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Old School Audiophile has a few DR questions????

kpippenkpippen Posts: 551
edited April 2010 in 200 Series Connectivity
Hello,

I was a 1970's Audiophile and I have not been around audio very much since the mid 1980's... I am fifty years old and I'm attempting to install a decent sound system in our church's new youth sanctuary... I have been spending a lot of time on the ProSoundWeb.com forum lately, trying to brush-up on the current technology and the even more difficult \"terminology\"...

Holly crap,...active crossovers were somewhat experimental in my days...

Last night I was looking at the DBX 231 GEQ and 223XL Crossover and I stumbled upon the DriveRack PA... And since then I have also looked at the DR260...

Before I ask a few questions here is what I'm dealing with due to budget:

Room size - 72FT Wide X 46FT Deep with sound stage centered on the 72FT width
Mixer - One Hand-me-down Yamaha MX200-24 (No complaints here)
Amps - Four brand new Behringer EP2500 (QSC RMX-2450 Clones)
Floor Mains - Two brand new JBL JRX125 (One on each side of stage)
Flying Mains - Four brand new JBL JRX115i (Two hanging down 30deg and facing-in 15deg on each side of stage)
Sub - One or maybe two brand new JBL JRX118S
Wedges - Six brand new BBL JRX112M

1) After reading through a lot of the DriveRack Archives I have not seen any mention of wedges or monitors?... I am curious in how most of you are applying them? I could really use some help here!...

2) Also, could I use the DriveRack crossover successfully in the following way without modifications to the speakers or bypassing their passive crossovers:

High = flying JRX115i
Mid = JRX125
Low = JRX118S

Thank you so much for any advise!...
«13456711

Comments

  • wolfgongwolfgong Posts: 74
    I'll just comment on what I know here.

    A couple of questions up front need to be answered:
    A Are you planning to run the system in stereo? This will effect what channels are available to use going forward.

    B In your installation are the speaker cabinets all aligned in time or will the 115's require a time adjustment relative to the 125's?

    C I'm assuming the sub will need some time alignment.

    These configuration design considerations will effect how you could leverage a driverack for this installation.

    Now for your questions.
    A Monitors/wedges usually receive a completely different mix than the house speakers and generally the driverack 260 is used on the main house system. I think that is the most likely application of a driverack for your application.

    B The suggested crossover settings you have are not completely appropriate for the speakers you have listed. The 125 and the 115 speakers are both 'tops' designed to respond in the high frequency range down to the mid to low range. By reading the doc on the JBL sight I gather they have their own crossovers buit in at 2000Hz. You could use the drive rack to set the crossover point between these speakers and the sub(s). In other words you got the low part right in your proposed crossover choices.

    Let me know if you're going stereo and we can start working from there.

    In planning an installation it really helps to make a diagram, so if you could post something simple, even like a powerpoint with some crude demensions on it, that would save us considerable confusion in our future discussions.

    Thanks.
  • GadgetGadget Posts: 4,915
    Yo wolf,
    I think what he means is can the mids serve as a separate output and the answer is yes. It would be a 2X6 even if you run mono just use one side of the unit. then (with the 260) you could have one monitor mix you could do. I suspect and HPF of 45 hz @BW18 and a 100hz LR24 HPF cross should do the trick to start. Yes I use a driverack on the monitors and it works great.

    you can set the 125's on the mid outs I would suggest 120 hz for those and the 115's on the hi outs @ 100 hz as long as they aren't covering the same area. any other questions.. BTW the 260 is the bomb!
    Gadget
  • wolfgongwolfgong Posts: 74
    Gadget -

    What are you doing up at 7:38AM?!?!

    We'll see what kpippen meant by hi, mid, low.

    I think you should be getting some form of remuneration from DBX for all your info about driveracks.

    I also think that if the general public understood what a driverack is and what it can do, (auto EQ for example), DBX could sell thousands of them.

