AVS › AVS Forum › Audio › Receivers, Amps, and Processors › Anthem D2/D2v/AVM50/AVM50v/ARC1 tweaking guide
New Posts  All Forums:Forum Nav:

Anthem D2/D2v/AVM50/AVM50v/ARC1 tweaking guide - Page 522

post #15631 of 40880
8/20/08 at 6:07pm
Quote:
Originally Posted by CycloneMike View Post

A couple of questions regarding my current ARC curves - attached.

The movie run is on page 1 and the music on page 2 - 5000 Hz cutoff.

Is the dip at 15000 Hz due to the way ARC measures high frequencies, or possibly due to the height I am using for the microphone or is it truly a room mode? I know all my speakers are not going to roll off at the same frequency... The resulting sound does not seem to be missing the high frequencies as shown, or maybe my ears just can't tell...the sound is great!

For my music run ARC set the crossover at "full range" - why does it not use a flatter curve down to 20 Hz for the target? The curve looks the same as for the 40Hz curve for my movie setup that ARC picked for the front speakers.

I think there is a glitch in the ARC calculations for music. I went back in a did a different calculation with the cinema and set the cutoff down to 25Hz from the ARC selected 40HZ and it set the dB level higher at 20 Hz for the target than it does with full range with the music. In addition, the system will not allow me to change the target numbers for the music setting in advanced mode, only the cinema - is this correct?

Opinions please.

No, its not a room mode as they are dependent on the dimensions of your room. There are 2 kinds of audio wavelenghts in an enclosed room. Standing and travelling waves. If your shortest room dimension is 8 ft(floor to ceiling), any frequency above 140 hertz(1130/8) is a traveling wave and below it, a standing wave. 15khz. has a wavelenght of just 0.9 inch therefore it can move easily within the room.

I suspect your HF measurement is inherent on your tweeter's response. Its not that bad as 90% of the sound that we hear are bunch up between 125hz. to 4khz. anyway. I won't worry about it.

Yes, The LF target curve is also a puzzle to me. Its ovious that the measured response of good subs extend below 20 hertz and still the target and resulting calculated curve attenuates the deep end response.
Reply
Reply

Gear mentioned in this thread:

post #15632 of 40880
8/20/08 at 6:17pm
Quote:
Originally Posted by dweltman View Post

Spent a while with Oppo customer support yesterday. We went through a factory default reset and everything adjustment they could think of, but my 980 will only pass the stereo SACD signal from a 5.0 or 3.0 SACD to my D2, although it passes the multichannel signal from a 5.1 SACD appropriately. Oppo thought they fixed this issue with the last firmware upgrade, but apparently my experience indicates that it's still an issue with the D2. They had an Onkyo prepro at the factory, and could not duplicate the issue with it. They said they would contact Anthem about possible further investigation of this strange incompatibility between the 980 and the D2. Does anyone out there have an Oppo 980 with the latest firmware who can specifically check this issue (comparing SACDs with 5.1 channels vs. SACDs with 5 or 3 channels)?

I had no trouble with the 980 and the Integra. However, a Pioneer DV-58 which uses the same chipset as the 980 has the same problem you describe with the D2. I mentioned it to Anthem about a month ago but they were surprised. Supposedly, Pioneer has a fix for their player but I have not yet seen it. (BTW, an Oppo 983 has no such problems with either the D2 or the Integra.)
Reply
Reply
post #15633 of 40880
8/20/08 at 6:54pm
"I don't know what is going on with the Measured curves in your Music charts. I've not seen anything quite like that. It looks like the ARC application got confused as to the scale of those when drawing the chart. The Calculated curves look fine even in Music -- which leads me to believe the data itself is OK and this is just a charting problem."

PS - I guess i don't know how to do this quote stuff correctly.... but I think you get the idea.

Bob.

I tried the Auto detect and recalculate on a copy of the original data file, but no difference, still high raw data output in the music configuration. It almost looks like overall volume may have increased prior to starting the music config measuerements, but I am quite sure I did not change anything.

I have a couple more things i want to do in the room, then remeasure. If I still see the same difference in the music configuration data I will forward to Nick at Anthem. I went back and looked at my first measurement data and they look the same in bothe Music and cinema modes.

