Hey Art, I'm in the process of building a pair of your SyntripPs to go with the Keystone subs I built. I have the primary horn completed and am currently refining the crossover points, eq and general tuning. I'm using the standard B&C 10cl51 mid drivers paired with an Eminence N314x compression driver. So far they are already sounding fantastic but I have a few minor issues to sort out still.
Firstly, I'm finding it a bit tricky to properly fill in the 800-950 crossover point between the mids and CD. The N314x mounted in this horn begins to roll off at about 1000Hz(-3db @ 910hz, -6db @ 850hz, -9db @800hz). Ive essentially had to overlap the crossover points slightly and use the natural rolloff of the CD in order to "fill in the gap". Is there any downside to this? Also curious about the minimum recommended crossover point for the CD driver of 800hz 12db BW. Am I correct in thinking that as long as my crossover point is above this it will be safe from mechanical damage? Obviously I wont be requiring the full output of the CD driver considering it is rated for 150AES/300 peak and outputs 110 db@1m/1w but I cant find anything on the web regarding what exactly the minimum crossover point means in regards to safely powering compression drivers. One other issue I'm having is that there seems to be substantial resonances directly behind the compression driver. The N314x has a flat backplate and there is under 1" between the CD and the back panel of the syntripp ( Only about 1/4" if you count the heat radiating fins) . Sound radiating off the back of the cd seems to get trapped between there and it is slightly audible out front on certain tracks. I feel like with the Celestion driver and its dome shaped back maybe doesn't have this same resonance problem. Do you have any recommendations in dealing with this? I do have a substantial amount of fiberglass insulation on the sides, bottom and back panel but there isn't much room for the insulation to "breath" behind the CD. Im thinking about renovatign the back panel to make more room between the CD and back panel by cutting out behind the driver and then just doubling up on the plywood for the back so that the insulation wont be so squished.......or maybe there is some other material that would work better than insulation to dampen these resonances? I am installing an Eminence top hat pole mount which will take up about the same amount of space as I would gain from carving up the back so the overall volume of the box shouldn't change much.
Also, Thank you so much for sharing your creations. Ive been having a blast building and refining the SyntripPs as well as the Keystones and I cant wait to show off the full sound system once its all competed!
Firstly, I'm finding it a bit tricky to properly fill in the 800-950 crossover point between the mids and CD. The N314x mounted in this horn begins to roll off at about 1000Hz(-3db @ 910hz, -6db @ 850hz, -9db @800hz). Ive essentially had to overlap the crossover points slightly and use the natural rolloff of the CD in order to "fill in the gap". Is there any downside to this? Also curious about the minimum recommended crossover point for the CD driver of 800hz 12db BW. Am I correct in thinking that as long as my crossover point is above this it will be safe from mechanical damage? Obviously I wont be requiring the full output of the CD driver considering it is rated for 150AES/300 peak and outputs 110 db@1m/1w but I cant find anything on the web regarding what exactly the minimum crossover point means in regards to safely powering compression drivers. One other issue I'm having is that there seems to be substantial resonances directly behind the compression driver. The N314x has a flat backplate and there is under 1" between the CD and the back panel of the syntripp ( Only about 1/4" if you count the heat radiating fins) . Sound radiating off the back of the cd seems to get trapped between there and it is slightly audible out front on certain tracks. I feel like with the Celestion driver and its dome shaped back maybe doesn't have this same resonance problem. Do you have any recommendations in dealing with this? I do have a substantial amount of fiberglass insulation on the sides, bottom and back panel but there isn't much room for the insulation to "breath" behind the CD. Im thinking about renovatign the back panel to make more room between the CD and back panel by cutting out behind the driver and then just doubling up on the plywood for the back so that the insulation wont be so squished.......or maybe there is some other material that would work better than insulation to dampen these resonances? I am installing an Eminence top hat pole mount which will take up about the same amount of space as I would gain from carving up the back so the overall volume of the box shouldn't change much.
Also, Thank you so much for sharing your creations. Ive been having a blast building and refining the SyntripPs as well as the Keystones and I cant wait to show off the full sound system once its all competed!
FinkNewton,
1) My initial crossover settings used a 800Hz BW24 on the 10", and a 950Hz LR24 on the HF driver, with a .4Ms delay. The N314x being around -6dB at 800Hz relative to the Celestion will either require a lower Xover (try BW24 900 Hz) or an EQ adjustment to flatten response.
You should also experiment with the HF polarity and delay, a gap could be due to either.
2)Good question- the horn the N314x is tested to reach the 150W (AES) rating loads the driver lower than the conical SynTripP horn, so excursion (and power) to reach same SPL would be greater on the SynTripP. My guestimate would be the N314x would take 150W peaks at 24BW as low as 800Hz before the diaphragm hits the phase plug, but not sure if it would make it with a 12dB slope.
