PK Sound

[Ivan Beaver]

Re: PK Sound

Plus not to mention using the subs as a speaker stand pretty much was the worst idea they could've come up with. Big 'ol radiator sucking out all of the LF.



Evan

You are correct. The undamped cone movement will cause notches in the response of the working sub.

When I bring in a rig to a venue with an existing system I always ask the system tech to please turn on all the amps-and mute the DSP.

The amps will at as a "brake" on the cone movement.

Not as good as if they were not there or if there was a short on the speaker connector-but better than leaving the amps off.

 

[Kevin Maxwell]

Re: PK Sound

So, I have to say, I wasn't impressed with the system. The subs had output but did not go deep relative to the Rat Subs. They were prominent in the 60Hz range and fell off fast below the upper 30Hz range, maybe higher. The tops were weak as well. 12" 2-way boxes with a 1" driver. I'm biased, but the LD said the Rat system is much better and you can feel the low end in the floor. You also couldn't hear the vocals. Probably the lack of 2" drivers for the horns.

What was even less impressive is that the sound co. was using a pair of my subs as stands for their tops without asking when I arrived before "sound check.' I stopped by just to see what was going on for a few minutes. I left after snapping the pics. They also didn't bring a distro of any sort. I had got a text from the venue's director when they arrived telling me the sound co. wanted to use my distro. It had not been rented so the answer was no. I had pulled the donkey dick from the house sub panel the day prior to prevent unauthorized use. Good thing because these folks seem to have no qualms about using stuff without asking.

This evening, I went into town a few blocks away for a friend's bday party and stopped by the show to find that now they had grabbed my fills to use as DJ monitors without renting them. Should have locked them up. In any case, the promoter will be getting an invoice from me in the morning after I've tested them to make sure they're not blown. The venue manager has already agreed to hold the promoter's deposit until all debts with me are settled.

The LD also told me apparently the sound co. didn't bother to bring a single vocal mic either for the EDM DJs. WTF?? They had to borrow one from someone. Pretty unprofessional outfit. Beware.

I thought that the room was bigger from the way you talked about it, or is it just that it looks small in the picture?

 

[Greg Cameron]

Re: PK Sound

I thought that the room was bigger from the way you talked about it, or is it just that it looks small in the picture?

It's about 600 person max capacity room with additional viewing space from the "upper gallery" on the left. Not huge.

 

[Art Welter]

Re: PK Sound

I see on their site they have two different sub models. These must have been the "Klarity" 218, the lesser of the two. The CX model is a bit larger and uses higher power drivers. Based on what you guys have said about their subs, there's no way these could have been the ones discussed earlier.

Greg,

Correct, and the "Klowns" owning the "Kompany" that brought in the tiny PK system probably has the same association to PK as you with Rat Sound, you both purchased systems from companies that both tour with proprietary cabinets and also sell them.

Not to imply that PK is in the same class as Rat Sound, their "reputation" has been built upon tours with DJs, rather than Dave & company's work with great bands such as RHCP and hundreds of major festivals each with scores of great artists spanning the course of decades.

Put a dozen PK (or any other brand) 2x18" cabinets each powered by 4000 watts using drivers with 15mm (or more) Xmax and some serious low frequency action will ensue, that obviously did not happen at your venue.

Will be interested to hear if the "PK"ers blew anything in your fills.
Did the venue's LD say what the general crowd response was to the show?

Art

 

[Greg Cameron]

Re: PK Sound

Actually Art, I don't sell any hardware, just my services Just a long time friend of Rat and early employee back in the 80s for a bit.

I did a pink n' sweep of the fills the day after. No harm done. The promoter was emailed an invoice. The reply was that he didn't have knowledge the sound co. had taken liberties with my gear (which I find difficult to believe) and that he was looking into it. Either way I'll get paid. I don't think the venue director will allow PK back in the building for future events due their type of "professionalism." Not my call though. I haven't spoken to the LD since I stopped by during the event. The crowd was decent. It seems they could have had a better sonic experience than what they were given though. But they probably wouldn't know the difference.

 

[kristianjohnsen]

Re: PK Sound

If the venue subs are left out and are blocking viable loudspeaker positions, they can realistically be considered part of the architecture of the venue. IMO, stacking on top of them was fair game; if you were that concerned about them not being touched by others, they should have been struck. OTOH, using venue gear such as distro or fills without permission is not fair game.

I feel the same way. Hooking up electronics/electrics and using them without asking = uncool.