    See ya!
  • kpippenkpippen Posts: 551
    Hello Wolfgang and Gadget,

    Last week I bought a DR260!... I have to be out of town for the next two days and as soon as I return I will post some more information (.pdf layout drawing)... I downloaded the software and have been getting myself famialure with it... I should recieve my 260 sometime next week... I thank both of you so very much for replying to my post and I can really use your advise... I guess I will have to do a \"custom\" 2X6 configuration because of my speakers and amps...

    Thanks!

    Kevin
  • kpippenkpippen Posts: 551
    wolfgong wrote:
    We'll see what kpippen meant by hi, mid, low.

    Hi Wolfgang,

    Sorry, I meant HI range Freq, MID range Freq, and LOW (sub) range Freq. I will post a drawing .pdf layout drawing soon...

    Kevin
  • wolfgongwolfgong Posts: 74
    No worries.

    A PDF would be awesome. I think you may start a trend in communication here on the DBX forum.

    See ya soon.
  • kpippenkpippen Posts: 551
    edited April 2007
    Hello Wolfgang and Gadget,

    I appologize for taking so long to post this information. I should receive my driverack 260 this Monday (I hope). I have played with the software a little bit in regards to a stereo 2X6 crossover. Since my speakers and amp aren't listed in the software I guess I have to do a custom setup?

    I now have a .pdf drawing of the room and speaker layout but I don't see how to attach it? I would also like to attach the driverack config I did as well...to ask if I am even close to a starting point with this system. In the mean time...until I figure out how to attach these files I thought I would go ahead and post the final configuration (with specs) update:


    ROOM SIZE - 72FT Wide X 46FT Deep with sound stage centered on the 72FT width


    MIXER - One hand-me-down Yamaha MX200-24 (No complaints here)


    AMPLIFIERS - Three brand new Behringer EP2500 (QSC RMX-2450 Clones) for high-mid, mid-low, and low frequency ranges.

    SPECIFICATIONS:
    Output Power:
    20 Hz – 20 kHz @ 0.1% THD, both channels driven: 450 watts @ 8 ohms / 650 watts @ 4 ohms.

    1 kHz @ 0.1% THD, both channels driven: 500 watts @ 8 ohms / 750 watts @ 4 ohms / 1200 watts @ 2 ohms

    Bridged Mono:
    20 Hz – 20 kHz @ 0.1% THD: 13000 watts @ 8 ohms
    1 kHz @ 0.1% THD: 1500 watts @ 8 ohms
    1 kHz @ 1.0% THD: 2400 watts @ 4 ohms

    Distortion: <0.02%
    Frequency Response: 20 Hz – 20 kHz, +0/-1dB
    Frequency Response: (at 10 dB below rated power) 5 Hz – 50 kHz @ -3 dB points
    Damping Factor: >300 @ 8 ohms
    Noise: (unweighted, 20 Hz – 20 kHz) -100 dB
    Voltage Gain: 50 X (34 dB)
    Input Sensitivity, V RMS (@ 8 ohms): 1.23V (+4.0 dBu)
    Input Impedance: 10k ohms unbalanced, 20k ohms balanced
    User Manual: http://www.behringerdownload.de/EP1500_ ... _Rev_D.pdf


    FLYING MAINS - Four brand new JBL JRX115i (Two hanging down 30deg and facing-in 15deg on each side of stage). Two pairs wired in parallel @ 4 ohms per pair for high to mid Frequency range.

    SPECIFICATIONS:
    Speaker Type: 15� 2-way, sound reinforcement speaker
    Frequency Range (-10 dB): 38 Hz – 16 kHz
    Frequency Response (+/-3 dB): 50 Hz – 12.5 Hz
    Sensitivity (1w/1m): 98 dB SPL
    Nominal Impedance: 8 ohms
    Power Capacity: 250 watts
    Peak Power Capacity: 1000 watts
    Recommended Amp: 250-500 watts @ 8 ohms
    Maximum SPL: 128 dB
    Nominal Dispersion: 90deg X 50deg
    Cross Over Frequency: 1.6 kHz
    Spec Sheet: http://www.jblpro.com/JRX/pdf/JBL_JRX115i%20final.pdf


    FLOOR MAINS - Two brand new JBL JRX125 One on each side of stage for mid to low frequency range.