3) The N314x on the SynTripP, or the Eminence horn it was tested on is not 110dB at 800 Hz, but should still be able to outrun the 2x10" without exceeding Xmech up to at least 125dB.
I'm guessing by the HF rolloff that the Eminence has close to a 1mm Diaphragm to Phase Plug Space (DPPS), but more recent JBL drivers have only .5mm, 6dB less!
Some discussion here:
Calculating excursion of a compression driver
4)Having never heard (or measured) any "substantial resonances" directly behind any compression driver I've ever tested, I have no recommendations. Post up response with no smoothing so we can see what you are hearing!
Art
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Appreciation Post
I want to extend my gratitude to Art and the community here. At long last I finally got my SynTripP's together (only took 6 months). It's been quite an adventure and I learned so much along the way. When I first discovered the SynTripP I was convinced I'd never have the skills to build it but here we are.
I only have a few hours of play time but I am already in love with the sound of these. I was initially nervous as I had never heard a multiple entry horn before and I didn't know what to expect. They surpassed all of my expectations and were worth every bit of work that went into them. I can't wait to pair these with my 4 keystones and let them sing.
I want to extend my gratitude to Art and the community here. At long last I finally got my SynTripP's together (only took 6 months). It's been quite an adventure and I learned so much along the way. When I first discovered the SynTripP I was convinced I'd never have the skills to build it but here we are.
I only have a few hours of play time but I am already in love with the sound of these. I was initially nervous as I had never heard a multiple entry horn before and I didn't know what to expect. They surpassed all of my expectations and were worth every bit of work that went into them. I can't wait to pair these with my 4 keystones and let them sing.
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Excellent work!
Looking forward to seeing some measurements, especially of the HF section.
Did you use the Eminence NX314T?
Are you planning to build the secondary expansion?
Art
Thanks Art!
Imgur: The magic of the Internet
Here is a link to the initial response curve with very limited eq and drivers not yet broke in. I plan to get some hours on them before I spend too much time tinkering with any more eq. If you have any resources on taking measurements I'd love to hear about them. I'm still very new to that world.
I ended up using the N314T-8. I was going to use the N314X but decided against it strictly due to the cost. Maybe some day I'll give them a try. I do plan on building the secondary horns as well but I think I'll wait until it gets warm out for that.
Imgur: The magic of the Internet
Here is a link to the initial response curve with very limited eq and drivers not yet broke in. I plan to get some hours on them before I spend too much time tinkering with any more eq. If you have any resources on taking measurements I'd love to hear about them. I'm still very new to that world.
I ended up using the N314T-8. I was going to use the N314X but decided against it strictly due to the cost. Maybe some day I'll give them a try. I do plan on building the secondary horns as well but I think I'll wait until it gets warm out for that.
Hey Art! I ended up taking a bit of material out from behind the compression driver which allowed me to add a bit more insulation to the back panel. I also added more insulation to the sides as well as broke in the mid drivers. Since making these changes the resonances I was hearing earlier on certain songs has completely dissapeared! I think it was likely that i just had insufficient insulation to tame the resonance coming off the mid drivers.
Also, the weather finally cooperated and I managed to get the Syntripp outside to a clearing to take a measurement of the n314x for you. Here is the frequency response taken 2m away with the syntripp 5 feet off the ground. My generator was only about 30 feet away and there is a river nearby so conditions were not ideal but I reckon its better than nothing. No eq applied. No smoothing. No secondary horn.
Also, the weather finally cooperated and I managed to get the Syntripp outside to a clearing to take a measurement of the n314x for you. Here is the frequency response taken 2m away with the syntripp 5 feet off the ground. My generator was only about 30 feet away and there is a river nearby so conditions were not ideal but I reckon its better than nothing. No eq applied. No smoothing. No secondary horn.
Glad to hear the mid problems gone.
Would like to compare the roll off below 500 Hz, could you post the response of the HF down to 60 Hz or so?
Thanks,
Art
I was sending the test tone directly from my sound card to the amp bypassing the crossover in the Driverack so I started the sweep at 500hz to be safe. I am new to testing and measuring speakers and I'm always worried I'm going to break a driver...... :S I have a Hypex NC252 amp coming this week to power the compression drivers so weather permitting I'd like to get the speakers out for more testing this weekend. Ill take a low powered measurement down to 60hz then! Cheers.
That is surprisingly even response for a conical horn over such a wide bandwidth, thanks for the test.
Are you planning to check the polar response?
