So I am a DJ and occasionally do live shows corporate work as well. Our typical event is 300 people or less, mostly indoors but occasionally outdoors. I am looking to really make my load in/out as simple and easy as possible. Dragging VRX subs and SRX tops in and out of venues by myself is doable but I am getting older now and it seems like it just gets a bit more painful every year.
I would like to go with a Passive rig that can be run by two QSC GXD8 amplifiers or something similar. Keep the processing in the amps and have a simple 5U case at 35lbs. For subs, I have built two of single 15 enclosures using Beyma 15LEX1600nd. The enclosures are complete minus the handles. Waiting for the drivers to come in so I can get the COG right. They should weigh in at right about 55-60 lbs and are very compact. Supposedly they get decently loud. I guess we'll see. If they perform well I intend to build two more for outdoor work.
I am struggling a bit with a design for a lightweight 2-way top. But ultimately I would like to us an RCF HF94 coupled with 2 B&C 8MBX51 mid/low drivers. I would like to hp them at 80 to 90 hz and crossover at 900 - 1000. I spent several days in winISD and the attached screenshots are what I came up with so far. In this design I have baffle between the low and high frequency section to keep my volume down. Ultimately, I would like to achieve a true 125db and be under 40lbs.
So besides and suggestions you might have, I have two questions:
1. Is there anything wrong with using a rear port on a PA speaker? I really struggled to find a balance in enclosure volume and port dimensions that were reasonable without exceeding cone excursion parameters. And I could save a few inches in height if I could move the port to the back.
2. Is there a particular compression driver you would recommend pairing with the HF94?
I would like to go with a Passive rig that can be run by two QSC GXD8 amplifiers or something similar. Keep the processing in the amps and have a simple 5U case at 35lbs. For subs, I have built two of single 15 enclosures using Beyma 15LEX1600nd. The enclosures are complete minus the handles. Waiting for the drivers to come in so I can get the COG right. They should weigh in at right about 55-60 lbs and are very compact. Supposedly they get decently loud. I guess we'll see. If they perform well I intend to build two more for outdoor work.
I am struggling a bit with a design for a lightweight 2-way top. But ultimately I would like to us an RCF HF94 coupled with 2 B&C 8MBX51 mid/low drivers. I would like to hp them at 80 to 90 hz and crossover at 900 - 1000. I spent several days in winISD and the attached screenshots are what I came up with so far. In this design I have baffle between the low and high frequency section to keep my volume down. Ultimately, I would like to achieve a true 125db and be under 40lbs.
So besides and suggestions you might have, I have two questions:
1. Is there anything wrong with using a rear port on a PA speaker? I really struggled to find a balance in enclosure volume and port dimensions that were reasonable without exceeding cone excursion parameters. And I could save a few inches in height if I could move the port to the back.
2. Is there a particular compression driver you would recommend pairing with the HF94?
Attachments
Yes, it greatly increases the amount of sound radiating from the back of the speakers which reduces GBF with open mics and increases fatigue for those standing behind the speakers. You might consider just making the cabs sealed
RCF nd850/950, 18sound nd1460
Thank you for that response! I’ll have to model this sealed. I thought that would seriously reduce the output.
In your opinion is there any glaring issues with the way I have it mocked up right now?
In your opinion is there any glaring issues with the way I have it mocked up right now?
A reflex enclosure only helps flatten response below 150-200hz, above that there would be no difference in output.
No looks good. What thickness cabinet material are you considering and is the box rectangular or trapazoid? I built some 12" 2-way trapazoid cabs with 1/2" material that are quite rigid, that shape helps with that but it does add some build complexity.
If you use two similar woofer and a horn put the horn in the middle. Sound will be audible better, flatter and even a bit louder. Vented makes no sense if you divide from 80-150 Hz. The louder you need the speaker, the higher you can cut them of. This gives you some flexability, if the compression driver is beefy enough I must add.
The wedge style is questionable for DIYS. It makes building a lot more complicated without any measurable advantage. If you need a stage monitor, that's something different, because you want them flat and pointing up.
The wedge style is questionable for DIYS. It makes building a lot more complicated without any measurable advantage. If you need a stage monitor, that's something different, because you want them flat and pointing up.
why not use 2x 10" woofers? horn is about 10" wide and I would guess that 125db @ 80hz is a stretch for 8" woofers.
Yea I should have clarified. The dimensions shown are internal dimensions. 10”w 9.25d and 29” tall. But the woofer portion will only be 19” tall. Port is currently 2x10 and 6” deep. Square rather than trap. I plan to use 15mm Baltic birch.