Thanks,
Reply
Reply
post #15634 of 40880
8/20/08 at 8:55pm
Hi Guys,

I'm installing my new ARC-1 kit (for the D1), and when I run the program, I get an error message saying that it "failed to find a valid microphone" and to check the connection.
When I connected the mic via the usb, it was recognized and loaded by the computer.
Any ideas?

Thanks,
Aaron
Reply
Reply
post #15635 of 40880
8/21/08 at 5:45am
Quote:
Originally Posted by Bob Pariseau View Post

Cool! It could just be that the re-install of XP reset the drivers.

Anyway, at least now you are set for when your ARC upgrade arrives.
--Bob

Actually, I had two laptops with Vista. Laptop #1 is a newer one and that is the one that I originally attempted the upgrade with, unsuccessfully. Laptop #2 is an older laptop that used to be XP, but I recently upgraded to Vista. Since Laptop #1 didn't work with Vista, I reinstalled XP on laptop #2. I was then able to successfully completed the upgrade.
Reply
Reply
post #15636 of 40880
8/21/08 at 5:49am
Quote:
Originally Posted by AaronG View Post

Hi Guys,

I'm installing my new ARC-1 kit (for the D1), and when I run the program, I get an error message saying that it "failed to find a valid microphone" and to check the connection.
When I connected the mic via the usb, it was recognized and loaded by the computer.
Any ideas?

Thanks,
Aaron

Per the .txt file, did you:

Before clicking on setup.exe, add your two serialized files to the folder.

If the software installer asks you to program the serial number make sure the number on the chassis sticker, the one on the mic (first six digits on cal file), and the one you're entering match. You only get one chance!! If the wrong number is entered, the unit will have to come to the factory.
Reply
Reply
post #15637 of 40880
8/21/08 at 7:39am
Thanks for the response KCWolfPck.
I installed from the included CD. When I look at the contents of the CD, the two serialized files are there.
I was not asked to enter any serial #'s.
Am I supposed to drag those files somewhere else?

Thanks,
Aaron
Reply
Reply
post #15638 of 40880
8/21/08 at 8:59am
Quote:
Originally Posted by AaronG View Post

Thanks for the response KCWolfPck.
I installed from the included CD. When I look at the contents of the CD, the two serialized files are there.
I was not asked to enter any serial #'s.
Am I supposed to drag those files somewhere else?

Thanks,
Aaron

The things to check are:
1) Windows sees the ARC usb microphone (no bad usb socket).
2) The serial files numbers should match the serial number of you D2/D1 and your microphone serial.
3) The serial files should have been copied to same folder where the ARC software was installed.
Reply
Reply
post #15639 of 40880
8/21/08 at 9:03am
Quote:
Originally Posted by Bob Pariseau View Post

There are 3 things you need to do:

1) In the Velodyne settings menu, select Preset 6 as the "Default" preset in the lower left corner of the settings. Preset 6 disables the internal Velodyne EQ processing.

2) In the same settings menu, disable the internal cross over processing in the Velodyne. Go to the crossover frequency setting in the upper left of the settings page, Select that, and then hit Reset on the remote. All of the crossover related entries should now change to NA indicating the internal crossover is turned off. [You may need to UNLOCK the "Setup" column of entries to do this.]

3) Adjust the volume of the Velodyne. With Setup / Speaker Calibration / Noise Level set to measure roughly 75dB SPL in the Anthem, and with the subwoofer volume trim line in that menu set to 0dB, adjust the volume in the Velodyne settings menu page so that it too produces roughly 75dB SPL.

When you have made those three adjustments on the Velodyne's settings menu page, Exit that page and be sure to Save your settings. This should return you to the main Velodyne screen which will now show that it is on Preset 6 with the volume you just set. Be sure to make the default Preset choice and the volume adjustment in the menu page like this (rather than on the main Velodyne front page) so that this Preset and volume is used automatically each time the Velodyne powers up.

[Double check that the Velodyne's volume setting still produces 75dB SPL just to be sure. If not, go back into the Velodyne's settings menu and make the volume change for Preset 6 in there. Exit and Save results as before.]

Preset 6, by factory default, also sets the servo setting in the Velodyne all the way up to the max value of 8 (Musical). If you have changed this in the past, my recommendation would be to set it back to 8. Again this is done on the settings menu page.
--Bob

Thank you Bob. I will save your response in a safe place and will apply the instructions once I have ARC installed in my AVM-50. I will keep you posted.