Hi Art,
It’s been a long time since I visited here. Glad to see all the interest and so many successful builds of this speaker by others. Hope you are doing well.
I am really leaning towards speakers with passive crossovers. Have you made a passive XO design for the SynTripP yet?
Regards,
X
It’s been a long time since I visited here. Glad to see all the interest and so many successful builds of this speaker by others. Hope you are doing well.
I am really leaning towards speakers with passive crossovers. Have you made a passive XO design for the SynTripP yet?
Regards,
X
I haven't taken the time to do proper polar responses with a protractor to gauge the angles however I have been finding it much easier to dial in the EQ by taking measurements a bit off axis. Maybe 15 degrees off axis by my guess. Whenever I eq'd the speakers completely flat on axis i found them to sound a bit off when I set them both up to listen. Ive also found that they sound best having them both face straight forward or with very minimal toe-in especially with the secondary horns attached. I'm not sure if this is normal behavior for these speakers or just a result of how I built them or the drivers I used? At any rate I am extremely impressed with how they sound with very minimal EQ. It has definitely been a learning experience as this is the first time I have built/eq'd speakers. I often found the more i tried to eq the small dips and peaks in response the worse the final sound was.
As of now I've settled with +6db @ 130 hz, -7db @500hz for the mids. -2db @ 2.2khz and +5db High shelf @ 10khz on the Highs. Crossover 800hz 24/BW on the mids. 875hz 24/BW on the Highs. I tried the LR/24 at various crossover points for the highs but always ended up with a dip in the crossover region. Highs are delayed .52ms. Getting the delay right made a HUGE difference. I was originally using .4ms delay since that is what other people seemed to be using but the other day I played around with higher and lower delays and when I hit .52ms its like the speakers just snapped together. Female vocals were sounding a little bit hollow before the delay was dialed in but afterwards they sound absolutely fantastic. Here is the frequency response with the above EQ applied with secondary horn attached.
On another note I recently tested out the Hypex NC252 module on the compression drivers and am extremely impressed with the clarity, detail and low noise floor it provides. I also tested it on the mid drivers and it sounded fantastic on them as well so i was thinking of getting two more of the bigger NC502 modules to power the mid drivers. All three modules could then be installed into a single amp case to simplify my amp setup. According to their spec sheet the NC502 modules are rated for 350w x 2 into 8 ohms however they can also be bridged to provide 1200w x 1 into 8ohms in BTL. Could i then expect to get approx 800w into the mid drivers if i ran the mid drivers in series? I figure if the mid drivers average impedance is 6 ohms(3ohms in parallel) when run in the SyntripPs they would be about 12ohms in series? The Hypex modules probably wouldn't like being bridged into a 3ohm load as each side of the amp would only see 1.5ohms. The other option would be to run each mid driver separately however that would require me to get new speakon4 cables and connectors. Please let me know if my calculations are incorrect or if there is any other reason this shouldn't work. Cheers.
As of now I've settled with +6db @ 130 hz, -7db @500hz for the mids. -2db @ 2.2khz and +5db High shelf @ 10khz on the Highs. Crossover 800hz 24/BW on the mids. 875hz 24/BW on the Highs. I tried the LR/24 at various crossover points for the highs but always ended up with a dip in the crossover region. Highs are delayed .52ms. Getting the delay right made a HUGE difference. I was originally using .4ms delay since that is what other people seemed to be using but the other day I played around with higher and lower delays and when I hit .52ms its like the speakers just snapped together. Female vocals were sounding a little bit hollow before the delay was dialed in but afterwards they sound absolutely fantastic. Here is the frequency response with the above EQ applied with secondary horn attached.
On another note I recently tested out the Hypex NC252 module on the compression drivers and am extremely impressed with the clarity, detail and low noise floor it provides. I also tested it on the mid drivers and it sounded fantastic on them as well so i was thinking of getting two more of the bigger NC502 modules to power the mid drivers. All three modules could then be installed into a single amp case to simplify my amp setup. According to their spec sheet the NC502 modules are rated for 350w x 2 into 8 ohms however they can also be bridged to provide 1200w x 1 into 8ohms in BTL. Could i then expect to get approx 800w into the mid drivers if i ran the mid drivers in series? I figure if the mid drivers average impedance is 6 ohms(3ohms in parallel) when run in the SyntripPs they would be about 12ohms in series? The Hypex modules probably wouldn't like being bridged into a 3ohm load as each side of the amp would only see 1.5ohms. The other option would be to run each mid driver separately however that would require me to get new speakon4 cables and connectors. Please let me know if my calculations are incorrect or if there is any other reason this shouldn't work. Cheers.
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No, I abandoned that pursuit before selling the original SynTripP system over two years ago.