    SPECIFICATIONS:
    Speaker Type: Dual 15� 2-way, sound reinforcement speaker
    Frequency Range (-10 dB): 35 Hz – 16 kHz
    Frequency Response (+/-3 dB): 45 Hz – 12 Hz
    Sensitivity (1w/1m): 100 dB SPL
    Nominal Impedance: 4 ohms
    Power Capacity: 500 watts
    Peak Power Capacity: 2000 watts
    Recommended Amp: 500-1000 watts @ 4 ohms
    Maximum SPL: 133 dB
    Nominal Dispersion: 90deg X 50deg
    Cross Over Frequency: 2 kHz
    Spec Sheet: http://www.jblpro.com/JRX/pdf/JBL_JRX125%20final.pdf


    SUBWOOFERS - Two hand-me-down EAW VRS18 Floor subwoofer speakers for low frequency range.

    SPECIFICATIONS:
    Speaker Type: 18� bass reflex subwoofer
    Frequency Range (-10 db): 31 Hz – 145 Hz
    Axial Sensitivity (whole space SPL): 93 dB, 31 Hz – 145 Hz
    Peak Sensitivity (whole space SPL): 98 dB, 20 Hz – 20 kHz
    Nominal Impedance: 8 ohms
    Power Capacity: 500 watts, 64 volts @ 8 ohms
    Maximum SPL (average) 120 dB
    Maximum SPL (peak) 126 dB
    Recommended High-Pass: > or = to 25 Hz, @ 24 dB/octave (butterworth)
    Recommended Low-Pass: 100 Hz, @ 24 dB/octave (butterworth)
    Recommended EQ: 50 Hz, +3 dB, Q=2
    User Manual: http://www.eawcommercial.com/en/product ... S18_IM.pdf

    I will post the .pdf drawing attachment and driverack config file as soon as I figure out how to do it....

    Thanks!

    Kevin
  • kpippenkpippen Posts: 551
    Hello Wolfgang and Gadget,

    Please see the following links for the .pdf youth room, speaker and sound stage layouts... The purple and blue boxes represent the JBL JRX115i flying speakers (high-mid range), and the red box represents the JBL JRX125 floor main speakers (mid-low range)... We ended-up hanging the JRX115i's about 16\" higher than the drawing shows... All of the other deminsions and angles are correct... The subwoofers will be on the floor next to the JRX125s.

    http://www.teamaai.net/kevin/Youth/Yout ... Layout.pdf

    http://www.teamaai.net/kevin/Youth/Yout ... Layout.pdf
  • wolfgongwolfgong Posts: 74
    Wow. This is great. Nice to have the pictures.

    First some good news. I think if you download the new firmware (1.5) the JRX speakers will be in the list. See this posting url for more info on 1.5 firmware content. http://www.dbxpro.com/forum/viewtopic.php?t=622

    I'll print out these diagrams and start looking at them. I'm sure Gadget will have some good info on 260 config.

    It looks like we will need some time alignment settings.
  • kpippenkpippen Posts: 551
    Hello Wolfgong and Gadget,

    WOW...I lucked out with the new firmware and software update! Not only does it have the JRX speakers but also has the QSC RMX2450... I downloaded both of the updates and was able to get some initial settings with the software.

    Our two youth praise teams like to play loud and hard, and ofcourse...they like a lot of bass!.. We are planning to DI all of the instruments through the PA. They mainly use vocals, acoustic electric and electric guitars, acoustic electric and electric bass, and drums... I purchased some Shure SM58s (vocals), SM57s (for amp miking if needed), Countryman type 85, LR Baggs Para Acoustic, Radial J48, and Tech 21 SansAmp Bass Driver DI boxes. The reason I purchased so many speakers is becuase I wanted to fill the room with sound, and to allow these kids to blow-out their ear drums before the speakers...