Also, I do have a decent amount of experience woodworking and and have the appropriate tools to build a trap cabinet but I tend to like to keep it as simple as possible.
In such a build you can combine hardly any PA chassis you like and that fits the bill.
The cabinet is quite simple, you only need a reasonable volume.
All the art comes from the crossover matching horn and woofer. That is where you miss or hit.
The cabinet is quite simple, you only need a reasonable volume.
All the art comes from the crossover matching horn and woofer. That is where you miss or hit.
Thanks for these responses! This evening I tried modeling various sealed options both 8" and 10". So far what I am seeing is a significant drop off from 150hz to 80hz. I am inclined to at least try this design and see how it sounds. I guess it could be a waste of money but we'll see. Also looking at commercial options that might work. The Nexo P15 is pretty close though very expensive. If you have other suggestions I should look at let me know. I am certainly not stuck on reinventing the wheel if there is a good option out there already, though I do enjoy building. At the end of the day, its a business right.
Regarding the crossover: I well that a whole other chapter. I guess I could biamp them for now and use dsp for sorting things out? I don't know how easy those results would be to replicate in an actual crossover though.
Regarding MTM vs MMT: I don't know that I have a strong opinion on this. I have heard both sound really good. I've always enjoyed the sound of the Yorkville U215 as well as the QRx 212. I'll have to think about that some more.
Regarding the crossover: I well that a whole other chapter. I guess I could biamp them for now and use dsp for sorting things out? I don't know how easy those results would be to replicate in an actual crossover though.
Regarding MTM vs MMT: I don't know that I have a strong opinion on this. I have heard both sound really good. I've always enjoyed the sound of the Yorkville U215 as well as the QRx 212. I'll have to think about that some more.
I would advise against sealed cabinets for PA, especially for dance music where the bass is hyped. You might want +10db at 80hz compared to 1600hz, that leaves you with a max SPL of only 115db for your horn. Even low signals at the tail of the woofers' high-pass filter will cause large excursions. With peak SPL of 125db and a 4th order XO at 80Hz, the signal at 40Hz is only -24db down or 101db. Typically for an 80hz crossover you would have a vented tuning at like 60Hz, or perhaps 70Hz max. And IMO you should be using 4th order XO everywhere, both for excursion control and minimized lobing. Don't forget your woofer has to play up to (and beyond) the horn XO while it's hitting Xmax to produce the low end, creating midrange distortion. Also air circulating in the cabinets is a good thing, even if your two 8" drivers are rated for 800W peak each you are gonna get thermal compression long before that. Big picture: get your SPL from surface area, support it with reflex tuning, and keep excursion to a minimum.
Yea I meant: I’m inclined to stick with my initial vented design. Thank you for that feedback. I may need to reevaluate my design cause I currently have it tuned at 80hz due to excursion problems.
About 5% of speed of sound.
A horn on top and two identical woofer under it will give a comb filtering problem, which any serious designer who learned his math will try to prevent.
The 80 Hz filtering of tops is burned into peoples mind, because it is the THX home cinema cut of. With a PA there is no advantage to go that deep with the tops. Any bass you put into the mid driver makes it sound more stressed. Just try it out when you set up such a system the next time. A higher cut will sound better. 120 Hz is often best for sound and spl.
With todays chassis there is no advantage from running tops vented. Vented makes sense where high cone excursion takes place. It only adds volume and group delay to the tops you don't like there. If you want to run them without a sub, that is something else, but not anyone likes a fridge sized speaker on a stick...
Anyway, speaker building is a free discipline, you can build what you want and will get what physic dictates.
A horn on top and two identical woofer under it will give a comb filtering problem, which any serious designer who learned his math will try to prevent.
The 80 Hz filtering of tops is burned into peoples mind, because it is the THX home cinema cut of. With a PA there is no advantage to go that deep with the tops. Any bass you put into the mid driver makes it sound more stressed. Just try it out when you set up such a system the next time. A higher cut will sound better. 120 Hz is often best for sound and spl.
With todays chassis there is no advantage from running tops vented. Vented makes sense where high cone excursion takes place. It only adds volume and group delay to the tops you don't like there. If you want to run them without a sub, that is something else, but not anyone likes a fridge sized speaker on a stick...
Anyway, speaker building is a free discipline, you can build what you want and will get what physic dictates.
