New DIY Mid High

May 8, 2011
897
37
28
Australia
#42
Re: New DIY Mid High

Something out of the ordinary has happened to lose a midrange with these settings.
They are rated to cross at 300hz, and I use them to that point regularly.
EAW use quite a lot of these drivers and I believe they cross them typically around 450Hz to 500Hz.

I spoke to Kenton the other day about this driver (or their variant) and he said their reliability has been excellent and they have had very few failures.

I guess I'm about to find out ...8)~:cool:~:cool:
 
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#43
Re: New DIY Mid High

We(my dayjob) have done a few installs with EAW speakers using these drivers, so far one failure in three years. My boss called EAW to order spares and they we're curious about the cause for that failure, I believe it was one of the first ones ever recorded. We replaced the diaphragm and have had no further issues.

Reliability and SQ is very good on these drivers.
 
May 8, 2011
897
37
28
Australia
#48
Re: New DIY Mid High

I would be interested in more information about this box as it becomes available. Thank you..
Here are some more details:-

HF Driver and Horn
The one thing that makes this box work is the BMS 4594. It allows the crossover to the low mid to be around 600 – 700Hz. The new HE version has a slightly flatter frequency response and uses shorting rings for lower distortion.

The BMS 4594 is coupled to one of RCF’s new HF950 horns. I suspect this is one of the best horn flares RCF have made. It’s used in their newTT2a and TT5a and has a cut of frequency of 400Hz.

Pattern Control

The size of the HF horn and the wavelengths involved allowed it to be mounted in the centre of the mid horn. By doing that, the MIDs are in a dipole configuration which controls the vertical pattern to around 40 – 50 degrees, maintaining good pattern control down to 200Hz. It performed exactly as predicted by the simulations I ran during the conceptual design stages. The only compromise is that the HF horn gets a bit wide between 800 – 1500Hz, although in practice it does not appear to be an issue.

Consider looking at some plots of your typical 15 and view the off axis vertical frequency response - this information is hard to find, but here are some examples below; in comparison this DIY box is excellent; the only boxes I know that will do marginally better are perhaps some of Danley’s large Synergy horns, but the compromise for achieving better pattern control is that the box needs to be significantly larger.

At or below the crossover frequency the width of the mid horn is such that its shape has less impact than its overall width on controlling horizontal directivity. Because both the MID and HF horns have the same width, the directivity transition between the two is very well matched. The horizontal pattern and off axis frequency response are as good as I have seen.

Mid Horn
The mid horn is an exponential horn with a compression ratio of about 3 to 1 and a length of about 600mm. As noted above, it’s ported at about 85Hz with ports venting into the mouth of the horn.

It uses 2 x RCF 12 inch neo’s, and once again I selected a very new and low distortion driver.

There are some slightly more powerful drivers that will produce a little more SPL; however they have larger magnets and are heaver. These drivers would have made the box close to 40Kgs which was more than I wanted ….. my prototypes are 34Kgs including paint and speaker grill.

I modelled every suitable driver I could find during my research in Hornresp. To get the box to go down to 100Hz and still maintain a reasonable size enclosure required the horn to be ported at around 85Hz. I would have preferred to use a pure horn and not to port the box, but without it, the box became too big.

The port also minimizes the cone excursion, which was matched to the selected driver and its power rating, thus maximizing the efficiency. Cone excursion should not be a problem above70 Hz.
The trick with this design is that the 12 inch is operating only in its piston range typically below approximately 700Hz. The volume between the cone and horn mouth acts as a low pass filter. Many designs using that use 12 inch mids required the mid to operate up to 1200 Hz or more, however, when using the lightest cone available it is generally not possible to get a 12 inch driver to go above 700Hz and operate as a piston. By operating the MID only in its piston range ensures low distortion and excellent sound quality.

Box Construction

The box is constructed with lightweight 17mm ply, but it has significant bracing and many of the internal surfaces are curved resulting in a lightweight ridge enclosure. There is also virtually no dead space within the box, as every part of the box forms either the horn flare or the speaker enclosure. This minimizes its size and weight. Even the pole mount is integrated into the enclosure to provide extra bracing between the base and centre speaker enclosure.

Listening Tests
Without a doubt this speaker exceeds the sonic performances of any speaker I have ever owned. It sounds better and measures better; its impulse response is as good as I have ever seen and there are very few speakers in the world that can reproduce a square wave both on and off axis (horizontal and vertical).