    I was hoping to take full advantage of the speakers I bought by overlapping the 2X6 crossovers... If you don't mind emailing me I would like to reply by sending you the DR260 config file I did...to see what you think... I would like to take advantage of the feedback suppression and sub-harmonic synthesis but I not exactly sure where they are located in the software?... I enabled the email feature for my user name...

    Thanks!

    Kevin
  • wolfgongwolfgong Posts: 74
    Kevin -

    Can you post the file on the same server as the pdf files? Then we can look at it.

    Where abouts approximately are you located?
  • kpippenkpippen Posts: 551
    Hi Wolfgong,

    I am located in Georgetown, KY which is just North of Lexington. I have uploaded the DR260 device Harmony_Youth.dwd file to the server.

    http://www.teamaai.net/kevin/Youth/Harmony_Youth.dwd

    Please take a look and tell me what you think...

    Kevin
  • wolfgongwolfgong Posts: 74
    Kevin -

    It looks to me like you understand this driverack pretty well.

    The routing looks good and I see you have crossovers set.

    How soon before you can install this unit? I'd like to see what the EQ looks like after you auto EQ it.

    I did an auto EQ here in a school gym and it was nothing short of incredible the difference in clarity and image the auto EQ provided. Not like doing the 31 band EQ by ear. : )

    When I did the auto EQ, I made sure I had about 85 spl, according to an inexpensive Radio Shack SPL meter so that the analyzer mic can 'hear' everything well enough to make it process work.

    I'll take another look at your diagram, the crossover points and the specs for your cabs and see what I think.

    I'm curious as to how you arrived at your 125L HPF frequency.

    Nice work, keep in touch!
  • GadgetGadget Posts: 4,915
    Kippen ... did you get my PM?
    Gadget
  • wolfgongwolfgong Posts: 74
    Kevin -

    After looking at your crossover settings, I believe you are going to want to set your mains (115 & 125)s with the same low frequency rolloff frequency, (HPF) say around 100Hz. Then you will also set your subs High frequency rolloff point to the same frequency(LPF).

    Next I would take a listen with a favorite music CD. See what you think about the sound near the crossover point. Are bass lines sounding right, etc.

    Then I would put up some pink noise and see if there is a hump or dip at the crossover point. If there is no big variation at the crossover point, then I would go to the auto EQ and run that process.

    At some point you will need to time align your cabinets, too. That can be done by taking a measurement of the offset between cabnets and using that in the delay setting for that output.

    This is a lot to try to communicate in text I think I will see if I can get you my phone number.
  • kpippenkpippen Posts: 551
    Hi Gadget,

    No...I did not... Please shoot me an email...

    Thanks!

    Kevin
  • kpippenkpippen Posts: 551
    Hi Wolfgong,

    Keeping the JRX115s and JRX125s the same was also suggested by Mike with DBX in an email yesterday... I posted my original updated configuration idea on the server to get more advice and another opinion...

    What Mike and you suggested is what I will be starting out with... You guys have been a real blessing in helping to me to get good starting point... This evening I will make the adjustments and upload the new configuration for your review...

    I would also like to get Gadgets opinion as well... I have read a lot of his post and it's obvious to me that he...like yourself has had a lot of experience with the DriveRack 260...

    I'm glad you mentioned setting the system for 85 dB when running the auto EQ... There is so much to consider I completely forgot about that... I will also have to get a dB meter at Radio Shack...

    Yes...please shoot me an email with your phone number I would really appreciate speaking with you...

    Thanks!

    Kevin
  • GadgetGadget Posts: 4,915
    Have you checked your person mail?
    G
  • kpippenkpippen Posts: 551
    Hi Gadget,

    I have checked my PM twice today and I have nothing in my INBOX... Must be a DBX Forum problem?... Please email me using the email button on the bottom of this post...