Thanks again.
Reply
Reply
post #15640 of 40880
8/21/08 at 9:16am
Newbies! Read the ARC links in the first post of this thread!

Levesque has moved the collection of ARC related links I posted into the collection of links in the first post of this thread.

Since ARC is new and we are all still learning, and since many folks have posted good, fundamental questions about the magic that is ARC, that list is a lot longer than the other topics collected there -- at least for now. But most of the posts linked to are quite short -- kind of a collection of the Frequently Asked Questions.

I strongly recommend that new ARC users peruse that collection of links. It is by far the fastest way I know of for you to get up to speed on what we know about ARC and what we think is "best practice" for using it to get the best results. All of my tutorial posts since ARC V1.2.2 came out are also included in that list.

Happy ARCing, all!
--Bob
Reply
Reply
post #15641 of 40880
8/21/08 at 9:19am
Quote:
Originally Posted by Bob Pariseau View Post

J. Fricano,
It occurs to me that your unusual setup for sub connection may also be a factor in ARC seeing an uncommonly low Room Gain in your room. I have to think about this some more, but if you *DO* try the experiment of just using the subwoofer output from the D2, check out what happens to Room Gain and let us know if you get a different number back.
--Bob

Hello Bob, I took your advice and disconnected the "High Level Inputs" to the REL and remeasured and used the 12K limits as per your suggestion. The bass is MUCH improved, deeper and clearer and the highs are more natural sounding.Watched "Casino Royale" and WOW, what a difference. It never sounded this good. Tried some music and that too sounds good. The room gain increased from 2.1... to 2.578320(Movie) and from 2.257... to 2.352219(Music). If it were not for your curiosity regarding my ARC graphs and the high bass energy, the REL set up would not have been discussed and the suggestion to remove the high level input would not have been considered. I would never have been able to realize the true potential of this software and I am truly grateful for your input!! Here are my current graphs for the 12K setting;
LL
LL
Reply
Reply
post #15642 of 40880
8/21/08 at 9:19am
Thanks tranle,

Where do I look to see if the serial files were copied?

Aaron
Reply
Reply
post #15643 of 40880
8/21/08 at 9:32am
Quote:
Originally Posted by AaronG View Post

Hi Guys,

I'm installing my new ARC-1 kit (for the D1), and when I run the program, I get an error message saying that it "failed to find a valid microphone" and to check the connection.
When I connected the mic via the usb, it was recognized and loaded by the computer.
Any ideas?

Thanks,
Aaron

Are you running Windows XP or Windows Vista? Older stuff such as Windows 2000 lacks the audio input feature that ARC uses to see the microphone. If you are running Windows XP or Windows Vista and did a limited install (choosing to have only some components installed), then the audio stuff might not be in there. You can correct that after the fact without losing your current Windows setup: Use your Windows install disc and add components, selecting any audio media related stuff that you didn't install the first time.

The ARC application asks the ARC mic to identify itself. It gets something back that says, "I am an ARC microphone". It is possible the ARC mic is broken and the USB connection is getting setup but it isn't responding when asked to identify itself. If the mic itself is broken only Anthem tech support can help you.

But it might also be your USB connection being flaky. Are you using the cable that Anthem provided -- with no extensions? If you are connected to the computer through something like a USB hub, try directly connecting to the computer. Do you have any other USB devices connected? Try removing other USB devices while doing ARC Measurements.

Go into Device Manager (in My Computer > Properties) and see if it is showing any complaints for any of your hardware. Look in the USB portion of that list and also any audio device portions. If your computer has a built-in microphone, you may need to temporarily turn that off. The computer may be telling ARC that only the built-in microphone is working.

That's about all I can think of. If none of that helps you'd best give Anthem tech support a call.
--Bob
Reply
Reply
post #15644 of 40880
8/21/08 at 9:38am
Quote:
Originally Posted by AaronG View Post

Thanks tranle,

Where do I look to see if the serial files were copied?

