and Amp Input, like the Marantz 1060. You will have to use the Tape Loop, but you will have no volume control, but the advantage of the Yung plate amp is that it has it's own Line Level control, so you can lower it; it is not a volume control, so even at it's minimum setting it might not be enough. This would be a trial and error deal.

 

[PR Audio]

i suspect a $20 sheet of osb or mdf would be worth the investment if you want to experiment...no reason to risk the expensive drivers to damage....

Regards
mister pig

+ 1

 

[PR Audio]

A single Yung SD200 driving two Alphas should give you plenty of power. Another option to feed both the Yung and the Marantz is to use Y cables off the source ( CDP, DAC etc ).

If a receiver or integrated amp has bridged PRE-AMP Output and a POWER-AMP Input. Would it be safe for the equipment to use a Y-Adapter to feed the signal to two (2) amps (ie. the integrated/receiver plus a separate power amp)? (Same concept applies to a Pre-Amp feeding two (2) Power Amps)

Sorry, for the "newbie" question, but getting into bi-amping a pair of DIY speakers, though I'm using an active x-over, so no need for Y-Splitters.

 

[davidro]

oh yes these drivers are mofo heavy asses...i can't rely on cardboard panels!
i think i'll go mdf route....hopefully i'm motivated enough

I'd just use a half sheet of MDF. 3/4"x24x48. A couple of 12 inch l brackets should hold things up.

cubdog

what's l brackets cub??

 

[cubdog]

oh yes these drivers are mofo heavy asses...i can't rely on cardboard panels!
i think i'll go mdf route....hopefully i'm motivated enough



what's l brackets cub??

L bracket. Shaped just like the letter. Sorry I should have capitalized it.

cubdog

 

[davidro]

like this right?