    Thanks!

    Kevin
  • kpippenkpippen Posts: 551
    Hello Wolfgong,

    I changed the crossover as you suggested... The EAW manual for the VRS18s (sub-woofer) recommends the following:

    Recommended High-Pass: > or = to 25 Hz, @ 24 dB/octave (butterworth)
    Recommended Low-Pass: 100 Hz, @ 24 dB/octave (butterworth)
    Recommended EQ: 50 Hz, +3 dB, Q=2

    I would like to set the high pass at exactly 25 Hz and the low pass at exactly 100 Hz... For some reason I when I move my mouse the numbers jump all over the place?... Tell me if the following revised is what you suggested:

    http://www.teamaai.net/kevin/Youth/HarmonyYouth.dwd

    Kevin
  • GadgetGadget Posts: 4,915
    Well... What I wrote was... that you wouldn't like much my response to your setup...I didn't send it direct to you in email form because there are always a lot of lurkers here that might benefit from the information.

    Its important to note here that each speaker has a coverage pattern that is very much specified for a reason. Your coverage plot shows a lot of overlapping coverages and I know you stated that you wanted to blow \"ears and not speakers\" some would crucify you for that remark.. not me.. I have brutalized my ears in numerous forms for what seems like a thousand years.. I am \"older than dirt\" after all... I am \"the old sound man\"... and I have better than average 30 something hearing... BUT it should however be pointed out that you should be warned that you leave yourself open to a thousand problems by allowing the \"youth\" to subject themselves to what \"OSHA\" says are dangerous sound pressure levels... that said.. and thats the last you'll hear of it from me...we will now move on to coverage patterns and the pitfalls of overlapping coverages...

    As laid out wherever you have overlapping coverage you will have lobing and modes, and nulls and all manner of sound wrecking havoc. Most of the modes, finger like areas where you will hear sound just fine and move a few inches and there will be nothing or very little sound and so on across the room... Or it will be a null where there is a total lack of a certain frequency area that moves throughout the room... this could crush a voice... eliminate a guitar remove a complete bass note...or in the case of low frequencies check out \"boundary cancellations\" and all of these problems have been dealt with ad-infinitum in the\"former forum\" listed in a link above under \"tutorials\". The first problem is dissimilar speaker in the same coverage area... the second is multiple planes of coverage and the third is overlapping coverage on the hung speakers....those hung speakers should be right together...side by side with the sides together so that two speakers placed side by side will (without ANY overlapping of coverage in the horn pattern area) provide 180 degrees of coverage. thats two 90 X 50 horns... now when you have the left and right 180 degree patterns set up they interact too... but not like when they are right on top of each other like yours...The speakers on stage would be better utilized in a stage wash where they cover the stage and front row but not too far back where they interact with the flying mains...That means that they should be on stage left and stage right. Another problem is reflective surfaces... keep the sound off the walls, ceilings, and on the people.

    More bad news... Sorry the mixer you have... even though it was donated is ... well can I just say that I cannot believe yamaha could (given their vaunted status as tour grade equipment) produce a mixer with so little headroom on the pre's and such a horseshit EQ section... again sorry...
    ALSO this proclivity to want presets for amps and speakers... especially those with no need for crossovers.. like the JRX series by JBL...( you will only find speakers that are Bi ampeable or tei ampable and so on in the presets menus because fullrange speakers DON\"T NEED CROSSOVERS... and if they have listed crossovers they will have a SPECIFIC sub listed .. and if that sub is not used the info is suspect with any other sub...

    ALSO... amp sensitivity where optimized systems, both speakers and amps , are not being utilized. Its a panacea, and has no business being postulated where all the facts aren't known and where gain structure should be used to determine amp settings.