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@kweaver
Ever considered a good fullrange driver like Fane SOVEREIGN 12-250TC?
You omit all problems with crossovers and a simple EQ can adjust the sound.
Its always then a phase linear system, too, bringing better impulse response then multi ways usually do.
There is a complete thread on it
https://www.diyaudio.com/community/threads/new-12-full-range-fane-12-250tc.246746/page-34
Ever considered a good fullrange driver like Fane SOVEREIGN 12-250TC?
You omit all problems with crossovers and a simple EQ can adjust the sound.
Its always then a phase linear system, too, bringing better impulse response then multi ways usually do.
There is a complete thread on it
https://www.diyaudio.com/community/threads/new-12-full-range-fane-12-250tc.246746/page-34
One pair of tops doesn’t necessarily do everything well. If you are serious about doing DJ, PA, rental or otherwise, there won’t be just one pair in your arsenal. You bring what’s needed and if the gig needs a heavier cabinet then so be it. You can get some damn fine neo 12’s that will put out the 80 Hz when needed if you are willing to drop $400 a pop - hell the 1.4” CD that will keep up will cost that much - (getting the same in a powered cab will be in the $2000 range). Trying to do the same with 8’s is a fools errand. When the 8’s are enough which may be most of the time you can save your back and pack space. And you only need one sub out of the 4 or 8 on hand.
If you just don’t have everything you need to do the bigger gigs when you first start out that’s ok. None of us did, except the ones who took out a second mortgage specifically to “go into business”, and then the primary goal is profit not SQ. Needing new gear gives you the excuse you need to build more speakers. After 20+ years, you may end up with a warehouse full of the stuff.
If you just don’t have everything you need to do the bigger gigs when you first start out that’s ok. None of us did, except the ones who took out a second mortgage specifically to “go into business”, and then the primary goal is profit not SQ. Needing new gear gives you the excuse you need to build more speakers. After 20+ years, you may end up with a warehouse full of the stuff.
Well the truth is 98% of the work I do is 300 people or less. Weddings, Corporate and smaller bars. Most are more like 200 or less and indoors. I don’t really have any desire to do big shows and honestly there is almost no demand for that around here. I do have a pair of Renkus Heinz CT5’s and some dual 18’s that I use maybe twice per year for more demanding outdoor work.
I’m not really looking for a one size fit all solution. I am trying to put together a very compact, lightweight system that will do 200 to 300 people indoors and sound very good. I just haven’t found a production top or sub that really falls into that category for less than $4k a piece. I have a budget of $2k or less per unit if I can’t do for less that $2k per, I’ll just bite the bullet and go with something like the Nexo P12 but that will cost significantly more than $2k
Currently running SRX 815p’s and VRX918sp subs. The systems sounds okay and gets reasonably loud. It’s just too heavy and bulky for a 1 man show.
I’m not really looking for a one size fit all solution. I am trying to put together a very compact, lightweight system that will do 200 to 300 people indoors and sound very good. I just haven’t found a production top or sub that really falls into that category for less than $4k a piece. I have a budget of $2k or less per unit if I can’t do for less that $2k per, I’ll just bite the bullet and go with something like the Nexo P12 but that will cost significantly more than $2k
Currently running SRX 815p’s and VRX918sp subs. The systems sounds okay and gets reasonably loud. It’s just too heavy and bulky for a 1 man show.
Well the proposed 2x8 will likely blow away anybody else’s rig if they are using the typical $699 powered cabinets (Which also include retail markup and an amplifier in the price - think about that). They will just run out if steam eventually. 300-person events can vary drastically in the expectations of how loud/powerful the sound needs to be. You may have SPL limits imposed or it could be that too much is not enough.
If you need louder tops and redundant built for security you can make a two or more driver array with the
Fane 12-250tc.
For this you build several closed boxes with them and you can also turn one box slightly so you get a better coverage of the high frequencies if needed.
Found measurements of it on Audiosciencreview
Fullrange means perfect time response naturally after being EQed - but many tell this driver works seriously good right out of the box.
https://www.audiosciencereview.com/...overeign-12-250tc-project-measurements.35301/
Fane 12-250tc.
For this you build several closed boxes with them and you can also turn one box slightly so you get a better coverage of the high frequencies if needed.
Found measurements of it on Audiosciencreview
Fullrange means perfect time response naturally after being EQed - but many tell this driver works seriously good right out of the box.
https://www.audiosciencereview.com/...overeign-12-250tc-project-measurements.35301/