MJK’s Jordan JX92S OB with a Goldwood GW-1858 Woofer in an H Frame

[oktyabr]

Thanks Godzilla! Your build certainly helped inspire me... feels like lurking but I bet I've read every word you've written on the OB topic on this forum

@T101 Thank you too! I played various types of music through them for almost 14 hours yesterday and yes, I do believe they loosened up some sounding deeper, fuller. I played the tracks I started with again at the end of the day it certainly seemed so. My Audio Nirvana's sounded terrible out of the box when they were brand new. It took maybe 100 hours before they really started sounding sweet... I've read the Alpha 15s seemed to like some time to limber up, figured the GW's might be the same with that pleated surround.

About the position of the fullranges on the OB, well it seems too off center this leads to uneven horisontal dispersion diagram. You probably designed the mounting position with EDGE, but it simulates only on axis response Have it in mind and consider new OB's in the future, especially if you find yourself struggling to align the H frames with the OB's.

You think so? I actually *have* noticed a bit more trouble getting them aligned right, compared to when they lived in the middle of a bass reflex box. And you guessed correctly. The final baffle position was a compromise between what EDGE said would work the best and up around ear height. That's an 18" wide by 24" tall baffle, the center of the 8" driver is 6" in from the nearest edge. Your suggestion for a different top baffle?

Thanks on the M-65 comment. I like it quite well. Used to have an M-80 too but a friend talked me into selling it to him. I do like the DTA-100 t-amp on top and have been running the Nirvana's with it for quite some time. Didn't think it would have the juice and control to power that 18" very well at low frequencies (?) I do feel a bit funny putting the M-65 to use just running the bottom few octaves but at least I know it's capable! I also have a 150wpc MOSFET based amp (BIAMP Eminence 300) but it likes to get pretty warm and I'm using it to help damp my turntable as well

...But it also brings up a good question. What are people running these H-frames with? I know a few are using plate amps and I think MJK even tried some tubes on his passive version... Being the less efficient of the two speakers I wonder what the minimum power conditions are that an 18" H-frame could live with happily?

 

[DaveCan]

[QUOTE But it also brings up a good question. What are people running these H-frames with? I know a few are using plate amps and I think MJK even tried some tubes on his passive version... Being the less efficient of the two speakers I wonder what the minimum power conditions are that an 18" H-frame could live with happily?[/QUOTE]

Nice project I was using a Reckhorn A400 sub amp but it wRecked itself lol, so now using this Dayton amp Dayton Audio SA240-B 240W Subwoofer Amplifier with Boost 300-805

The GW H-Frames sound really good as subs/augmenters crossed around 70-80hz, using mine at approx 70hz and down.. To me they don't sound good at all crossed any higher and especially up where the vocals start to chime in.. Really love them dialed in with my fe108ez BIB's which are left to run full signal.. Love the clean accurate lows from the GW presentation, and really appreciate Martin and his work for sharing these.. The price, performance, diy ratio, really shines with these in my application, so all in all this dude is a Happy Camper

 

[Russell Dawkins]

The GW H-Frames sound really good as subs/augmenters crossed around 70-80hz, using mine at approx 70hz and down.. To me they don't sound good at all crossed any higher and especially up where the vocals start to chime in..

I'm wondering what slope you are using at 70-80 Hz. 6dB/octave?

 

[DaveCan]

It's a 24db octave slope . I think the H-Frame design works great at the lower frequencies, but certainly colors the the sound at higher frequencies or where the vocals start to sound in for reference etc.. The driver is inset in H-Frames by quite a few inches/centimeters in most cases, and all that box surrounding the driver does not make for a good recipe at higher frequencies imo.. As a low frequency/sub OB solution they work pretty awesome.. I don't ground pound with my drivers so I don't know how well they crank to 11, but from low listening to moderately loud they work and sound really good to me I like that they also convey the detail at lower listening levels as some drivers seem to need to be cranked up to get there... I've recently just moved so this is all my individual experience in my old living room.. The place I moved to just a few days ago has a larger living room, but I have to do lots of work in here before I can set up (prepping, sanding, painting, flooring etc), so it will be awhile before I can set up again.. For now I'm making due with my laptop and clock radio lol

 

[Godzilla]

>>> I think the H-Frame design works great at the lower frequencies, but certainly colors the the sound at higher frequencies...

>>> As a low frequency/sub OB solution they work pretty awesome...

>>> The place I moved to just a few days ago has a larger living room..

I agree with the above. I also moved the H-frames from a smaller room to a larger room and everything sounds great. Just dial in the sub amp and enjoy. H-frames, when crossed over too high, sound bad. When tuning with a sub amp, just set the crossover to 50hz and increase the volume until you hear them. Sit back and listen a while then adjust to taste in small increments. I think mine are set to around 60 or 70hz and the volume knob is not too high.

 

[kees52]

I had a plan to make a H-frame with the Goldwood GW-1858 but this woofer is not in holland, maybe someone here now where, there are here more dutch diy people so let me now. shiipng costs are very high. so maybe a store here can combine them with others like eminence

it looks like this H-frame sounds better then a TL.

thanks

 

[kees52]

Hi There

I have buy the worksheets from martin, but it needs some learntime to get use to it.

I have some question, some worksheets has Sd:= sq cm, and others have Sd :=pi/4 (number mm2), what must I do with that, it is very confusing, why is qts in sheet qtd etc.

Maybe someone now, I want to use 4 eminence alpha in H frame above each other but I have the speakers not yet.

this is what martin tell me about the problem.

Hi Kees,

The variable Sd is the area of the speaker cone. If you put in a number with units of volume the MathCad worksheet will not function. In the BIB worksheet, the cone area Sd is calculated in terms of the 65 mm cone radius. You can enter Sd as a single number with area units or as a calculation.

So I need cone radius of eminence, but why not Sd:= cm2, and has cm2 need to also put in, how haha, cm with the 2 above in mathcad reader won,t work.

wel, I think to read some stuf from martin for learning, I am a amp designer, so box is something new.

thanks

 

[quynhhung]

Sorry! My english is poor.
In my country ' difficult to find goldwood 1858. Can you suggestion woofer for replacement best. Beyma 18lx60v2?.
BR!

 

[Greg B]

The Beyma is overdamped for this application (big magnet). You actually need a cheaper woofer with a small magnet.

Try to find a woofer with similar specifications to the Goldwood 1858, and you will be fine: Fs about 30, Qts about 1.1, Vas about 18.5 cu ft (524 liters)