    I'm not trying to be a curmudgeon here, but there is so much more to this than you guys realize and its been dealt with so much over the years... and it is complicated...and it requires a huge amount of knowledge.. and explaining it in less technical terms is difficult and time consuming. This driverack system requires a lot of knowledge.. knowledge I had to learn on my own, there was no Gadget or Mikey when I got my unit...But thank GOD for the internet... I was able to employ my years of sound production with the info available on the net and figure out what these systems can do and its intimidating at first, but you need to get the basics, then start delving into sound propagation and sound reinforcement techniques and know what each module does and why...only then can you justify the technology, and maximize its potential. I have provided the links I used, the important factors I found and the shortcuts I have implemented.

    Ok... I'm going to let you digest that then when your done being shell shocked I'll let you ask questions then I'll give you my starting points and some tuning techniques...

    I will say this... don't even THINK of setting the subs up like you specified in your last post... you have no where NEAR the power...or the expertise to keep from blowing up the amps AND the speakers...using those amps, you better set an HPF of 40-45 hz minimum. I suggest BW 18 slope, and with the 12's, 100 hz is too low...Again I'm NOT a fan of JBL... PERIOD.. ESPECIALLY the low line speakers... you can get so much more... and for so much less you can can get BETTER performance and a whole lot less grief if you have problems...

    Ok rant off.. and as I said I'm sorry but I have been quiet on this thread for too long ... and I DID write all this a while ago...BUT somehow I never got it posted.. So I'm outa here..

    Gadget
  • kpippenkpippen Posts: 551
    Hello Gadget,
    kpippen wrote:
    The reason I purchased so many speakers is because I wanted to fill the room with sound, and to allow these kids to blow-out their ear drums before the speakers...

    I guess I should have put a HA-HA or a HEE-HEE at the end of that sentence… That remark was tongue-in-cheek… I guess this only proves that a lot is missed in the communication of writing… You can’t see a person’s eyes, facial expression, etc., etc…

    A little history here… My church recently purchased and converted an old Wal-Mart to our new church home.

    http://www.youtube.com/watch?v=eYjLtRGnN1w

    http://www.kentuckyconnect.com/167/story/37706.html

    By the time we got to the youth sanctuary we were way over budget and out of money… Several of our youth's parent’s stepped-up-to-the-plate and donated their time and effort in various areas... Unfortunately, I guess…I decided to provide our youth with a new stage and sound system… I’m a very blessed man…a father of three kids (a daughter, and two sons..a guitarist, and a drummer) that wants to give a little something back to the Lord… Truth be known…I had already purchased over $$,$$$.$$ in materials and equipment before I was informed that limited financial aid would be available to me… You may find this hard to believe; but even with the “low end� equipment I purchased…the youth will be getting a far better system then what they had before…

    Because I’m not an “old sound guy� or “knuckle buster� I read a lot of post on this forum and prosoundweb before I decided to ask for help…and taking the risk of getting blasted… Somewhere on this forum I read the following which made me feel a little more comfortable in posting here…

    “You might take your question to the PSW (prosoundweb.com). Go to the LAB (live audio board) and post your question there. The folks that hang out there are the heavey hitters that use that type of system. You are far more likley to get a response there... just be carefull what you say, they can be kind of a heartless bunch if you come across the wrong way.�

    I just want you to know…and I say this in all sincerity: this forum is very blessed to have people like yourself, mikey, and wolfgong...that are dedicating their time, and sharing their valuable experience and knowledge… I still have not received my DriveRack 260 yet…but because of this forum I already feel a lot more comfortable with it… I will try my best to apply your advice to this project!... I’ll have you know this...I’m already dreading the re-hanging of those speakers… Do you think I should give them a try as they are now...before moving them?...

    I thank you so very much for your comments!

