How Mode Arcline works, with waveform scoped. (brief strobing)
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- Опубликовано: 8 июл 2017
- Mode Arcline is a relatively vintage lighting effect which is still available for hire from some companies, but should be installed with the full understanding that it uses a connector in a non compliant manner and could pose a significant shock risk if a grounded appliance is plugged into what appears to be a normal IEC socket. Non-standard use of connectors was rife in the early days of similar equipment and a certain grandfathering element has to be taken into account, and equipment like this only used by electrically competent people.
I fluffed the description of the output reset diode a bit. As soon as a high reset pulse is applied to the 4017 it will instantly be shunted by output 4 going low via the diode, meaning that the reset pulse only lasts as long as is needed to reset the chip to the first output (output zero).
The way the incoming pulses are filtered and then fully restored with new clean pulses on the output of each section makes the system very robust against external electrical interference. The use of four core cable for long runs between controller and tubes is to separate the power negative from the circuit negative so that the first tube in the run doesn't see rogue control glitches due to current spikes on the power causing misinterpretation of signals on the control line. The separate control negative carries no real current and will result in a cleaner 0v/control reference.
I've built the simple switched DMX interface box in a "Lego" style so that the same box can be used for other purposes in the future if required.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
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Takes me back to an Arcline system install. 4 x 80meter vertical runs on a theme park observation tower, the single sequence running from bottom to top, it looked fantastic, like a huge spark igniting the sides of the tower, old school but still very effective.
I had headphones on while watching this. And I could really heard it every time the circuit pulsed to light up. It was cool.
how is your comment 3 days old when this video was uploaded today?
Martijn Bruggers patreon viewer
published* today
You can see the strips of light across the frame too as the rolling shutter on the camera isn't quick enough to capture a whole frame.
They look like old film art artefacts, like when an old camera is rolling and you occasionally get white stripes with the static.
Glad you showed the control circuit. People seem to have forgotten logic can do these sorts of jobs. These days everyone seems to want to use a microcontroller.
Excellent. I love the older electronics designers solutions to problems, buffering and re-generating the signal at each stage is an excellent way to solve signal degradation in this very smart, well thought through circuit.
Alas now it would be done with a simple programmable chip, but this seems way more elegant and thought through.
Excellent explanation too Clive, not an easy one to walk through but you got it spot on.
Would have been interesting to see the waveforms coming out of the first strobe tube as well.
+mikeselectricstuff That's a good idea. The controller is back at PRGs warehouse though. I think it would have been near identical, with the only variation being a slight width difference in the reconstituted 32v pulse. What would have been really interesting would have been the waveform out of the last tube in a long run.
Thanks for showing us a tear-down of this device! Well impressed with the amount of time you take on breaking this (& other items) down to show us "how it works" (or goes bang) that even my dog would be able to understand. Would be nice to see the whole arcline in action. (when ready)
It is so cool seeing this old gear and the interfacing project.
thanks!
It really made me grin when I understood how the circuit works. Being able to do something like this with CMOS and transistors has some elegance to it when you compare it to microcontrollers that are thrown at every problem today (mostly for good reason though and I do it as well).
The pulse shaping 'tricks' brought back memories; Excellent stuff 🙂
Having been subscribed to this channel for quite a while now, I have learned quite a bit of interesting electronics concepts. Additionally, I've developed a feeling for when the word "gingerly" is about to be used.
for a time, I thought that 'gingerly' was a euphemism for '*guard me beard/guard me bollocks...*.'
Meters can give false readings, but the finger test never fails.
Indeed, It even works when you touch a 500v 150F Ultracapacitor.
But it only works once* Lucky we have 10 fingers.
Talfy I wanna hear and see that bang. Should destroy pretty much everything! Just the capbank would be gigantic.
fantastic vid man. I'm an audio guy, run studio and do live sound, but have very simple knowledge and experience and equipment with dmx.
love the explanation of where all our modern tech comes from. thanks once again!
They made some precautions to avoid mixing disco equipment connectors with normal main connectors: sockets work like plugs and vice-versa!
So these lamps can't be connected to standart 220 volt output (but they can be plugged in as 'power source' but they have no power of course), while output of this controller can't be connected to power some another device, but can be connected to 220 V live voltage which is disastrous for all the circuits involved...