· EAW – KF730-UX8800, KF650z-UX8800, KF750-UX8800,DSA 250
· Nexo PS15
· RCF TT22a, TT2a
· Turbosound Flex, TMW115, TMW112
· Meyer UPA

Reference Material
http://www.rcf.it/en_US/products/precision-transducers/neodymium-low-frequency-transducers/mb12n351- RCF 12 inch
http://www.rcf.it/en_US/products/precision-transducers/horns/hf950- RCF Horn
http://www.jblpro.com/ProductAttachments/VP7315_64[1].pdf - see off axis frequency response
http://www.electrovoice.com/product.php?id=29 down load Pdf – see off axis frequencyresponse
http://www.renkus-heinz.com/upload/st-stx4-datasheet-1.pdf- similar concept
 
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May 8, 2011
897
37
28
Australia
#50
Re: New DIY Mid High

Have you done any comparisons with a EAW KF394?
It uses a similar Mid/HF driver, if not the same driver, as your design.

I've done a few gigs with that, it's a very good speaker.

No I haven’t heard the KF394, but I love how EAW appears to have put so much sound quality and horse power in such a small box. As far as I know it uses a 4594ND and a couple of these - http://www.eighteensound.it/PRODUCTS/Products/CatID/8/ProdID=28#.VJ30btY-ALA or something similar. It uses a passive crossover between the HF and VHF, but it’snot the same as the BMS crossover that I mention above. I have heard the QX594 which is similar is some ways http://eaw.com/portfolio_page/qx594i/- they sounds excellent and go extremely loud.

In comparison to the KF394 my DIY box is bigger and about 4Kgs heavier and should be noticeably louder.
I used it for the first time as infill for a small Christmas Carols show. It gave me a chance to see how loud they go and tweak the DSPsettings a little.

I have to say it’s one of the loudest boxes for its size I have ever come a cross. My aim was to build a speaker on a stick with SPL capabilities of an EAW KF850. I think I have come close. I used it with my double 18 - 3600 watt subs which are loaded with 2 x 18sound 18NLW9000 powered by a Powersoft K10. This DIY MID HI needs more LF than one of these double 18's, as a guess it probably needs 2 of your standard 2000 watt double 18” subs … there is a double 21” (2 x B&C 21SW152) on its way as a matching sub for this box
J.
 

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#51
Re: New DIY Mid High

Looks like you have made a pretty serious speaker. Do you take orders ;)

One really fun thing with speakers that sounds this good is trying to guess how loud it is before you look at your SPL meter. The lack of distortion in the speaker itself removes some of your reference points, so you're constantly 6-10 dB low in your guessing until you get used to it. Going back to another speaker, you start mixing at a lower volume because it sounds "too loud".

The first time I ran into that was when I took the SH-50s I owned along with some Labsubs to a gig. It didn't feel loud at all until I tried to talk to someone and had to scream to be heard. IME: That BMS-driver on a good horn with some nice DSP-settings is the only thing I've heard that can match the sound quality of a SH-50.
 

Ivan Beaver

Graduate Student
Jan 11, 2011
2,300
7
0
Atlanta GA area
#52
Re: New DIY Mid High

Looks like you have made a pretty serious speaker. Do you take orders ;)

One really fun thing with speakers that sounds this good is trying to guess how loud it is before you look at your SPL meter. The lack of distortion in the speaker itself removes some of your reference points, so you're constantly 6-10 dB low in your guessing until you get used to it. Going back to another speaker, you start mixing at a lower volume because it sounds "too loud".

The first time I ran into that was when I took the SH-50s I owned along with some Labsubs to a gig. It didn't feel loud at all until I tried to talk to someone and had to scream to be heard. IME: .
I have noticed the same thing.

What I have also noticed is that for some reason there seems to be a lot less "ear fatigue". Your ears don't seem to ring as much-even though in many cases it is actually louder SPL wise.

But even though it is so loud you can't talk-some people say "It's not loud enough" because they are looking for the distortion and they associate the distortion with SPL.

I have run across BEs who mix for a particular level of distortion-not just SPL. Give them a little it of distortion and they will back the level down.
 
May 8, 2011
897
37
28
Australia
#53
Re: New DIY Mid High

I have noticed the same thing.

What I have also noticed is that for some reason there seems to be a lot less "ear fatigue". Your ears don't seem to ring as much-even though in many cases it is actually louder SPL wise.

But even though it is so loud you can't talk-some people say "It's not loud enough" because they are looking for the distortion and they associate the distortion with SPL.

I have run across BEs who mix for a particular level of distortion-not just SPL. Give them a little it of distortion and they will back the level down.

That sounds familiar ... I had a small PA in a bar that mostly booked D grade grunge and thrash bands. They would always complain it was not loud enough so I more or less removed the compressor/ limiter and fitted a diode clipper so it would sound distorted before any damage was done. After that they were happy.

Out of curiosity – approximately where to you cross the HFdriver(s) in the SH96HO and J1?
 

Ivan Beaver

Graduate Student
Jan 11, 2011
2,300
7
0
Atlanta GA area
#54
Re: New DIY Mid High


Out of curiosity – approximately where to you cross the HFdriver(s) in the SH96HO and J1?
We don't use "normal" crossovers in our products.