Using subs to stack on: We stack on/off our subs at the warehouse/in the trailer/at the show EVERY TIME they're used. If someone wants to put theirs subs on my subs at some point. Meh. Pick your battles

 

[Dick Rees]

Re: PK Sound

Plus not to mention using the subs as a speaker stand pretty much was the worst idea they could've come up with. Big 'ol radiator sucking out all of the LF.

Evan

You are correct. The undamped cone movement will cause notches in the response of the working sub.

When I bring in a rig to a venue with an existing system I always ask the system tech to please turn on all the amps-and mute the DSP.

The amps will at as a "brake" on the cone movement.

Not as good as if they were not there or if there was a short on the speaker connector-but better than leaving the amps off.

I feel the same way. Hooking up electronics/electrics and using them without asking = uncool.

Using subs to stack on: We stack on/off our subs at the warehouse/in the trailer/at the show EVERY TIME they're used. If someone wants to put theirs subs on my subs at some point. Meh. Pick your battles

La-la-la...

 

[Guy Graham]

Re: PK Sound

You are correct. The undamped cone movement will cause notches in the response of the working sub.

When I bring in a rig to a venue with an existing system I always ask the system tech to please turn on all the amps-and mute the DSP.

The amps will at as a "brake" on the cone movement.

Not as good as if they were not there or if there was a short on the speaker connector-but better than leaving the amps off.

With the undampened cabinets acting as passive radiators, is there not potential for them to also add as well as subtract, in the case of the notches described?



Sent from my GT-I8160 2

 

[Ivan Beaver]

Re: PK Sound

With the undampened cabinets acting as passive radiators, is there not potential for them to also add as well as subtract, in the case of the notches described?



Sent from my GT-I8160 2

How could they possibly add? In order to add-there has to be some kind of "active" element. That does not mean amplifiers or even speakers-but things like walls can act as horns when the loudspeaker is properly placed. "barn doors" or extension flares have been very common over the years for subs-and they are nothing but sheets of plywood-but they are placed in the proper position to help load the low freq horn.

When they subtract they are acting as a tuned chamber and basically "absorbing" at the tuned freq.

It is not like combfiltering in which you get up to 3dB addition at some freq and "complete cancellation" at other freq. Because with combfiltering you have 2 active elements.

 

[Glenn Adams]

Re: PK Sound

How could they possibly add? In order to add-there has to be some kind of "active" element. That does not mean amplifiers or even speakers-but things like walls can act as horns when the loudspeaker is properly placed. "barn doors" or extension flares have been very common over the years for subs-and they are nothing but sheets of plywood-but they are placed in the proper position to help load the low freq horn.

When they subtract they are acting as a tuned chamber and basically "absorbing" at the tuned freq.

It is not like combfiltering in which you get up to 3dB addition at some freq and "complete cancellation" at other freq. Because with combfiltering you have 2 active elements.

Also in order to be a passive, to add it would have to share the same box and have mass added to the cone to tune it. A cone in a box above a stack of subs, unshorted may be able to add, but more like 400 to 500 HZ, well above the crossover point and not at 40 to 50hz where it could do some good.

 

[Kevin Maxwell]

Re: PK Sound

It's about 600 person max capacity room with additional viewing space from the "upper gallery" on the left. Not huge.

I see it was the picture it looks much bigger in that picture.

 

[Guy Graham]

Re: PK Sound

I just thought that the unshorted enclosure would react to the resonance from the actively driven cabinet, and that longer wavelengths would be more susceptible to this (both addition and subtraction).

I.e. along with the uneven absorption via the notches described - theoretically there could also be potential sympathetic vibration from the passive cabinet, at certain frequencies related to the tuning of that cabinet and the frequencies coming from the active cabinet.

I'm happy to accept I'm wrong, thanks for the explanation!

Sent from my GT-I8160 2

 

[Art Welter]

Re: PK Sound

With the undampened cabinets acting as passive radiators, is there not potential for them to also add as well as subtract, in the case of the notches described?

......I'm happy to accept I'm wrong, thanks for the explanation!

