New DIY Mid High (90deg) - AKA PM90

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Re: New DIY Mid High

That is one of my builds. There is a full set of measurements at my website in the link below. Of note is that once you apply a high pass filter the slight rise near vent tuning disappears and the box has a gradually sloping response from above 125Hz down to the effective vent tuning near 25Hz. I have found that this results in a relatively flat overall bass response once placed into a large club type room and still has good extension outdoors. However the sound of a system with extended response to the 25Hz range versus the typical system with a rising response and which effectively only extends to 35-40Hz is quite different. I it is easy enough to get more of a typical punchy sound by more aggressively filtering the bass below 40-50Hz with DSP. The reverse is not a good idea with cabinets without such natural extension. Or the sound can be made more typical sounding naturally by greatly reducing the cabinet size and tuning in the 35Hz range. In my experience the 21sw152 is one of the better engineered, well behaved, rugged and dynamic bass drivers on the market. A large part of how it will sound depends on what you do with it.
 
Re: New DIY Mid High

That is one of my builds. There is a full set of measurements at my website in the link below. Of note is that once you apply a high pass filter the slight rise near vent tuning disappears and the box has a gradually sloping response from above 125Hz down to the effective vent tuning near 25Hz. I have found that this results in a relatively flat overall bass response once placed into a large club type room and still has good extension outdoors. However the sound of a system with extended response to the 25Hz range versus the typical system with a rising response and which effectively only extends to 35-40Hz is quite different. I it is easy enough to get more of a typical punchy sound by more aggressively filtering the bass below 40-50Hz with DSP. The reverse is not a good idea with cabinets without such natural extension. Or the sound can be made more typical sounding naturally by greatly reducing the cabinet size and tuning in the 35Hz range. In my experience the 21sw152 is one of the better engineered, well behaved, rugged and dynamic bass drivers on the market. A large part of how it will sound depends on what you do with it.

Hi Josh,

Great website!

FWIW below are a couple of different alignments for the 21SW152. The white traces are in 280L box tuned at 25,30,35 & 40Hz. The red is what B&C suggests - 190L @ 33Hz. At the 25Hz tuning you have ended up with there is only a small ripple, the problem really starts when its tuned above 30Hz, which is what I expect Marjan heard.

Did you ever do a waterfall plot of the 21SW152 ... I would also love to see some waterfall plots and impulse response of some more tapped horns.

(I selected my best guess for QL, Qa & Qp to match your design, a Vc temp rise of 30 degrees and 2000 watts input)
 

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Re: New DIY Mid High

Pete,
It is all there...Click on systems tab. Then you click on the name of any system. For the 21sw152 driver there is sealed, dual opposed sealed, ported, Othorn tapped horn) then click on the measurements link. From there you can click on comparable charts, multi series charts, extended charts or static graphs. Waterfall, group delay and spectrogram charts are shown under static charts for each system. Clarity on what and how the measurements are taken and with what equipment are available under the know how tab. It explains a lot. Sorry for the thread OT.
 
Re: New DIY Mid High

Pete,
It is all there...Click on systems tab. Then you click on the name of any system. For the 21sw152 driver there is sealed, dual opposed sealed, ported, Othorn tapped horn) then click on the measurements link. From there you can click on comparable charts, multi series charts, extended charts or static graphs. Waterfall, group delay and spectrogram charts are shown under static charts for each system. Clarity on what and how the measurements are taken and with what equipment are available under the know how tab. It explains a lot. Sorry for the thread OT.


Fantastic, I didn't look hard enough - love your work :)~:)~:smile:

Thats the first time I have seen the impulse response of a tapped horn ... about what I expected.

Thx

Peter
 
Re: New DIY Mid High

Hey Peter,

Great work on the Mid-High cabinet and thanks for posting it here.

What are your thoughts on arraying this cabinet? Since you mention that the pattern behaves itself, I assume they would array well.

Also, have you thought about making the plans available or for purchase? There seems to be a shortage of really capable cabinets in this size range; somewhere between a small line array and a speaker on a stick. If your cabinet can array well and if the engineering and certification to fly it could be tackled, it could make a really good choice for mid sized providers.

Thanks
Simon
 
Re: New DIY Mid High

Hello

To Josh - years ago - maybe 2002 - I visited Genelec - they are manufacturing studio monitors here in Finland. They showed me innards of a speaker cabinet - propably http://www.genelec.fi/tuotteet/vanhat-mallit/1031a/ - and I noticed they had damping material folded in a way it blocked free air travel between woofer and ports - I asked about it and they said it is okay. Surely they must have tested it. Any clue ???
 
