Synergy Horns-Dayton and PRV..... - AVS Forum
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post #1 of 129 Old 10-27-2013, 04:13 PM - Thread Starter
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Sometime last year I became totally enamored by the Synergy Horn concept after several "a-ha" moments about how Tom Danley's other inventions work (Paraline, and Tapped Horn.) My S.O. (the bestest wife in the whole wide world) gave me permission to build a set of three for the LCR of our home theater. After many...many prototypes, rebuilds, back-tracks and a few choice words they are mostly done. I have Tom's permission to post details of my design, as it's his idea and he has it very well covered by patents.

First...for those that haven't heard a well designed DIY Synergy Horn, or the real deal. Find some. Now. They really are that special. I have a degree in Electrical Engineering and have designed audio equipment professionally on/off for over 20 years. They image better than any other speaker, and there is a precision and clarity that some of the crazy high end magnesium/beryllium/unobtanium based speakers can't match.

So, without further ado here are the basics for each speaker:

4 Dayton Classic 8" woofers, 295-310
4 Dayton Designer Series 3" woofers, 295-422
1 PRV Audio D290Py-B, 294-2833

22.5" Cube
60x60 Coverage Area
45Hz to 18kHz +/-3dB (ish)...more on that later.

I'll be posting the photo's I took during the build and my drawings...but it's going to take some time to put together all the info...so patience is appreciated. Questions are welcome at any time.

Scott


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post #2 of 129 Old 10-27-2013, 04:15 PM - Thread Starter
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Next up are some frequency response plots. I designed the speaker using SoundEasy V18, a Dayton Microphone and a custom jig I designed. SoundEasy is one of the best values...but also one of the quirkiest pieces of software I've ever used.

The on/off axis plots were measured with a real speaker in slightly different conditions than were used to measure the individual drivers for crossover development. I believe I might have some early reflections from a compost pile, trash can and garage door creeping in the on-off axis plots (taken at 0-10-20-30-45 degrees) which I didn't have for the measurements used for crossovers. Those were taken in a very large wide open band hall.

Scott


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post #3 of 129 Old 10-27-2013, 04:25 PM
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Very impressive!

JBL Pro Cinema
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post #4 of 129 Old 10-27-2013, 04:32 PM
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Wow great work. Thanks for sharing.

I've been pining for sound easy. Can't quite bring myself to spend the $250 when I'm getting by on what I have. Eventually ill drop the coin and wish I had years ago.
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post #5 of 129 Old 10-27-2013, 06:18 PM
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Lookin' good, Scott. Can't wait to see the schematics. How loud will they go before significantly distorting or compressing?

John
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post #6 of 129 Old 10-27-2013, 07:43 PM
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nice work. i look forward to your thread.

what advantage is there of something like this as compared with a horn loaded coaxial design?

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post #7 of 129 Old 10-28-2013, 02:48 AM
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Quote:
Originally Posted by johnbomb View Post

Lookin' good, Scott. Can't wait to see the schematics. How loud will they go before significantly distorting or compressing?

John

+1

What's the sensitivity?
How do you like the PRV Audio compression driver? Looks pretty smooth if crossed high enough.

Impressive build.

Cheers
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post #8 of 129 Old 10-28-2013, 04:15 AM - Thread Starter
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Quote:
Originally Posted by johnbomb View Post

Lookin' good, Scott. Can't wait to see the schematics. How loud will they go before significantly distorting or compressing?

John

Don't have measurements on that yet. Again, SoundEasy performs SPL measurements without absolute SPL. It doesn't have an absolute reference for voltage and can't do it. I have an old XP machine with Praxis that one of these days I'll fire up...it can do absolute SPL.

Subjectively? In a 20'x22' room a pair of them on 350W RMS will send you running from the room...with the amp clip indicators coming on long before any audible signs of distress from the speakers. Total output is not a problem.

Scott
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post #9 of 129 Old 10-28-2013, 04:20 AM - Thread Starter
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+1

What's the sensitivity?
How do you like the PRV Audio compression driver? Looks pretty smooth if crossed high enough.

Impressive build.

Cheers

I believe sensitivity is in the ~90dB/2.83V range. I have to pad down the PRV tweeter by 17dB or more at some frequencies to get the sensitivity to match. The PRV is a great driver with an amazing value proposition. I thought about the BMS drivers Danley actually uses, but these are a little over 1/3 of the cost. I almost got all 3 for what one BMS driver costs. Here is a plot with the raw vs. crossover tweeter response.