Guy,

You were not wrong.
You can see what happens with two subs under three conditions in post #18 here:
https://soundforums.net/threads/9787-Stair-Cardioid-Subwoofer-Array
1) Green trace- 18" cabinet alone.
2) Blue trace- 18" cabinet with another along side, the input terminals shorted.
3) Purple trace- 18" cabinet with another along, the input terminals not connected (open circuit).
Of interest, the Fb/Fc (box tuning) of the horn cabinets in the link is about 35 Hz, the "suck out" is above the Fb.
As far as what happened with two bass reflex boxes with two different tunings, hard to say without measuring in the room.
It likely would be a similar effect as in the measurements in the link above, the added frontal area (barn doors) of the non-powered sub would provide gain over the entire sub range (more gain in the upper range), while frequencies somewhere around or above the Fb of the non-powered box would be attenuated.
The Rat Subs Fb (IIRC) is 28 Hz, probably a bit lower than the PK, the LD saying the PK subs did not have the LF of the Rat Subs could be due to the LF "suck out" the (un-shorted) non-powered subs.

 

[kristianjohnsen]

Re: PK Sound

La-la-la...

Your point, dear Sir?

 

[Guy Graham]

Re: PK Sound

Guy,

You were not wrong.
You can see what happens with two subs under three conditions in post #18 here:
https://soundforums.net/threads/9787-Stair-Cardioid-Subwoofer-Array
1) Green trace- 18" cabinet alone.
2) Blue trace- 18" cabinet with another along side, the input terminals shorted.
3) Purple trace- 18" cabinet with another along, the input terminals not connected (open circuit).
Of interest, the Fb/Fc (box tuning) of the horn cabinets in the link is about 35 Hz, the "suck out" is above the Fb.
As far as what happened with two bass reflex boxes with two different tunings, hard to say without measuring in the room.
It likely would be a similar effect as in the measurements in the link above, the added frontal area (barn doors) of the non-powered sub would provide gain over the entire sub range (more gain in the upper range), while frequencies somewhere around or above the Fb of the non-powered box would be attenuated.
The Rat Subs Fb (IIRC) is 28 Hz, probably a bit lower than the PK, the LD saying the PK subs did not have the LF of the Rat Subs could be due to the LF "suck out" the (un-shorted) non-powered subs.

Thanks for that Art!

It was interesting to re-read that thread again after many months. The purple trace is notably different with those two distinct dips not present in the other, much smoother lines. Am I right to understand you as stating that you expected the same measurement done with bass reflex cabinets would likely only have one dip in the curve of the equivalent measurement made with an unpowered and unshorted cabinet acting as a passive radiator, as the higher second dip in the purple line is caused by "the secondary impedance peak" that your tapped horn subs have?

You estimate that the Fb parameter of Greg's subs could have been responsible for the lack of very low sub-bass during the PK event, based on your own measured evidence that indicates a correlation with box tuning frequencies and interaction of this type. Seeing how they were used as stands, between the subs and the tops - is it likely that the frequency response of those tops could also have been affected, or do you not have sufficient information to make an educated estimate there?

I appreciate the effort and thorough answers already provided to my often technically illiterate, clumsily worded queries.

 

[Art Welter]

Re: PK Sound

Thanks for that Art!

It was interesting to re-read that thread again after many months. The purple trace is notably different with those two distinct dips not present in the other, much smoother lines.
1)Am I right to understand you as stating that you expected the same measurement done with bass reflex cabinets would likely only have one dip in the curve of the equivalent measurement made with an unpowered and unshorted cabinet acting as a passive radiator, as the higher second dip in the purple line is caused by "the secondary impedance peak" that your tapped horn subs have?

2)You estimate that the Fb parameter of Greg's subs could have been responsible for the lack of very low sub-bass during the PK event, based on your own measured evidence that indicates a correlation with box tuning frequencies and interaction of this type.

3)Seeing how they were used as stands, between the subs and the tops - is it likely that the frequency response of those tops could also have been affected, or do you not have sufficient information to make an educated estimate there?

Guy,
1) I would expect only one dip in the frequency curve of the equivalent measurement done with BR cabinets near other cabinets. That said, I would not bet much on it, as I have not specifically done that measurement. The measurements referenced were done while testing the response of the Keystone cabinets in different arrays, just threw added those tests to demonstrate both the effectiveness of a relatively small boundary increase, and problems non powered, un-shorted cabinets can cause, and to illustrate that using multiple TH does not lower the F3 as some simulation programs predict. Even multiple FLH (front loaded horns) hardly change in the low corner, but their LF level increases far more in multiples than TH. Multiple BR and TH frequency response stay pretty similar to single cabinet response, other than changes due to center to center distance cancellation and reinforcement.