But the biggest problem with this solution: these mains plugs with live voltage on them are very easy to touch by hand accidentally. In 'socket' one needs a screwdriver to get electric shock (fingers are thick enough to get into the socket), but these plugs can be accessed and can easily be shorted if they touch a corner of some metallic box.
Wonderfully explained Clive. I've always wondered how they did it using the 4017..now I know...it's all about the level shifting :). First class!!
This old tech is so much more interesting than all the integrated circuits you get today. They might be easier to work with but it's amazing how much thought and ingenuity went into these. Like "How can we have multiple functions and still get away with a single standard 3 wire cable"
Great to see this video Clive, I'm a big arcline enthusiast so it's very interesting to see these detailed explanations of how the logic works. I've used it for just about everything from disco stuff through band shows to simulating tracer fire going past a window for TV! I'm currently working on modifying one of my AL100s to be fully DMX controllable so that the speed can be set from the desk too. I shall make a video when i get it finished. (shameless self promotion!) If anyone needs to get hold of this stuff I have 3 controllers and about 60 tubes (mix of long and short) in good working order.
I remember drooling over arcline, not being able to afford it then. I still lust after it now ;)
Very cool and extremely thorough. Thanks Clive!
This was quite fun to see since I've been playing around with a 4017-based led chasing circuit.
.... and now you know how to make it work with dangerous voltages.
I remember installing these in the 80s and 90s in clubs all over the world . Took me back 😁
Got to love a pink cable tie!
yeah round ya knob!........oops sorry bang out of order my bad it just popped in my head bud
I love the knob made white. In WWII, they were having a lot of trouble keeping pilots from landing planes with the wheels up. They kept grounding all the pilots who did it, and they were becoming severely short of good pilots. No amount of discipline seemed to be solving the problem. Finally they discovered that the landing gear switch and the switch for the wing flaps were right next to each other and identical. During a landing, it was too easy to use the wrong switch. Changing the switches made all the difference.
Thanx fo rthe very informative video!
I have just started working with DMX lights, and after seeing this I think I need to dive deeper into the DMX controlling world and make my own circuits to control different stuff. It also seems that there are a lot of different types of DMX controlled stuff out there already. Until now I worked mostly with DMX controlled light via a Crestron control system. In one project the Crestron gets impulses from a Mac computer with Qlab via MIDI to RS232 (or send commands to the Mac). The Crestron system is there for setting the lights in different modes (MIDI controlled or manual control) and to control different other things like projectors and audio amplifiers. And now I get ideas for other things that can be controlled with the DMX interface :)
I remember building one of these from a circuit in Practical Electronics (or Wireless). Used it at school disco and as the "wimp" of the class a real eye opener for my teachers who simply refused to believe I could construct such space age equipment. I had also built the disco equipment itself - two SP25s with slip mats and a passive mixer using crystal pickups so no amp needed - really difficult!
Used to be able to get the strobe modules themselves as kits back in the day. They are indeed bright as hell.
The big DIN rail contactor can actually contain the tiny relay inside. I have opened a few. I expected giant contacts and a big coil rated for 230Vac. It actually contains a tiny relay with a 24Vdc coil, bridge and a capacitor dropper.
I think the point is that it is more reliable and repairable this way. If it fails just replace it instead of mucking around with the board, which may have been damaged.
That's right. I just wanted to mention that a big box doesn't mean big contacts :).
Although this is not recommended, I personally remove the earth pin from my oscilloscope and float its chassis. If the chassis is floating, you can connect the both the probe and the ground to any point in the circuit without damaging the scope. You just have to be careful not to touch any metal parts on the scope, since they will be live.
You should get an isolation transformer to power mains-referenced devices while you're measuring them with your oscilloscope. I built mine from an old 2 kVA 120/240V:120/240V power transformer and a few panel-mount switches. In addition to providing isolation, using a split-winding 1:1 transformer also gives the option to change the voltage, for example 120 -> 240 or 240 -> 120.
I also suggest working at an earth-free workstation. My workstation consists of a wooden table with a wooden chair on a tile floor. All devices (computer, oscilloscope, etc.) are ground-floated, so there is virtually no way to be shocked by touching any specific part of any circuit, even while using another device at the same time.
talking of lighting i noticed when up in cambridge a couple of weeks ago pulsar has closed down. in administration apparently. they made some good kit in the 80's and 90's.