I actually want to cross it over a bit lower and see if I can't get better time/phase response out of the speaker.

Scott

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post #10 of 129 Old 10-28-2013, 05:12 AM - Thread Starter
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One of the bigger difficulties for starting a project like this is figuring out how to build the speaker. I had a few rules I set out for myself:

1. Do something where the back cup design for the midrange speaker is relatively easy to implement. I had a version where I was turning 6" burial grade conduit on my lathe. Not cool. Pain in the rear really. Many different closed back speakers will work, but a lot of them are relatively large (5" diameter plus) making placement near the tweeter a bit more challenging.

2. All drivers needed to be nearly vertical. The suspensions of a lot of home drivers will take a set over time if stored horizontal...I've seen it way too often. Since I'm using relatively inexpensive drivers I wanted to avoid this since I don't plan on building myself new speakers every 5 years or so.

3. The outside size limit was set by what my S.O. is willing to live with...and frankly they are pushing the boundary.

4. The enclosure needed to have access ports on the sides and back so that I could get to the internal wiring and drivers. I tried a version where I bolted the horn into a box...but I couldn't ever get the box braced very stiffly.

So...that said I decided that all drivers would be mounted on the two vertical side walls of the horn...and that those walls would run from top to bottom aiding with the bracing.

When building one of these horns the important thing to realize is that you're building a compound mitered box. My favorite is at: http://www.pdxtex.com/canoe/compound.htm

You could do all of the calculations by spreadsheet and there are plenty available for download. The above calculator is handy because it assumes you'll be using a table saw and tries to make sure you can run every piece flat on the saw. (You might have to flip something over....)

I've attached the drawings I used as a guide. There is one that I'll post more detail, and that is the one I used to create a template to mark driver mounting holes, entry ports, surround clearance routing...etc.

One very important thing to note about doing something like this without having the aid of a CNC router to machine all your parts.

Tolerance errors stack up...work slowly, carefully and don't panic. Each speaker will end up slightly different. Work to fit the parts to the project, not build all the parts and hope they go together. This is something I learned when building fine furniture. My three speakers vary by up to 1/16" of an inch in some dimensions.

Scott

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post #11 of 129 Old 10-28-2013, 06:44 AM
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So what advantages do you hope to gain with this Synergy design versus a more traditional waveguide or horn design? Better imaging? Better dynamics, more spl, or increased soundstage?
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post #12 of 129 Old 10-28-2013, 07:12 AM
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Not to speak for SpeakerScott, but I built one of these a while back (well, my experienced woodworking friend built the cab to my specs). It was a Danley SH-50 clone.

The main advantages are directivity (of course a waveguide also has this) and single point source. You can literally put your head inside the speaker and cannot tell where each frequency is coming from. Sounds like 1 driver is producing all the frequencies.

The making of 1 of these is quite involved for the woodworker. In the end I only made 1 and decided after paying my friend it was more cost effective to go with a WTW arrangement where I could make the cabs myself.

It also wouldn't make one of these passive. I have seen the crossover for the SH-50 and it is quite involved and expensive.

Hope this helps,
Moto
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post #13 of 129 Old 10-28-2013, 07:48 AM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post

nice work. i look forward to your thread.

what advantage is there of something like this as compared with a horn loaded coaxial design?

I think the main advantages are:

Improved directivity lower in frequency.
Improved vertical directivity if the coaxial design horn is size is limited.
Improved time domain performance.
Reduced diffraction/reflections for coaxial horn lenses.

Scott
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post #14 of 129 Old 10-28-2013, 07:55 AM - Thread Starter
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So what advantages do you hope to gain with this Synergy design versus a more traditional waveguide or horn design? Better imaging? Better dynamics, more spl, or increased soundstage?

So with the Synergy you guarantee that the sound sources are from the same virtual point, something sized roughly about a tennis or softball within the throat of the speaker. As previously mentioned they really do sound the same from 20 feet away as they do with your head nearly in the horn...just louder.

Any time you have non-coincident horns there is only one listening position where they sum correctly. In addition they can be time aligned (mine aren't but are very close...again more crossover adjustments needed.) at any position within their coverage angle. As a result imaging is unlike anything I've ever experienced...the pin-point accuracy of headphones without the "in your head" experience. All the advantages of conventional horn designs in terms of dynamics/spl are about the same.

Scott
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post #15 of 129 Old 10-28-2013, 07:59 AM
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Quote:
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So what advantages do you hope to gain with this Synergy design versus a more traditional waveguide or horn design? Better imaging? Better dynamics, more spl, or increased soundstage?

