Limiters Help

[Llyr Roberts 0]

My question, I'm thinking of buying 2tops 2subs 300RMS each, from class d,

I've seen this amp http://www.thomann.de/gb/t-amp_ta2400.htm which seems to the best choice so far.

It runs 2x 1200W/4 Ohm!

 

Speakers = 1400RMS

Amp = 2400RMS java script:emoticon(':ouch:', 'smid_56')

sterb188.gif

 

Giving me 1000RMS watts of head room,

Is it possible for this to work if i be careful?!

 

a limiter would limit the signal coming from a mixer making it "impossible" for the amp to blow the speakers if set up correctly? Could you recommend a limiter?

 

This would match the system perfectly, 2x 700W

http://www.thomann.de/gb/tamp_ta1400_amplifier.htm

so no need for a limiter, but I could pay £20 more and get a amp with 1000 more watts (and need a limiter) Which would you go for?!

 

All at 4ohm

 

Thanks Llyr

[TonyB 0]

Class D give conflicting information about their bass bins.

 

On the one hand they say that the crossovers are designed so that adding 8 Ohm tops, the amp will still see an impedance of 8 Ohms. In that case the bigger amp will do.

 

In their adverts they say the set up will be 4 Ohms which makes it appear more powerful in which case the lower powered amp will be better.

 

:shrug: so sorry, their confusion marketing makes it difficult to answer.

Edited June 16, 2008 by TonyB

[spinner 0]

My question, I'm thinking of buying 2tops 2subs 300RMS each, from class d,

I've seen this amp http://www.thomann.de/gb/t-amp_ta2400.htm which seems to the best choice so far.

It runs 2x 1200W/4 Ohm!

 

Speakers = 1400RMS

Amp = 2400RMS java script:emoticon(':ouch:', 'smid_56')

sterb188.gif

 

Giving me 1000RMS watts of head room,

Is it possible for this to work if i be careful?!

 

a limiter would limit the signal coming from a mixer making it "impossible" for the amp to blow the speakers if set up correctly? Could you recommend a limiter?

 

This would match the system perfectly, 2x 700W

http://www.thomann.de/gb/tamp_ta1400_amplifier.htm

so no need for a limiter, but I could pay £20 more and get a amp with 1000 more watts (and need a limiter) Which would you go for?!

 

All at 4ohm

 

Thanks Llyr

 

 

I have a T.Amp 2400. I use it with Eminence Neodymium loaded 450 watts rms bass bins ( @ 8 ohms ) with an internal crossover and FBT MaXx4 300 watts rms top cabs ( @ 8 ohms ) with the gain set at around 2 o'clock maximum.

 

It's fine and I have been complimented on the sound quality.

[Llyr Roberts 0]

Thanks TonyB, I'll ask class D to get an answer about the crossover and what will the amp detect.

 

 

I have a T.Amp 2400. I use it with Eminence Neodymium loaded 450 watts rms bass bins ( @ 8 ohms ) with an internal crossover and FBT MaXx4 300 watts rms top cabs ( @ 8 ohms ) with the gain set at around 2 o'clock maximum.

 

It's fine and I have been complimented on the sound quality.

 

 

And no need for a limiter? Do you watch you're mixers levels like a hawk?!

[spinner 0]

And no need for a limiter? Do you watch you're mixers levels like a hawk?!

 

I don't drive the mixer into the red nor do I drive the amp into clipping. There's simply no need if it's all set up correctly and used sensibly.

Edited June 17, 2008 by spinner

[Llyr Roberts 0]

I will try to be sensible then!

 

java script:emoticon(':thanks:', 'smid_69')

:thanks:

[otronics 0]

Always use a limiter regardless, but its not quite as simple as that when talking with amp powers unless you turn amp on full and limit it based on that but without some form of unit telling you how much the amp is putting out, you wouldn't know your max limit..

 

1200w - 600w per channel (2 speakers) would be OK with mixer levels peaking at 0dB and amp gains a quarter up..maybe more.

 

Risking it at high levels.

 

700w - 600w per channel would be OK.

 

I agree bigger amp could be better for the future though..maybe simply get a second amp (the 700w one), so 1 amp for tops, 1 amp for bass.

 

Do you have a spare amp at present.

[x4cs 0]

My question, I'm thinking of buying 2tops 2subs 300RMS each, from class d,

I've seen this amp http://www.thomann.de/gb/t-amp_ta2400.htm which seems to the best choice so far.

It runs 2x 1200W/4 Ohm!

 

Speakers = 1400RMS

Amp = 2400RMS java script:emoticon(':ouch:', 'smid_56')

sterb188.gif

 

Giving me 1000RMS watts of head room,

Is it possible for this to work if i be careful?!

 

a limiter would limit the signal coming from a mixer making it "impossible" for the amp to blow the speakers if set up correctly? Could you recommend a limiter?

 

This would match the system perfectly, 2x 700W

http://www.thomann.de/gb/tamp_ta1400_amplifier.htm

so no need for a limiter, but I could pay £20 more and get a amp with 1000 more watts (and need a limiter) Which would you go for?!