No-o-o-o! Pulsar did some cool stuff, not another British name gone! :-(
Ahh, Arcline... Wonderful stuff. I once did a tent at Tribal Gathering with about 500 lengths. And a dozen Strobeflowers. Oh, and four floorcans on the stage to backlight the DJ. Those were the days... :)
Great video. I've always wondered how those tube sets worked. There were some very ingenious circuits back in the days of CMOS based disco effects.
Uh? Your comment is 3 days ago. This video was published just now.
Bas Emmen just publicly listed just now, patreon supporters get early access
Patreon supporters get to see the videos early, I believe. So it was published three days ago but only made public just now.
possibly a patreon supporter, possible perk of seeing a video earlier. or youtube stuffed up and it'll correct itself out sooner or later
Thanks Clive. Interesting to see how standards often bring better safety.
Well... Except modern training standards which are the complete opposite.
Agreed. That's why I chose the wording carefully: 'often'.
Wow, is that a blast from my past!
I don't know if anyone here will remember Pantiles club at Bagshot. It was the tea house Douglas Bader first took his future wife to. In later years it became a very popular disco club frequented by the London set. Oh my God - the crumpet. All gone now, they pulled it down and replaced it with an old peoples place. I stood and watched with some of the staff as all the old electronic kit was thrown into skips. Even the 'cage' the girls danced in went, swine would not let me have it. First place I took my future wife to 43 years ago ( yes she was one of those bits of crumpet, the best one of course ). They had different coloured strobe lights, filters I expect.
In the very early 80's I built a three channel colour organ back in high school, grade 9/10 electronics class. I just took it a couple steps further by combining the other grade 9/10 project which was a Xenon arc tube strobe light and the next year's grade 11 project of a five channel light sequencer to make something that someone I swear copied from me and brought to market called Arc-line Strobe.
I used the colour organ's circuit to get the strobes to flash at the intensity (variable brightness) of the audio input and used five of those Xenon arc tube strobe units to get chased along using the five channel sequencer also tied into the audio input to trigger a circuit to sense the beat.
It's been donkey's years since then but one of the most challenging parts of that project was getting these, rare at the time in my neck of the woods, stacked mylar capacitors in some weird rating that I figured I would require to get the Xenon tubes to cycle fast enough or at least that's how I recall it. Fun times back then!
I made a video about the arcline circuitry.
Reminded me of reverse engineering a telephone answering device in the 1970s. Another multiple voltage signaling system deciphered with discrete transistors. Nice piece of work.
Why has nobody recreated / built similar since? Arcline strobes at raves early 90s were brilliant! If somebody brought these back onto the market I think there'd be keen interest!
Can't wait to see the Tattoo on telly this year, seeing the effects you've talked about in the past has always been amusing, knowing the faults & foibles (like those umbrellas with LEDs on them that broke wires a lot), aswell as the tech details behind it all... :)
Just wish I could see the show in person one year, I just haven't the cash for the tickets, not even the ones on the left side by the castle walls... :(
Used to work in a club with LOTS of arcline in the rig, Always loved it as an effect from doing the slowly walking dots to the lightening bolt flash, This is the first time I've seen the controller in the light as I'm WAY too used to working in the dark by touch alone and remembering what all the controls did (not that most of the paint hadn't worn off anyway), Same venue had Astron 3 and Coemar Bello too (Bello is still one of my favourite old effects - Later replaced with Goldenscan HMI 1200's)
Everything was jet black back then.
Brilliant video there is enough information there to design a new arc light.
OK You are now Professor Big Clive. Great job. Also I want one and I'm not even sure why.
Thanks
Some fluorescent material (e.g. glow in the dark tape) over/under the flashtubes should make the flashes visible to the camera.
Something with a long afterglow.
Just seen this made me go and dig out my copies of the original circuit diagrams sent to me via fax in 2000 when I worked at Gate Crasher in Sheffield whilst at uni . I spent plenty of time fixing these tubes electronically the other problem was the poly carbonate smashed when one dropped the tubes. I even have the diagram for the 4 zone controller that was rare I think Spot co had them . The circuit diagrams are marked up as being drawn in 1985
Omg I loved this controller, we had it in a few bars I worked in that used Pulsar Rigi-flash 👍🏽
Loving the storm we are getting at the moment 4:15am
Nice. Love those lights. Iirc it's widely used in attraction parks.