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Re: New DIY Mid High

Hello

To Josh - years ago - maybe 2002 - I visited Genelec - they are manufacturing studio monitors here in Finland. They sowed me innards of a speaker cabinet - propably http://www.genelec.fi/tuotteet/vanhat-mallit/1031a/ - and I noticed they had damping material folded in a way it blocked free air travel between woofer and ports - I asked about it and they said it is okay. Surely they must have tested it. Any clue ???

It will have an impact on Qa (dampening material losses) and Qp (port losses). Have a look at the advanced settings in WinISD Pro and you can see the effect …also note the effect of changing Ql.
 

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Re: New DIY Mid High

Timo, Peter has already answered well. Additionally it is worth noting that the most effective place to put material in a cabinet in order to dampen standing waves with the least amount of material is towards the center and not lining the walls as many do.
 
Re: New DIY Mid High

Hey Peter,

Great work on the Mid-High cabinet and thanks for posting it here.

What are your thoughts on arraying this cabinet? Since you mention that the pattern behaves itself, I assume they would array well.

Also, have you thought about making the plans available or for purchase? There seems to be a shortage of really capable cabinets in this size range; somewhere between a small line array and a speaker on a stick. If your cabinet can array well and if the engineering and certification to fly it could be tackled, it could make a really good choice for mid sized providers.

Thanks
Simon

Hi Simon,

I don't think this version would array particularly well because of the 90 x 50 degree HF horn .... however I made the box just wide to accommodate one of these http://www.eighteensound.it/PRODUCTS/Products/CatID/5/ProdID=180#.VKyQB2kbrq4 just in case my mid horn idea worked and I wanted to make a version that could be arrayed.

You are exactly corrected where I targeted the design. I wanted a speaker on a stick that had the output of something like and EAW KF850, or as you put it, fill the gap between a "normal" speaker on a stick and a small line array, perhaps even replace a small line array especially where there are no options to fly an array.

I wanted a small but manageable box that one or two people could lift onto a stand, the best sound quality and as much SPL I could squeeze into the smallest box possible. It was designed to be always used with a sub, and for the sub to be in reasonably close proximity so you could get away with a 100Hz crossover. When combined with a double 18 or 21 you would have a powerful rig that would easily fit into a reasonable size van that could be set up by one or two people. I was hoping it could used in situations that previously required a small truck and two or more people, hence providing an economic advantage $$$$ .

I was also hoping that it would have good pattern control, especially low mid vertical control so that the box could be flown and used for theatre applications. There is often a problem with lapel mics in the low mids where the FOH box spills 150-500 Hz back onto the stage.

The plan is also to make it flyable ... In terms of engineering its not a problem, I have a degree in mechanical engineering ... and also electrical engineering.

I have no plans to sell any design or plans, but when I have time I would be happy to put all details up on this site. At this stage the design is just a prototype sketched out on scrap bits of paper, so I don't have any drawings yet ... and I'm sure the next version will have a few modifications.

What I was hoping for at this stage was some help, suggestions and constructive criticism ... which is exactly what has happened- thanks to all so far
 
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Re: New DIY Mid High

Hey Peter,

That EighteenSound horn looks a lot like the one used in the Seeburg K24, which has a very similar layout to your cabinet and is meant to array fairly well. Some friends have given me mixed reviews about the sound quality, but that's not particularity scientific and probably has more to do with the mix, then the cabinet. The K24 doesn't use the coax driver that you use which will probably make a big difference as well.

The fly structure of the K24 is one of the smartest setups I've seen recently, with all hardware integrated and ball lock pins clipping it all together. The only thing needed externally is a fly frame.

Reading back through this thread, are you currently driving the cabinet three way? Would it be possible to develop an internal passive network (Too Tall is out there somewhere??) and use it in combination with FIR filters on a single amp channel? Or would the passive crossover interfere with the FIR processing? Just curious if there is a simpler amp/dsp setup that is more practical for everyday use, aka. throw and go combat audio.

Thanks again for the work.

Simon
 

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Re: New DIY Mid High

Hey Peter,

That EighteenSound horn looks a lot like the one used in the Seeburg K24, which has a very similar layout to your cabinet and is meant to array fairly well. Some friends have given me mixed reviews about the sound quality, but that's not particularity scientific and probably has more to do with the mix, then the cabinet. The K24 doesn't use the coax driver that you use which will probably make a big difference as well.