Aaron

My Computer > Drive C > Program Files > Anthem

Look for the ARC application itself in there. In that same folder you should have the two licensing and calibration files which have file names made up of the serial number of your Anthem and the serial number of your ARC microphone.
--Bob
Reply
Reply
post #15645 of 40880
8/21/08 at 9:50am
Quote:
Originally Posted by J. FRICANO View Post

Hello Bob, I took your advice and disconnected the "High Level Inputs" to the REL and remeasured and used the 12K limits as per your suggestion. The bass is MUCH improved, deeper and clearer and the highs are more natural sounding.Watched "Casino Royale" and WOW, what a difference. It never sounded this good. Tried some music and that too sounds good. The room gain increased from 2.1... to 2.578320(Movie) and from 2.257... to 2.352219(Music). If it were not for your curiosity regarding my ARC graphs and the high bass energy, the REL set up would not have been discussed and the suggestion to remove the high level input would not have been considered. I would never have been able to realize the true potential of this software and I am truly grateful for your input!! Here are my current graphs for the 12K setting;

That's great! Your curves look much improved to me, too. I find it fascinating that altering the feed to your subs increased the Room Gain like this. I think that might have to do with phasing differences between the two separate feeds. Your Room Gain is still lower than many are reporting here, but the curves look good, and of course the most important thing is how it actually SOUNDS.

Anyway, I think we've found a home for another batch of these:



--Bob
Reply
Reply
post #15646 of 40880
8/21/08 at 9:54am
Hi Bob,

I'm running windows 2000 (it was the closest computer to my setup with the least # of peripherals).
Is there anything I can do with 2000 or should I just bring down a different computer?

Thanks!
Reply
Reply
post #15647 of 40880
8/21/08 at 10:00am
Quote:
Originally Posted by dweltman View Post

Spent a while with Oppo customer support yesterday. We went through a factory default reset and everything adjustment they could think of, but my 980 will only pass the stereo SACD signal from a 5.0 or 3.0 SACD to my D2, although it passes the multichannel signal from a 5.1 SACD appropriately. Oppo thought they fixed this issue with the last firmware upgrade, but apparently my experience indicates that it's still an issue with the D2. They had an Onkyo prepro at the factory, and could not duplicate the issue with it. They said they would contact Anthem about possible further investigation of this strange incompatibility between the 980 and the D2. Does anyone out there have an Oppo 980 with the latest firmware who can specifically check this issue (comparing SACDs with 5.1 channels vs. SACDs with 5 or 3 channels)?

Thanks for following up on this. Please do give Anthem a call as well and alert them that they should be hearing from Oppo. Based on some of the other reports here, this may be a flaky part of the handshake -- working for some people and not for others.

Anthem is working on software with new HDMI drivers right now -- slated for the V1.34 release. That won't change the limits of what the Anthems can accept, but if there's something better the Anthems could be doing during the handshake to avoid confusing some players like this, now would be a great time to nail that down.
--Bob
Reply
Reply
post #15648 of 40880
8/21/08 at 10:04am
Quote:
Originally Posted by AaronG View Post

Hi Bob,

I'm running windows 2000 (it was the closest computer to my setup with the least # of peripherals).
Is there anything I can do with 2000 or should I just bring down a different computer?

Thanks!

You can use ARC on Windows 2000 to view files, do Calculations with different Targets, and even do Uploads. You just can't use it to do Measurements.

The audio input framework used by the ARC application to capture data from the ARC microphone doesn't exist for Windows 2000.

You'll need to use a different computer or, if this computer supports it, change the OS to XP or Vista.
--bob
Reply
Reply
post #15649 of 40880
8/21/08 at 10:11am
I can borrow a laptop that's running Vista.
Is there anything I need to watch out for with Vista?
Also, is there any problem with starting over with a different computer (or does something from ARC get married to the computer)?

Thanks again,
Aaron
Reply
Reply
post #15650 of 40880
8/21/08 at 10:25am
Quote:
Originally Posted by AaronG View Post

I can borrow a laptop that's running Vista.
Is there anything I need to watch out for with Vista?
Also, is there any problem with starting over with a different computer (or does something from ARC get married to the computer)?

Thanks again,
Aaron

There's no problem starting over with a different computer. Just do the ARC install on the new computer the way you did it the first time.

There are lots of things to watch out for with Vista (I'm a Mac person, so I'm biased), but none of them are specific to ARC.