Interesting. It was nice to see discrete components doing the logic in a way we could follow, rather than it all being done by microcontroller magic.
+Maxx B And morr repairable as a result.
interesting that they did so much with so little - xenon control module
That's a really clever and nice circuit. And you couldn't really make it better by using a PIC chp or arduino. The +-16V has lots of noise immunity, and the signalling is really simple.
About the only thing I could see doing with a micro in something like this would be to add some modes in the control box. In the individual flasher boards, I don't think anything more can be done with the discharge lamps.
Yeah, you could definitely add different modes. Reverse run, alternating, knightrider style chasing etc.
Maybe even better would be to make one from scratch using high power LEDs. You can safely hit most LEDs with about 10 times their rated current so long as the pulse is short and the duty cycle is low.
A few points:
Are you sure that the diode across the thyristor is a zener? Perhaps it may be a carefully spec'ed zener. The current in the series LC will build up to quite a high voltage looking like sin(t). The voltage on the capacitor will be falling looking like cos(t). When the voltage hits zero, the current will cause the voltage to continue to perhaps -100V. When the current finally stops, without the diode across the thyristor -100V will appear on it. With the diode, the current in the coil gets to reverse and swing back to where the thyristor again has perhaps 100V on it. In this time, the thyristor will have recovered.
You got the explanation of the logic exactly right. It did strike me as a bit odd that they used the 4017 when a 4022 would have served as well and a quad and as inverters but I'd bet they already had those parts in some other design so they stocked them.
The usual way to detect the "beat" of some music, involves rectifying the audio. low passing a bit and then sort of a high pass filter on that. You get a signal that goes positive when the sound suddenly gets louder. Is this what is done here?
Really interesting circuits, thanks
I have a bunch of tubes and the bigger mode controller in storage, I always wanted to find a way to retro fit in it to a modern show
"...proceed gingerly..." pokes charged capacitor. Lemme know if I got that wrong.
stcrussman He poked the body of the capacitor (the part with the labels on shrink-wrap-sort-of material) and not the pins. You can safely touch the body, but touching the pins of a charged high-voltage cap would be "quite unpleasant".
(I seem to remember a friend of mine who was learning to juggle, and to give himself incentive to do so carefully, he trained using charged high-voltage, low-capacity and high-volume electrolytic caps. If you catch one while the pins are pointing down, you get zapped. Simple, yet effective.)
Thank you. I can't believe your friend can still juggle effectively with balls that big.
stcrussman Am I sensing some sort of naughty sexual innuendo here? Anyway, he first tried it with bare caps, but later he asked me to insert them into bowling pins with an array of pads with alternating polarities on the lower section of the pin. Then he forgot that those were electrolytic caps, and connected one of these pins to charge in reverse. (I imagine that a bowling pin that squirts vapor and electrolyte everywhere would be a sight to behold.) In the end, I made a charging station for the pins with a really neat keying system.
stcrussman Am I sensing some sort of naughty sexual innuendo here? Anyway, he first tried it with bare caps, but later he asked me to insert them into bowling pins with an array of pads with alternating polarities on the lower section of the pin. Then he forgot that those were electrolytic caps, and connected one of these pins to charge in reverse. (I imagine that a bowling pin that squirts vapor and electrolyte everywhere would be a sight to behold.) In the end, I made a charging station for the pins with a really neat keying system.
The sound and lighting company I worked for in the 1990s used this product along with other Mode Lighting products. Lighting Controllers such as these were designed to be mounted in or near the DJ club console (lighting effects), not necessarily a standard 19" rack. During the period of the 1980 through 1990s there weren't many amateurs connecting these systems up.....so the connector used wouldn't have been a problem.
Mode Lighting is still in business though they shifted markets a while ago. www.modelighting.com/
That trick with the fusible joint on resistors was borrowed from commercial ones. The connection is tensioned outwards so should the solder melt it bends away from the resistor, breaking the cct.
4:30 its still that way with smoke machines. The "earth pin" is potentially connected to live via the solenoid pump.
Those connectors remind me of the fog machines they sell here around halloween -- they use that same "power cord" connector for the remote control but with some random pinout that would be bad if you plugged in a mains cable.