The fly structure of the K24 is one of the smartest setups I've seen recently, with all hardware integrated and ball lock pins clipping it all together. The only thing needed externally is a fly frame.

Reading back through this thread, are you currently driving the cabinet three way? Would it be possible to develop an internal passive network (Too Tall is out there somewhere??) and use it in combination with FIR filters on a single amp channel? Or would the passive crossover interfere with the FIR processing? Just curious if there is a simpler amp/dsp setup that is more practical for everyday use, aka. throw and go combat audio.

Thanks again for the work.

Simon

The difference between these two designs is that the DIY design has a mid-horn that is about 2ft (600mm) long. The K24 has a bit of horn or cavity that the 12s fire into that will produce a smooth peak around 400Hz.

As a guess, and after a bit modelling in Hornresp, they will have similar output above 400Hz but from 100 to 300 Hz my design should have about 5 dB more output.

The BMS4594 compression driver also allows the crossover to be in the 650 – 800 Hz range and it has more output than a normal compression driver. This means the 12s can operate in their piston range and the dipole arrangement does not to cause any issues off axis. The only negative is the vertical pattern of the HF horn gets a bit wide down low. There is also a price $ for components of this quality – they are not cheap.

When I looked at Seeburg’s DSP settings for the K24, it nominally crosses at 1000Hz, but it looks like they also have a 700Hz setting, I assume for improved sound quality at the expense of maximum SPL. http://www.seeburg.net/LoudspeakerLibrary_HDLM8_10_13.pdf

I also have to say how impressed I am with the 4594HE – the sound quality is stunning, when listening to a good recording the stereo image is so good that you don’t hear the speakers, the sound comes from imaginary instruments and singers behind the speaker, if that make sense. It sounds like you a listen to a set of big studio monitors.

Regarding the passive crossover – it may be a bit tricky because the horn needs a reasonable amount of delay to time align it with the 12’s. Certainly you could use BMS’s crossover for the 4594 and make the box 2-way. That way you could use it with a 4 channel DSP amp.

For “throw and go” applications I think it would be easier to build a version to take a Powersoft amp/DSP module.

BTW thanks for the Pdf, I had never heard of Seeburg, they have some interesting speakers.

 
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Re: New DIY Mid High

FWIW: A couple of manufacturers have done a speaker with a passive XO that you can use with single channel FIR-processing. Sounds pretty good on those I've heard.

FWIW I used one of these http://aplaudio.com/conc2/apl1/ to measure and calculate an FIR correction curve. Then measured the resultant with Systune and copied the appropriate (not all) corrections into the LM26 like this https://www.youtube.com/watch?v=-LLYkGj7Zbk

I also did a flat response with Systune for comparison.

Having said that the box does not need much correction to produce excellent results :)~:)~:smile:
 
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Re: New DIY Mid High

Hey Peter,

Seeburg is about an hour East of my old home in Stuttgart, Germany. They and another local company, TW Audio, had significant presence in the central European market and are both well respected. TW Audio is a bit more mainstream in their products, nothing really interesting or odd, but very good stuff and very well thought out. Seeburg is a bit more creative and as you noted, has some interesting products. Their mini line array cabinet is really hard to beat for Voice reproduction in reverberant spaces. I often rented one of their large horn loaded systems for outdoor concerts and always liked how smooth they were.

That being said, the TW Audio T24 is my absolute favorite cabinet so far. It's sound is incredibly coherent - the tonal balance doesn't change at all with distance, it just gets quieter. Two flown, one under the other, along with 4 of their double-15 subs a side is a hugely capable rig that fits easily in a 5x8 trailer. A few years ago I listened to them at ProLight and Sound in Frankfurt and thought they were doing a better job then even some of the high dollar line arrays.

For “throw and go” applications I think it would be easier to build a version to take a Powersoft amp/DSP module.

Have you worked with the Powersoft amp modules? They look really promising, but I haven't seen pricing yet. If it's anything like the rest of the Powersoft line, they are going to be pricey.

Ciao
Simon
 
Re: New DIY Mid High


The most interesting thing on this whole thread is this piece of software you posted. I have wondered for years when and if some form of Time-Frequency analysis would get bundled into a end-user software package which actually proved useful. I had never even heard of this company before.

I hope more people start using tools like this so we can finally break free from looking at just simple FFT'd responses and the tools like they have made gain wider industry acceptance.

Very cool. Thanks,
Mark