    Kevin
  • GadgetGadget Posts: 4,915
    Certainly... As you said this is for the kids and they will probably LOVE it and never know of the problems I described...no need to do anything if you don't want to I'm just trying to disseminate the correct info and make sure that those that read the threads get the correct info and not something that is going to cause them problems out in the pro world. I was the one suggesting the Pro forum and I am a member as well but you better wear flame proof underwear if you try and post there without knowing what your doing. Most \"newbies\" find themselves in the basement.. moved there by the moderator. Determining the delay is going to be the problem. With the 12's flying I would go 120 hz crossover LR24. I'd also HPF the subs @ 45 hz BW 18 since you have limited power. If you have an audio sweep generator I can tell you how to determine crossover delay more accurately than simply sweeping and listening for a change.

    You could run the 115's at 100 hz.. maybe if you look at the plot you could go lower but you'd need to add some LF equalization to get flat response but its possible.

    Anything else?
    gadget
  • kpippenkpippen Posts: 551
    Hello Gadget,
    Gadget wrote:
    Determining the delay is going to be the problem. With the 12's flying I would go 120 hz crossover LR24. I'd also HPF the subs @ 45 hz BW 18 since you have limited power. If you have an audio sweep generator I can tell you how to determine crossover delay more accurately than simply sweeping and listening for a change.

    You could run the 115's at 100 hz.. maybe if you look at the plot you could go lower but you'd need to add some LF equalization to get flat response but its possible.

    What do you mean by 12's flying?... The 115s have 15" speakers... Also, I didn't mention that I purchased one spare EP2500... Do you think it would be good to bridge mono two of the amps (one on each channel) for driving the subs?... Also, I'm assuming the following for a starting point...for example: I can measure the distance from the 115s to a given listening point, and then from the 125s to that same point and set the delay accordingly?... I'm assuming the closer of the two will require delay?...

    I'm very sorry for all of the questions!...

    Just so you know I do understand most of the lingo...I'm just not comfortable enough to use it myself...

    Kevin
  • kpippenkpippen Posts: 551
    Hi Gadget,

    Please take a look at the following revised file... I changed the HPF and crossovers taking what you suggested... I set the JRX125s at 100 Hz because they have dual 15\" speakers and are capable of more low-end than the 115s... I'm thinking that I should also use two bridged amps to drive the subs and to handle that low-end power?... I plan on putting the 115s right next to each other toe-in 15deg with the sides almost touching each other for 180deg coverage as you suggested... I will bring the 125s closer to the stage...and maybe toe-in about 15deg?.. What are your thoughts about putting the 125s right on top of the subs?...

    Here is the revised file:

    http://www.teamaai.net/kevin/Youth/HarmonyYouth.dwd

    Let me know if I'm on target....

    Thanks!

    Kevin
  • kpippenkpippen Posts: 551
    edited April 2007
    Hello Gadget,

    I stopped by the church this morning to take another look at how I hung the flying JRX115s... After a little more reading I think what your telling me is that the closer I can get them together the less comb-filtering effect I will have...or notice?... Also, I should have unequal distances to the speakers cab from the side and back walls?... Since the speakers are slightly wedge shape I'm thinking that it is best to mechanically tie them together on the back side of the cabinets to closer achieve the 180deg dispersion you mentioned... I need to re-hang these pretty quickly because the building is very close to being finished and man lifts are getting harder to find...

    Due to structural interferences here are my options: I can move one of the 115s on each side and hang them together at either the close to the stage area position or close to the side wall area position... Unfortunately there is duct work interference between the two original locations... If I hang them together at the close to the stage area they will also be much closer to the JRX125s and subs below... Would this increase yet another comb-filtering effect?... If I hang them close to the side wall area should I toe them in a little more?... I'm assuming that all speakers should be kept in-phase?... The current flying 115 locations are indicated by the blue and purple boxes on the original .pdf drawing I posted for reference:

    http://www.teamaai.net/kevin/Youth/Yout ... Layout.pdf

    As you suggested I will place the 125s closer to the stage...but what do you think about putting the 125s right on top of the subs? If I put the subs on platforms about 10-12\" off the floor the 125s would be very close to the ear level listening levels... Originally I was going to put the 125s on 24-26\" platforms...