Better imaging, 100% cohesive phase, incredible sound stage, as point source as you can get. Rediculously good sounding.

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Originally Posted by MX48 View Post

Not to speak for SpeakerScott, but I built one of these a while back (well, my experienced woodworking friend built the cab to my specs). It was a Danley SH-50 clone.

The main advantages are directivity (of course a waveguide also has this) and single point source. You can literally put your head inside the speaker and cannot tell where each frequency is coming from. Sounds like 1 driver is producing all the frequencies.

The making of 1 of these is quite involved for the woodworker. In the end I only made 1 and decided after paying my friend it was more cost effective to go with a WTW arrangement where I could make the cabs myself.

It also wouldn't make one of these passive. I have seen the crossover for the SH-50 and it is quite involved and expensive.

Hope this helps,
Moto

I stick my head in the sm60f's all the time smile.gif What is even cooler is with proper toe in standing a few feet in front of them dead center and not having a clue where the speakers are with your eyes closed. Incredible soundstage, even when you are almost dead in between them I can put my nose on the theater screen which they are only a foot behind and not have a clue the speakers are dead to my left and right, all the instruments still sounds like they are right where they are supposed to be.

as far as the XO, yea, it is serious:


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post #16 of 129 Old 10-28-2013, 08:05 AM
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Hey Scott!! Great build man, I would love to try some synergies myself but two problems, my woodworking skills aren't quite that advanced, and I already have some sm60f's that make me smile every time I listen to them biggrin.gif

My big question for you is did you bake that little rise from 300hz down to 100hz in to your XO or is that just the native response of your design? My guess is it works quite well to your favor once in room to have a nice midrange "bloom" as I guess the "audiophiles" call it biggrin.gif Major Kudos man! I love seeing new members of the synergy horn club and even cooler when they are DIYers!

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post #17 of 129 Old 10-28-2013, 10:23 AM
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ah! good pic beast. so a few of those holes aren't woofer loaded, but are "ports".

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post #18 of 129 Old 10-28-2013, 02:49 PM
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the entry holes also probably serve as bandpass ports and as such create 90 degrees of phase shift and second order low pass filtering. this is something that i was just looking at for beast's setup, but i hadn't put it all together. interestingly, this is not mentioned in the danley patent, but he does mention crossover alignment (which may have similar phase shift as the acoustic low pass) and that there is something that requires "experimentation" to get right (maybe the extra 90 degrees not in the electronic filter calculation :-) ). with 90 degrees of phase shift, the drivers located at 1/4 distances, would be delayed exactly the right amount back to the cd at the throat/apex of the horn.

i couldn't figure out what is different from the heinz horn.

has anybody measured distortion on these things?

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post #19 of 129 Old 10-28-2013, 03:28 PM
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SpeakerScott
Love these ... just very cool, thanks for sharing.

What Tom Danley has hit on here is remarkable. I really have wanted to experience the Synergy approach myself, ever since I saw his designs. I've always wanted to mix a live event thru a Synergy rig, I've yet to get the opportunity. However, I did get the opportunity to spend a day with AVS'er/DIYSoundGroup'er bwaslo, and hear for myself his incredible DIY Co-Synes ... which is his interpretation of TD's amazing idea.

Well these things have a unique characteristics ... and imaging capability that didn't disappoint. Sitting directly in front of the either the right or left speaker (in a two-channel, L-R setup), a nice center image was maintained in a quite modest, non-dedicated room (even way off the center line). The design has tons of potential IMO. bwaslo spent next to nothing on driver cost/parts, a decent compression HF, and cheapo mids and woofs.

Seriously, with a $50 HF driver, $2, 2" mids, and woofers that were under $10 apiece, he achieved something extraordinary. So yeah, the Synergy design approach is remarkable. What I experienced was great results regardless of cost. However, when one factors expense into the equation ... the result is truly astronomical.

About the sound;
It possessed a naturalness and ease that doesn't typically emanate from a loudspeaker. The coherency and smoothness was very nice. It's like that one inexplicable experience, we've all had, that initally pulls you into the hobby ... that you spend a lifetime trying to re-create .. but here, with these, you have access to that anytime you want it. Natural Sound, not like a speaker. Those were my thoughts during my 2.5 hour trip driving home that afternoon.

---

The theoretical benefits of pattern control/controlled directivity realized down reaching toward the Shroeder freq, with low distortion techniques combining to radiate as a phase coherent point source.