2) Fb (Frequency of Box) is a resonant frequency which remains the same regardless of TS (Theile Small) loudspeaker parameters. Although there is plenty of evidence from multiple sources that non powered, un-shorted cabinets cause frequency response problems without testing on a variety of boxes with differing Fb and TS it would be impossible (for me) to predict the correlations.

3) My educated guess would be the Helmholtz resonance (Fb) would be so far below the top cabinets pass band that they would be unaffected.

The distance to any and all nearby boundaries has an effect on a loudspeakers frequency response. The distance to the sub, floor, walls and ceiling could all be estimated from the photo and put into a 3D ( 3 dimensional) speaker response simulator (I have investigated if any simulator programs have progressed from 2D to 3D yet) then the estimated crowd absorptive density could be entered, and it would puke out some answer probably as valid as me guessing their response was probably "pretty hosed".

Most DJ set up guys don't have little, if any knowledge of system/room tuning. Since the PK system operators didn't even carry a DJ vocal mic, we can probably surmise they were not carrying a measurement mic, though they might have had an iPhone app with an RTA and a SPL meter that gives completely bogus readings at levels over 105 (or is it 110?) dB. PK targets customers playing music genres that makes system tuning rather low on their priority list, usually somewhere below "score some X, make sure the promoter has provided the case(es) of booze & smokes on the rider, get the hot chick's address" etc. ;^).

Art

 

[Per Søvik]

Re: PK Sound

I feel the same way. Hooking up electronics/electrics and using them without asking = uncool.

Using subs to stack on: We stack on/off our subs at the warehouse/in the trailer/at the show EVERY TIME they're used. If someone wants to put theirs subs on my subs at some point. Meh. Pick your battles

What I find really uncool, are people filling up venues with all their crap and then moan when others move their crap to be able to use the venue and the facilities that they are actually paying for.
"Stage door left? Sorry, you can't use that because the brassband has blocked it with their timpani and percussion." Main loading dock? No, the other sound company are stacking their subs there", "Stage platforms? Yes, they are underneath the backdrops from last year's christmas play". "No, the green-room is occupied by the orchestra's chairs and instruments."

 

[Marjan Milosevic]

Re: PK Sound

Per, i as understand, in this case the gear was a sort of permanent install. So what you say is that the company that have rented their gear on a long term basis, should come and dismantle the rig every time someone want to use some other rig there? Sure, it can be done, but someone need to cover the cost for that too.

 

[Per Søvik]

Re: PK Sound

Per, i as understand, in this case the gear was a sort of permanent install. So what you say is that the company that have rented their gear on a long term basis, should come and dismantle the rig every time someone want to use some other rig there? Sure, it can be done, but someone need to cover the cost for that too.

Of course, I don't know the details here, but when you rent a venue, and given you are allowed to rent that venue without sound provided as part of the package, or there is a provision in the contract that you have to use the installed equipment and pay whoever for it, then you should be able to use that venue for the intended purpose without having to contend with constraints that seriously hamper your utilization of the venue for the purpose for which it is rented. Not being allowed to move equipment out of the way is one such constraint.

Of course, in this particular case it seems they weren't so much moving the equipment out of the way as moving it to use for their own purpose, which is a different matter.

 

[Max Warasila]

Re: PK Sound

Of course, I don't know the details here, but when you rent a venue, and given you are allowed to rent that venue without sound provided as part of the package, or there is a provision in the contract that you have to use the installed equipment and pay whoever for it, then you should be able to use that venue for the intended purpose without having to contend with constraints that seriously hamper your utilization of the venue for the purpose for which it is rented. Not being allowed to move equipment out of the way is one such constraint.

Of course, in this particular case it seems they weren't so much moving the equipment out of the way as moving it to use for their own purpose, which is a different matter.

Community theaters are the worst offenders in the category of Unmovable Shit in the Way Syndrome. I've found that when several parties are using the space without paying much more than community use prices they don't care about the other parties there that much. I can't even begin to count the number of hours I've spent moving music stands, chairs and band shells off the main stage because the orchestra just decided that they didn't have to clean up after themselves to make way for another group (one particular group was paying the full rental price for the venue... and I was the one having to explain why there were large and obtrusive pieces of plastic all over the stage). Such is life however.

Rules basically seem to be:
-If you leave stuff out and in the way, expect for it to be moved while you are away.
-Stuff is only in the way when there simply isn't another way for you to do your job while it is where it is.
-Ask the venue manager or on call staff member before moving anything that isn't yours. Plus, often times the staff are just as angry about it being where it is as you are.