    I know this is crazy and defeats common practice (like everything else I've done thus far) but,...I ran two 10AWG oxygen free speaker cables about 80ft in parallel to every speaker location... Unfortunately due to other issues I can't place my amps any closer to the loads... My insertion loss to each location is less than .2 ohms... My fluke meter indicates it to be closer to .1 ohms... I terminated the 10AWG on terminal boards at each end... I have about 10ft of 13AWG between the amps and a terminal box on one end, and about the same distance between the speakers and a terminal box on the other end... My old audiophile memory (or what's left of it...due to \"over exposure\" in the seventies) told me to keep my right and left channel cables at equal lengths... I know this is all over-kills (I think) but any correction in this area later down the road would be very difficult to do...

    I know that the kids will be absolutely delighted with anything I install,...and I'm very sorry for picking your brain so much... I've always had this major character flaw: perfection... It will bug me to-no-end if I can't convince myself that I installed the best system possible for the budget...

    OK now...with that being said...fire at will, and let me have it!...

    Once again,.. I thank you for all of your advice and help!!!

    Kevin
  • GadgetGadget Posts: 4,915
    OK.. NOW WERE TALKING!
    You learn quick.. in closer to the stage unless you can't get the sound off the walls in that position...try and keep the sound off the reflective surfaces...unequal dimensions are better...57 \" 33\"..etc versus (as most structural engineers would do) 50\" 48\" etc. Also, Go here:
    http://www.mcsquared.com/metricmodes.htm
    and put into the room mode calculator the rooms dimensions and get a handle on the room modes..It will help you determine how to best address them.

    Yes it would work to place the 125's on the subs, but at the back of the stage aimed strait forward you'll have problems with feedback. Consider moving the subs forward to the sides, and washing the stage and front rows with the 125's make sure the subs are more than, or less than 3 and 1/2 feet from and boundary to avoid boundary cancellation...

    Nothing wrong with that cable setup! those cables would run some serious speakers using some serious power.. Oh and yes skip the spare amp thing and bridge the amp for 1 per sub...
    Well gotta fly
    gadget
  • kpippenkpippen Posts: 551
    edited April 2007
    Gadget,

    I'm sailing again!... Thank you so much for your help!

    Kevin
  • wolfgongwolfgong Posts: 74
    This is great fun! I'm just gonna sit back and watch for the most part and learn.

    I'm trying to figure out how the amps will be used. From my crownaudio forum calculation I get:
    Each sub will require an entire amp bridged. The is just what Gadget has indicated.
    Each 125 will use one channel of a third amp.

    What I'm not sure about is what to put on the two 115i's that are in parallel. I'm sure Gadget will have an idea about that.

    I'm also wondering from running sound and fiting feedback if the 115is should be moved forward more so open mics on the stage area are not in the 'shadow'.

    Fire at will.
  • kpippenkpippen Posts: 551
    edited April 2007
    Wolfgong,

    Excellent questions!... I'm also curious to about your question of available headroom to the 115s... Their power capacity is 250 watts continuous... Since I paralleled two 115s per channel this equates to a 500 watts continuous?...as presented to the amp... According to the Crown thread you emailed me I should be looking for 800 to 1250 watts of available power if using the .8 or 1.25 rule... This amp is \"supposed\" to handle 650 watts per channel @ 4 ohms... Unless I'm missing something here...maybe I should look at bridged-mono with one amp on each channel to the 115s?...

    Gadget,...please give us your thoughts on this?..

    http://www.crownaudio.com/forums/index. ... topic=1747

    As of right now It looks like we will re-hang the 115s on Sunday...

    Gadget, I forgot to ask... When I rehang the 115s should I face the mating joint between the speakers straight outward?... I'm thinking that when these slighltly wedged shape cabs are attached together side by side...they will want to toe-out from each other...

    Thank you everyone!

    Kevin
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