So the image throw is one whereby there's just one coherent controlled lobe, and if you aim it at the opposite side seat, you can utilize time/intensity trading to cover a nice wide listening area. Also, what reflected energy does re-encounter the listening, it possesses the same level of coherence. With such pattern control, efforts to tame early reflected energy to achieve an adequate ITD gap, may not be as necessary as with other less controlled throw designs.

In other words, you get more direct sound, less reverberant smear. Other non-controlled designs are fine, but the lateral energy must be dealt with. As we've learned, if you absorb, you must absorb broadband. Do-able, but a nicely controlled throw is a elegant alternative.

LTD, you're right, the distortion lowering tricks are cool too. Using multiple small cones, the break up is pushed up well damped. The bandpass approach is an acoustic filter, lowering harmonic distortions, ...and the more offensive/higher order products are lessened the most. Certainly a win-win scenario. The acoustic low pass/distortion filtering has got to be a key factor in the naturalness I heard, lowering out of band energy etc.

The time/intensity trading contributed to a nice listening session, despite me sitting in front of the left main.

I'm sure the key elements of the driver chambers sizes, 1/4 wave interactions (throat and chambers), the ports and the port tunings, that would all be quite a juggling act of tradeoffs. All the while going after all the reduction possible of out of band output, filtering as much THD as you can. Fascinating ... beyond me.

SpeakerScott, again thanks for sharing, enjoy those bad boys ...

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post #20 of 129 Old 10-28-2013, 03:45 PM - Thread Starter
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Quote:
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Hey Scott!! Great build man, I would love to try some synergies myself but two problems, my woodworking skills aren't quite that advanced, and I already have some sm60f's that make me smile every time I listen to them biggrin.gif

My big question for you is did you bake that little rise from 300hz down to 100hz in to your XO or is that just the native response of your design? My guess is it works quite well to your favor once in room to have a nice midrange "bloom" as I guess the "audiophiles" call it biggrin.gif Major Kudos man! I love seeing new members of the synergy horn club and even cooler when they are DIYers!

I don't believe that rise to be real, or if it is real, not quiet that big. Long story short, but I was having a tough time getting SoundEasy to save the data during the band hall measurements. It's a tricky program. I believe the outdoor measurements comparing 0-10-20-30-45 are more real, except for the dip...that looks like a cancellation to me from a reflection off of something nearby.

Scott
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post #21 of 129 Old 10-28-2013, 04:09 PM - Thread Starter
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Quote:
Originally Posted by FOH View Post

SpeakerScott

About the sound;
It possessed a naturalness and ease that doesn't typically emanate from a loudspeaker. The coherency and smoothness was very nice. It's like that one inexplicable experience, we've all had, that initally pulls you into the hobby ... that you spend a lifetime trying to re-create .. but here, with these, you have access to that anytime you want it. Natural Sound, not like a speaker. Those were my thoughts during my 2.5 hour trip driving home that afternoon.


SpeakerScott, again thanks for sharing, enjoy those bad boys ...

You're welcome. Still have more stuff to go. Most of what I learned was construction related. Still not 100% sure I have it all right to be a true Synergy, I know Tom has more tricks up his sleeve than I can imagine...but I learned a few things along the way that may or may not be obvious. So I thought I'd put them out there.

Scott
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post #22 of 129 Old 10-28-2013, 04:46 PM
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Outstanding results. Thanks for sharing.
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post #23 of 129 Old 10-28-2013, 08:40 PM
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Awesome.

Never heard of PRV before, interesting.

Seems like this could become the Synergy kit that Tom never has time for, which could be much more doable with CNC'd box parts from Erich.
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...as far as the XO, yea, it is serious:


I'll say, I count 12 inductors!

Noah
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post #24 of 129 Old 10-29-2013, 05:01 AM
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Um....YES! Awesome work Scott, they look great and I'm sure they're great to listen to as well. I REALLY need to hear something like this in person soon.

Maybe that trip down to NC to visit Beast will come sooner than expected? biggrin.gif
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post #25 of 129 Old 10-29-2013, 05:27 AM
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So just out of curiosity, can the sound quality be improved by using higher quality compression drivers?

Which drivers are used in the Danley's? Are there any kits available for the actual horns? Or is the only way to get one of these horns to DIY or purchase one of Danley's completed speakers?
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post #26 of 129 Old 10-29-2013, 06:04 AM - Thread Starter
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One of the things I see folks struggling with is how to place the holes for the entry ports...and figure out the size/shape of the pieces for the compound mitered box.