If you are planning on using a USB to serial adapter to connect to the Anthem, then make sure you get the latest drivers from the adapter maker's web site for your version of OS. If you are CHANGING from one adapter to a newer one, I suggest you tell Vista to uninstall the drivers for the old one before you install the newer one. Folks here seem to be having the best luck with the Keyspan USA-19HS adapter.

Keep in mind that you may want to run ARC multiple times as you learn more or change things in your room or speaker setup. There will also likely be ARC software upgrades as time goes on. So if you are using a borrowed computer, consider whether you will have access to it to re-run things when you want to.
--Bob
Reply
Reply
post #15651 of 40880
8/21/08 at 10:31am
Thanks again for your help!
Reply
Reply
post #15652 of 40880
8/21/08 at 10:42am
Originally,using a D-2, Paradigm S100, CC590, Servo-15, ADPs and S-20s got xovers of front 40, center 160, sub 45, side 115 and rear 55
Then with AVM-50, ARC upgrade AND new S100s and S-15 (and replaced Lexicon LX-7 with Anthem 5 and 2 channel), then got
F 45, c 60, and sub 120, (sides and rears stayed same throughout)
Thought this might change with break-in. After 2 wks of 24 hr use got
F 45, c 60, sub 65.
What do any of you think?
tjg
Reply
Reply
post #15653 of 40880
8/21/08 at 10:57am
Quote:
Originally Posted by TJG55 View Post

Originally,using a D-2, Paradigm S100, CC590, Servo-15, ADPs and S-20s got xovers of front 40, center 160, sub 45, side 115 and rear 55
Then with AVM-50, ARC upgrade AND new S100s and S-15 (and replaced Lexicon LX-7 with Anthem 5 and 2 channel), then got
F 45, c 60, and sub 120, (sides and rears stayed same throughout)
Thought this might change with break-in. After 2 wks of 24 hr use got
F 45, c 60, sub 65.
What do any of you think?
tjg

It's hard to tell just from the list of crossover numbers but I'd be worried that your sub crossover is too low -- that you are losing some LFE content both in the original D2 setup and in the latest AVM-50 measurements. The latest sub crossover at 65Hz is at the low end of what I'd be comfortable with and the original D2 sub crossover of 45Hz is too low.

From what we've seen here, ARC uses low crossovers for the sub in two cases: (1) The internal crossover inside the subwoofer has been left on by mistake, and (2) there is a nasty room dip in the normal crossover range that ARC sees in the sub response and is trying to avoid. Either of these represent situations that ought to be corrected (and then re-Measure).

The charts would show more info.

The big difference between your 2 AVM-50 measurements may represent that your stuff was on the edge of two possible solutions and the changes due to speaker break-in, or just due to subtle Measurement differences, caused ARC to jump over to the low crossover solution the second time.

I take it you are using ARC V1.2.5 for all of this right? If you are using the ARC V1.2.6 "test" version, be aware that it was withdrawn -- it has problems.
--Bob
Reply
Reply
post #15654 of 40880
8/21/08 at 11:07am
B
Don't think I was losing LFE info as LFE bypass was engaged. Using correct version software. System setup was correct in all situations. will try to post graphs later, on different computer for now.
tjg
Reply
Reply
post #15655 of 40880
8/21/08 at 11:12am
Quote:
Originally Posted by AV-NUT-99 View Post

PS - I guess i don't know how to do this quote stuff correctly.... but I think you get the idea.

If you want to Quote part or all of someone's message in your reply, just click on the "Quote" button at the lower right of that person's message.

You will be presented with a text entry window that is pre-loaded with the text of the other person's message -- surrounded by "Quote" tags at either end. You can edit the Quoted text the same way you edit any new text you are typing in -- for example to cut the Quoted part down to a smaller portion as I did when quoting you above. Just remember that you need to leave the Quote tags (the stuff in square brackets) at BOTH ends for the Quote to work right.

Click on Preview Post to see if it is working the way you intended, and if you like what you see you can then click on Submit Reply.
--Bob
Reply
Reply
post #15656 of 40880
8/21/08 at 11:13am
Quote:
Originally Posted by TJG55 View Post

B
Don't think I was losing LFE info as LFE bypass was engaged. Using correct version software. System setup was correct in all situations. will try to post graphs later, on different computer for now.
tjg

Did YOU turn on LFE Bypass or did ARC do that for you?