Yes we use high and low pass filters-but they are at different freq (often overlapping), sometimes with different types of slopes and often some out of band eq.

This is done to get the best phase and amplitude response.

Of course the acoustical and electrical crossovers are different.

But as a "general" idea it is around 1500ish Hz(give or take), I don't recall off hand.

Often times we use multiple "crossovers" in a product. In one case there are actually 4 "crossovers" for the HF.

As with many things-there is no simple singular answer.
 
May 8, 2011
897
37
28
Australia
#55
Re: New DIY Mid High

We don't use "normal" crossovers in our products.

Yes we use high and low pass filters-but they are at different freq (often overlapping), sometimes with different types of slopes and often some out of band eq.

This is done to get the best phase and amplitude response.

Of course the acoustical and electrical crossovers are different.

But as a "general" idea it is around 1500ish Hz(give or take), I don't recall off hand.

Often times we use multiple "crossovers" in a product. In one case there are actually 4 "crossovers" for the HF.

As with many things-there is no simple singular answer.
I would expect you to be doing all of that - my curiosity was about the compression driver you are using in these particular boxes. Its capable in a large horn of operating down to about 300Hz; I was just wondering how far down you were taking it and how much work it was doing.

Thanks ....
 
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#56
Re: New DIY Mid High

Having heard the 21SW152 in a fairly large reflex box, i wasn't impressed at all with the performance. Yes it shifted lots of air but the sound was kinda undefined and it lacked definition. Perhaps if combined with an upper bass cabinet the result would be better. Crossed at 80Hz to a 15+2 top box it definitely lacked punch.
 
May 8, 2011
897
37
28
Australia
#57
Re: New DIY Mid High

Having heard the 21SW152 in a fairly large reflex box, i wasn't impressed at all with the performance. Yes it shifted lots of air but the sound was kinda undefined and it lacked definition. Perhaps if combined with an upper bass cabinet the result would be better. Crossed at 80Hz to a 15+2 top box it definitely lacked punch.
That’s the opposite of reports I have heard; people have describe the sound as having a lot of impact, like being hit in the chest with a hammer, however they have all been in relatively small boxes - around 190L per driver.

I think a lot of people are focused on LF extension and end up building designs that are under damped with a LF resonance peak. They sound exactly as you described.

I have always like the sound of slightly over damped designs using drivers with a Qt of about 0.3 like the 21SW152.

I believe Fulcrum use this driver (or similar) in theirUS221 and EAW in their SB2001, possibly Danley in their TH221 (?)

I guess I'm about to find out :)~:)~:smile:

 
Apr 27, 2012
30
1
8
#58
Re: New DIY Mid High

My experience with the 21sw152's has been the opposite of Marjan's. I've used them for around 4 or 5 years in a variety of cabinets. Often when people talk of one box being subjectively "tighter" or having more "punch" it relates to the lack of deep bass in the output of the system with a "tighter" sound or the presence of elevated levels of 2HD and 3HD. Subwoofers with lower extension sound slower because the low bass IS slower. As with most things it is best to listen or research and form your own opinions. Good luck.
 
Jan 11, 2011
931
0
0
Troy, NY
#59
Re: New DIY Mid High

My experience with the 21sw152's has been the opposite of Marjan's. I've used them for around 4 or 5 years in a variety of cabinets. Often when people talk of one box being subjectively "tighter" or having more "punch" it relates to the lack of deep bass in the output of the system with a "tighter" sound or the presence of elevated levels of 2HD and 3HD. Subwoofers with lower extension sound slower because the low bass IS slower. As with most things it is best to listen or research and form your own opinions. Good luck.
This makes sense from my experience. That, and my theory that most don't get the opportunity to LEARN how to manage actual sub bass frequencies. I did a walk in last night and of my many suggestions was setting up a proper aux fed sub system with appropriate eq and dynamic abilities to manage the subs separate from the top of the system. I had years of club experience and being able to adjust the 'feel' of the system by slight 'tilting' if the sub/mid hi balance, especially effective when the crowd density changes.
 
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May 8, 2011
897
37
28
Australia
#60
Re: New DIY Mid High

My experience with the 21sw152's has been the opposite of Marjan's. I've used them for around 4 or 5 years in a variety of cabinets. Often when people talk of one box being subjectively "tighter" or having more "punch" it relates to the lack of deep bass in the output of the system with a "tighter" sound or the presence of elevated levels of 2HD and 3HD. Subwoofers with lower extension sound slower because the low bass IS slower. As with most things it is best to listen or research and form your own opinions. Good luck.
I have found the same ..... the alignment used can also have a significant effect. Here is an example of what I was talking about above - both boxes using a 21SW152 and tuned to 33Hz - one box is 190L the other 380L. The green plot will sound good, the red will sound as Marjan described.
 

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