+Matthew Miller Yeah, they used to use that dodgy pinout here too, but they seem hard wired now.
I learned not to re-purpose mains connectors a long time ago.
It's not even safe to use a bit of mains cable for the 12V supply to a bit of test kit, even if it's got 4mm red and black plugs on it. Someone will always remove them and connect it to a Safebloc.
5:45 Hmm probably some of that luminescent pigment you used in your other videos behind the tubes could have made it more apparent which unit had just fired... iirc from firing photographic flash units at luminous dial clocks you get quite a pleasant and fairly rapid fade down.
would be interesting to build a dmx512 board into the main unit with motorized pots and optos across the switches for full control
I klnow this effect from years ago. This is a very sexy video and I love Big Clive's mastery of it, as if it will never die, in his loving hands. Respect.
an infrared filter and sheet of paper would likely make the tubes very visible to the camera :)
or perhaps just card stock/thick paper
Thanks BC for a non light video.
I liked this video & especially the schematics but I didn't notice exactly what were the voltages on the two Zeners in the circuit you drew? Do you remember after all this time I wonder? Thanks, Tom.
The power supply zener diodes were 16V to create a 16/32V supply.
Is that a Rifa PME271m capacitive smoke generator that I see next to the bridge rectifier?
BTW: I looked though the comments to see if someone answered you question about the NAND gates back to back. In the past I remember using this technique for a slight delay. Not sure it that is the purpose here, but the delay is predictable and repeatable.
Clive great video as always. Been dabbling with DMX and ws2812b custom light board for horror attractions, a rather more 21Century lighting technology, but the older stuff I love.
A nice enclosure too. Where do you get them from?
+Chris Evans The case is a UK Volex branded one for outdoor garden lighting use.
bigclivedotcom thanks Clive!
I've been looking for strobe circuits, i built one many years ago for our disco, i have all the components to build another one for a project, but my problem is that i want to sync one to mains, ideally it should trigger as close to the peak as possible, there used to be a test circuit for car strobes, but i can't find it, any help ?
Btw, 240v DC RMS ? or are you talking about the rms of the DC ripple ? :D
Do you have any instructions or more details on how you made the DMX unit ?
I recognize a lot of the components in the actual flashing lights - we make industrial flashing lights at work which look nearly identical inside (but they have their own timer / power supply etc inside).
I see a black market emerging here . . Pssssttt! want to see/buy my bits, . . for a quick flash? . . anyone? . . ;-)
Noticed a Riffa aka "toffy" (clear epoxy)mains bypass cap on mains diode bridge, these things have a real habit of exploding in a cloud of smoke without warning. i always cut them out before power up old gear (& replacing later with modern units). Interesting gismo's from the 80's
Very nice, Sir!!
I've got one of these which has packed up. any idea were i can get it repaired
First video that I have noticed you using a DSOX1102G. How long have you had that? What's your opinion of it so far? I know you're not a test gear review channel and there are a lot of those out there but it would be interesting to hear you say something about it and why you choose it over the common Rigol and other scopes in a future video.
I've used an Owon in the past, but the Keysight was sent to several electronic RUclipsrs as a gift. It's very slick. The software is much better at grabbing waveforms automatically than the Owon.
Free scope, nice, can't complain about that. R&S didn't give you a free RTB2004 too?
Do you remember Bulgin 8 way cables? I note you can still buy Bulgin plugs , sockets and cables but always as a male to female cable. Seems so strange now that we saw nothing wrong with having male to male cables. Up to four different channels firing off 240V rms. Even the female connectors were not well recessed. We just used to know not to touch them! As time went on I tended to cover the unused female sockets with gaffer tape, just to discourage little fingers. Also I recall that the pin-out varied between different manufactures and some used no earth at all. It was very necessary in those days to have a multi-meter and a reasonable understanding of electricity :)
Julian Pearce Arrrhhh yes I recall! Still have them out in the garage, disused for maybe 20 years....
I wonder how well you could recreate this effect with high density addressable LED strip? Having played with them a bit, they can be strobed pretty obnoxiously if you want.
I haven't seen fusible-repairable resistors (as used in the strobe units) for many years. If one of these resistors were to be reconnected using modern lead free solder, next time it overheated it would have to get even hotter before it tripped.