I'm not quite sure what the interaction is between LFE Bypass and ARC's processing -- e.g., whether the ARC room correction stuff gets applied to the higher frequencies sent to the sub due to that Bypass.

I've got it on my list to ask Nick when he gets back from vacation.
--Bob
Reply
Reply
post #15657 of 40880
8/21/08 at 11:20am
I don't think my set-up is unique in this respect, but I've been unable to find in this thread what people are doing for mic placements when they have no actual "center" seat.

I have a 4 seat theater couch that has two recliners in the middle, flanked by 2 wedges, flanked by 2 end recliners. I am usually sitting in the left of the two middle chairs.

How I envisioned the mic placements would be to do the 1st one directly in the middle, then the remaining four and the actual 4 seating positions. However, my main concern with this practice would be that mic position 1 would be too close to mic positions 2 & 3.

How have others done/would you do given my seating:

Reply
Reply
post #15658 of 40880
8/21/08 at 11:35am
I always defeat the LFE xover, would rather have the S100s got down to 40hz range and keep sub as low as possible maintaining proper integration.
tjg
Reply
Reply
post #15659 of 40880
8/21/08 at 11:40am
Quote:
Originally Posted by KCWolfPck View Post

I don't think my set-up is unique in this respect, but I've been unable to find in this thread what people are doing for mic placements when they have no actual "center" seat.

I have a 4 seat theater couch that has two recliners in the middle, flanked by 2 wedges, flanked by 2 end recliners. I am usually sitting in the left of the two middle chairs.

How I envisioned the mic placements would be to do the 1st one directly in the middle, then the remaining four and the actual 4 seating positions. However, my main concern with this practice would be that mic position 1 would be too close to mic positions 2 & 3.

Keep in mind that the mic positions don't actually have to reflect seating positions. You are sampling the ROOM in the vicinity of the seating positions.

The trickiest thing about your setup is that it appears the far seat in the picture is up against the wall.

What I'd recommend is that you do mic #1 in the dead center. Then #2 and #3 over the wedges or just outwards of those (plan on 30" spacing). Then #4 and #5 over or just outbound of the outermost chair arms (still about 30" spacing on the straight line to the #2 and #3 positions). I think #4 and #5 ought to be closer to the screen than the other three to keep from being too close to your Surrounds on the wall -- perhaps towards the front edge of the seat cushion.

But if that far seat is really up against the wall then the #4 and #5 positions are tricky. You don't want one up against the wall or that fireplace. So swing the position back in so that it is more in front of those outer two seats and still 30" or so from #2 and #3.

Anyway, that's how I'd do it.
--Bob
Reply
Reply
post #15660 of 40880
8/21/08 at 11:50am
Quote:
Originally Posted by TJG55 View Post

I always defeat the LFE xover, would rather have the S100s got down to 40hz range and keep sub as low as possible maintaining proper integration.
tjg

Well we'll need to find out from Anthem just how that works when ARC is in use. ARC might ignore that Bypass completely, or do something more complicated with it. I just don't know.

But I'd be concerned that you might be getting no benefit from ARC room correction of the higher LFE frequencies -- which is a pretty crucial part of the Room Correction puzzle.

Keep in mind that there's no reason why the crossovers need be the same for the front speakers and the subwoofer. ARC handles overlaps in those for you just fine. Bass energy coming in on the main channels will go to the main speakers down to the crossover. A higher sub crossover doesn't change that so there's no integration issue on that front.

But with a higher sub crossover, the LFE bass energy gets to the sub without attenuation -- and ARC applies Room Correction as well. What I fear is that a low sub crossover but with LFE Bypass turned on may be restricting your ARC correction on the subwoofer only to the lowest frequencies.

------------------------------------------

I take it you are leaving LFE Bypass on while doing the Measurements, correct? I don't know that we've had any reports yet from folks comparing Measurement with LFE Bypass ON and OFF. I'll be curious to find out how ARC handles that.

===================================

ETA: OK, I sent an email to Nick on this. I'm not sure when he's back from vacation. If it's going to be a while, Piero may handle it with the ARC engineers. I'll let you know what I hear back.
--Bob
Reply
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Receivers, Amps, and Processors

Gear mentioned in this thread:

AVS › AVS Forum › Audio › Receivers, Amps, and Processors › Anthem D2/D2v/AVM50/AVM50v/ARC1 tweaking guide