 

All at 4ohm

 

Thanks Llyr

 

 

you have a conflict of interests here - your calculations are dangerously wrong!

 

firstly you need to take some precautions. if the amp is spec'd to give 2400 w RMS @ 4 ohms you need to run off 4 ohms per channel. giving you 1200w RMS/chanel @ 4 ohms

 

however, you are proposing to use 2 x subs and 2 x tops rated at 300w RMS each (presumably at 4 ohms each?) which you would presumably be running 1 sub and 1 top per channel,. giving you 600w RMS per channel running at 8 ohms (resistors in series at added) so now you need to run your amp at 8 ohms to accomodate your speaker requirements per channel - running that amp at 8 ohms will give you a maximum of 650w RMS /channel @ 8 ohms.

 

so with the above considered, you are proposing to use 600w RMS/channel out of the 650w RMS/channel available. so if all your above info is correct, yes you will be able to use the 2400w RMS to run the above speakers.

 

finally, because you are proposing to run a sub and a top out of each channel you will need either a cross over capable of handling 1300w RMS of power at 8 ohms and seperating the bass & mid-top and filtering them to 4 seperate units. alternativly you will need 2 cross overs, 1 for each channel, capable of handling 650w RMS each and seperating that into 2 seperate units.

 

imho, you are running right on the limit and if you gig on a regular basis and you tend to stretch the capabilities of your amplification you run the risk of burning the amp out over time and doing damage to your other bits of gear.

 

if you want my honest opinion, id keep the seperate bass and mid-top speaker set up and run from you mixer to a cross over, seperate the bass from the rest, send the bass to one amp and run the bass bins off each channel and do the same with the mid-tops.

 

this way your amps are of less power, they are more economical and most of all your set up will not be straining on a regular basis and generally speaking your system is running at a safer level all round. this also allows you a little more fredom with the gains on your mixer.

 

i could spend a couple of hours talking you through exactly what you should be doing, but for the purposes of a forum post i hope the above helps you!

 

cheers and all the best for future gigs !!!

[spinner 0]

you have a conflict of interests here - your calculations are dangerously wrong!

 

firstly you need to take some precautions. if the amp is spec'd to give 2400 w RMS @ 4 ohms you need to run off 4 ohms per channel. giving you 1200w RMS/chanel @ 4 ohms

 

however, you are proposing to use 2 x subs and 2 x tops rated at 300w RMS each (presumably at 4 ohms each?) which you would presumably be running 1 sub and 1 top per channel,. giving you 600w RMS per channel running at 8 ohms (resistors in series at added) so now you need to run your amp at 8 ohms to accomodate your speaker requirements per channel - running that amp at 8 ohms will give you a maximum of 650w RMS /channel @ 8 ohms.

 

 

Have I missed something here?

 

I believe the Class D cabinets are rated at 8 ohms each. If each channel will have a bin, with passive crossover and mid/top connected in parallel, that will give 4 ohms on each one.

 

Just because the amp will output 1200 watts per channel at that loading, he doesn't have to use it all, surely?

[x4cs 0]

Have I missed something here?

 

I believe the Class D cabinets are rated at 8 ohms each. If each channel will have a bin, with passive crossover and mid/top connected in parallel, that will give 4 ohms on each one.

 

Just because the amp will output 1200 watts per channel at that loading, he doesn't have to use it all, surely?

 

 

i dont know the exacts of the cabs in question, i went on the presumption that they were 4 ohms - which i mentioned in my post.

 

if they are 8 ohms is does put the rest of my post into debate. but like i say, i went on the presumption of 4 ohms and gave an option considering such!

[superstardeejay 0]

We really need to ascertain whether the Class-D speakers will give us 4 or 8 ohms when connected as a top-bottom pair. Many matched sets will preserve the 8-ohms even though they're 8-ohms per cab..because the crossover in the bass cab will split the impedance rather than parallel it.

 

Whichever way it falls, a limiter is (as Otronics mentions) a good idea...almost ALL professional installations have one to protect the (often) leased or contract-maintained equipment from recalcitrant or wreckless DJ's who've never been responsible for a big PA before. (If they dont own it, who cares..right..?).

 

I say the best set-up is an over-specced amp and a limiter if necessary to protect the speakers. Not only will it sound better but will last longer. Digital compressor-limiters these days aren't expensive and work transparently (no embarrassing audio shut-downs) and are especially worth the money if you have vocalists or expect feedback or have a DJ who doesn't own the equipment.

 

 

 

[Llyr Roberts 0]

 

quote from Class D's website, (sorry speakers are 350 not 300 each)

 

"giving an amazing 1400 watts Rms at 8 Ohms 2800watts at 4 Ohms per system,"

 

Help!

 

 

plus sent this email

Hello,

I'm thinking of buying...