Hopefully this set of drawings helps simplify it.

This doesn't get into 1/4 wavelength spacing...it doesn't get into cutoff or flare-rate...it just makes sure the holes end up where you want them and don't hit the side of the box.

So the coverage angle sets the initial angles...in my case 60x60...but the method works for any desired angle. The tweeter size sets the throat dimension which is where you need to start. In my case I'm using a 1" compression driver so I wanted a 1"x1" throat for the horn. I've seen that Danley's speakers don't smooth out the throat entry, but I keep reading that the entry is critical for hi-fi. I figured out a relatively easy way to get it smoothed and I'll go into that later.

The first drawing is the completed placement of drivers, drawn to scale, and port holes...but it's complicated. I've got a bunch of other dimensions in there that I was using as an aid during construction.

The second drawing shows the lines of where the inside of the horn would fall, the outside if the horn if it were butt jointed and the sides didn't extend...and the outside line of the pieces of the horn that are butt jointed.

One thing to remember with this compound miter...the outsides are smaller than the inside for the cut pieces...you have to angle them back as the pieces rotate out. It's tough to explain, but you'll see it if you cut some test pieces.

Which brings me to another very important point.

For all that is good and holy, cut some test pieces. Don't be afraid. Cut lots....figure out how this goes together on smaller cheap scrap. You'll save yourself a lot of trouble.

Scott
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post #27 of 129 Old 10-29-2013, 06:14 AM
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SpeakerScott, did/are you developing a passive crossover for these or is it strictly active?
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post #28 of 129 Old 10-29-2013, 04:41 PM - Thread Starter
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Quote:
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SpeakerScott, did/are you developing a passive crossover for these or is it strictly active?

It is a passive crossover, currently. I'll post my crossover when I get to it...but it may/may not be the final version. Still looking at ways to get a better time/frequency domain response.

I may do an active crossover but it's on the back burner due to cost. (I have a 12 channel amp...but I'd have to buy 3 mini-dsp boards....
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post #29 of 129 Old 10-29-2013, 04:44 PM - Thread Starter
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Originally Posted by Martycool007 View Post

So just out of curiosity, can the sound quality be improved by using higher quality compression drivers?

Which drivers are used in the Danley's? Are there any kits available for the actual horns? Or is the only way to get one of these horns to DIY or purchase one of Danley's completed speakers?

I believe BMS4550 for most of Danley's speakers. There are no kits licensed by Danley. Tom wants to do a home/hi-fi/audiophile version and has said so publicly several times. But that's not their primary business....and so it'll have to wait. Right now the only way to get them is to DIY or buy the real deal.

As far as improving the sound quality? I tried the Dayton polyimide compression tweeters and the PRV. The PRV was the clearly better driver. Could it get better? Maybe...but you'd probably be running up against a pretty steep price/performance curve. You'd have to spend a lot more to get not that much better performance. It's pretty dang good as it is.

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post #30 of 129 Old 10-29-2013, 05:37 PM - Thread Starter
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So next up in the build is how to repeatably drill all the stinking mounting holes. I wanted to use threaded inserts to ease driver replacement if ever necessary. I ordered a couple extra mids and woofers for myself in case one ever went bad. (One did...but in a crazy way, totally my fault...story to be told later.)

There will be hundreds of holes...between the access panels, driver mounting panels...etc. Have a drill press, it will speed things up greatly. It could be done by hand...very slowly and carefully...but it could be done. Also, please use a brad point bit or a forstner bit for drilling...preventing bits from wandering. Much more precise.

I made myself a marking template. I used 1/4" thick MDF that I laser cut using an exported DXF. (I have access to a laser cutter at work.) However, with a lot of careful measuring you could hand measure and mark it...and drill the guide.

I cut 1/4" holes and used something called a transfer punch to transfer them to the piece that would be used in the horn. It only took a couple of minutes to transfer all the drill locations to the work pieces where it would probably take you 20 or more each piece to measure every one. So totally worth the time.

You can also see I marked the location of the tweeter entry and the center line of the board.

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Dayton Audio Ds90 8 3 Designer Series Extended Range Speaker , Dayton Audio Dc200 8 8 Classic Woofer , Prv Audio D290py B 1 Polyimide Horn Compression Driver 8 Ohm 2 3 Bolt
Gear in this thread - Dc200 by PriceGrabber.com

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