If a similar unit were to be designed now it would use a single microcontroller instead of all that CMOS logic.
Who had the idea to make the BS-Logo shaped like half a heart and an ice horn? :D Still fascinates me today!
I got a a Halloween strobe lamp at Spirit Halloween, which is a store that rents a building and then turns it into Halloween decor store every year near us. It fits in a standard US bulb sockets, and dirt simple inside and is probably not worth the price. It uses a neon to trigger it. It has a HUGE flash lamp in it, but only a 33μF capacitor. So I stuck a huge 300μF cap in there. It now hurts to look at the reflection on the wall through my eyelids.
I did that myself when I was young. Added a huge photography capacitor. Took much longer to charge, but was very bright when it triggered.
Clive, I think it's really time for you to get a safety transformer for your work :)
Could you take this further and control it by coupling 50hz line noise into the audio-in port?
Clive I am shocked (no pun intended) that you do not have a mains isolation transformer so you can connect the scope.
I followed your description of the circuit operation with ease.
Been wondering that for some time.
Very interesting Clive, even if I understood little,
That makes me feel better. Thanks.
Reg Pollock same boat
I'm here because my wife told me to find something useful to do.
Hey, Clive, I'm guessing you work in DMX Lighting Maintenance. I used to work at a theater controlling DMX lights (halogen with dimmer packs, moving heads, LEDs, strobes etc) and Also had to do some occasional repairs, You should take a look at more Dmx lights and desks like strobes and moving heads!
20:10 - "So it maybe takes a bit to follow through what's happening here..." *_Maybe_*??? It's more than this pharmaceutical lab analyst can understand with only one viewing. LOL Perhaps after at least 10-15 more viewings? :) Still an interesting video and it's always a pleasure listening to your voice no matter what you're talking about. Just keep up with the LED project videos as I can understand those now and have assembled a couple of my own little LED items.
Dat rolling shutter.
Installed a ton of those units in the late 80s/early 90s. They were extremely popular in strip clubs using transparent plexiglass stripper poles.
Are these what's in a tube if these are what a think a waltza I worked on had round tubes going all the way around it and at a night was best a strobe used to chase all the way around the machine
They were very popular on rides like Waltzers.
the flashes are so fast, you can even see the rolling shutter effect
Where did you get the 3 channel DMX relay board from, is it one of the random eBay ones? I've got a couple previously from Milford Instruments, but they sadly seem to have disappeared.
According to Companies House they were dissolved on 16 May 2017.
So I have 4 20w, 4ohm speakers, and a 50w, 3ohm sub. If I have an amp that has 2x15w and 1x30w outputs at 8ohms, could I use the speakers I have if I wired the 20w speakers in series?
You will get rated power in series (8 ohms) and more power parallel at 4 ohms but if the amp is really crappy it might cause distortion. Just try it out, not dangerous.
yeah.............I have a 50/50 chance of being right
You will have to make sure you get the polarity correct otherwise they will cancel each other out.
Well done!
Your a dam handy tech to have around wish you were my neighbor here in th US
Classic lighting !!
Sadly flashing xenon isn't something you see so often any more - outside from the fabulous world of disco, emergency vehicle flashers and aircraft beacons seem to have gone to LED. The cop cars actually seem alright but the ones on aircraft don't seem to have very much punch as the xenons they replaced.
there is enough info in this vid to build this with ..so that is what I am going to do
+bigclivedotcom I would be scared to use this unit with that ancient RIFA/WIMA metallized paper X2 cap on the mains rectifier. Those are notorious for going 'thermonuclear' at this age.
Not seen a schotty diode used for back EMF protection before.
Guessing this is to do with switching speed.
Are you sure you saw one here? Schottky diodes were very rare or maybe didn't even exist in that era. Maybe you were looking at a zener?
Maybe. I've only seen zener symbols with a single tail before.
oh, i can see one of the infamous "smoker" 0.01uf Rifa Caps inside that thing
Wonderful circuitry! If you can't make it with 4060 (osc/divider), 4017 (10 way Johnson counter) or 4093 (Quad Smidt NAND), it's not worth building
Hey Clive, Can you please take a look at these cheapo ultrasonic humidifiers off ebay?
Memories! :) :)
What does it mean that ac goes both ways? I understand that ac is a sine wave but I don't understand what that actually means.