 

PA speakers CD15158 1400w 2x15' sub bins 2x15' tops

 

And was thinking of buying a, t-amp which runs 1200W per side at 4ohm to run it. Giving me 1000W of headroom. http://www.thomann.de/gb/t-amp_ta2400.htm

 

This is a great price for the amp and, I could buy an amp that matched perfectly, but for £20 more i can get 1000W extra to much of a bargain resist!

Would it be safe to use this amp, should i use a limiter or just be careful? Or just go for the smaller amp 2x 700?

 

The crossovers are designed so adding 8ohm tops the amp will still see a impedance of 8 Ohms, which means big amp will do but somewhere else on your website it says the set up would be 4 Ohms which means the lower powered amp 2x 700 would be better?! Which is correct?

 

Thanks Llyr

 

and got the reply

 

Hi Llyr.

No problem looked at the amp and it is a chinese copy of the C-Mark MR2650 this will run the speakers OK but remember not to put the amp into clip and just be carfull how much power you give to the speakers or you could blow them.

 

Best regards.

 

Peter.

Class D Design Ltd.

 

Does help but not give answers on everything

[TonyB 0]

I think you have found the confusing advert that I queried with Class D and never got an answer apart from "apologies for the typing error"

 

If the speakers are 350w RMS, linking them together will either give 700w at 8 Ohms each side or 700w at 4 Ohms.

 

In total it is a 1400w system at either 8 Ohms or 4 Ohms :shrug:

 

I just found the email from one for the directors at Class D. I'll email him and invite him to join the forum to help clear up the confusion smile icon

 

 

 

 

[spinner 0]

 

Hi Llyr.

No problem looked at the amp and it is a chinese copy of the C-Mark MR2650

 

 

Just to digress a bit, this is confusing me.

 

C-Mark is a Chinese company.

 

I understood that Audiohead, T. Amp and C-Mark were all the same but with different branding ( and pricing in some instances ).

[TonyB 0]

Just to digress a bit, this is confusing me.

 

C-Mark is a Chinese company.

 

I understood that Audiohead, T. Amp and C-Mark were all the same but with different branding ( and pricing in some instances ).

 

You I are probably correct. I believe Thomann re badge equipment from several different manufacturers under the "T" brand.

 

I have received a reply from Class D regarding the Ohm/wattage:

 

<Quote>

As for the confusion of the impedance of any of our 4 box systems you can

run them at 8ohms and 4ohms it's just the way you connect them up.

 

If you come out of one side of the amp and connect to the bass bin then from

the bass bin up to the top box because of the built in crossover in the bass

bin it just filters anything above 180Hz to 200Hz to the top speaker so it

does not see the other 8ohm box and the amp then only sees 8ohms.

If you come out of the amp and connect to the top speaker and connect to the

bass bin then the top speaker will see full range and by connecting to the

bass bin it will see another 8ohm box then by connecting 2 - 8ohm speakers

together the amp will then deliver 4ohms to the system.

 

So when people phone us up for advice there is 2 ways to run the system

8ohms and 4ohms because of the passive crossover in the bass bin.

 

Thanks for the invite we will take you up on it as soon as we decide who

will answer all the questions concerning Class D.

<Unquote>

 

So the class D setup can be run at either 8 Ohms or 4 Ohms depending on if you go from amp to tops or amp to bass bins first

[Llyr Roberts 0]

Thanks Everybody so far!

 

If I went from the tops to the bottoms could I be sending to much bass to the top speakers?

 

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

Now playing: Busta Rhymes feat Linkin Park - We Made It

via FoxyTunes

[TonyB 0]

Thanks Everybody so far!

 

If I went from the tops to the bottoms could I be sending to much bass to the top speakers?

 

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

Now playing: Busta Rhymes feat Linkin Park - We Made It

via FoxyTunes

 

No but the top speakers would be running full range which takes away some of the advantages of having separate bass bins and tops.

 

The lower frequencies consume a bigger proportion of the power. Having the bass bins handle the lower frequencies should result in better sounding tops. It will probably sound ok though.

 

Better solution would be to have an active crossover and separate amps for the tops and bins but you could do that later if you wanted.

[superstardeejay 0]

I understood that Audiohead, T. Amp and C-Mark were all the same but with different branding ( and pricing in some instances ).

 

The manufacturer of all these brands is Shenzhen Bao Ye Heng Industrial Development Co. They also make some DAP Audio stuff. They look like the Mackie M series.

 

The various brandings do have internal differences regarding build quality and layout but share very similar case designs.

 

 

Mackie:

http://www.djempire.co.uk/media/products/294/12040377371045807907.jpg

 

 

T-Amp

http://images4.thomann.de/pics/bdb/156557/579682_800.jpg

 

 

 

 

[spinner 0]

The manufacturer of all these brands is Shenzhen Bao Ye Heng Industrial Development Co. They also make some DAP Audio stuff. They look like the Mackie M series.

 

The various brandings do have internal differences regarding build quality and layout but share very similar case designs.

Mackie:

http://www.djempire.co.uk/media/products/294/12040377371045807907.jpg

T-Amp

http://images4.thomann.de/pics/bdb/156557/579682_800.jpg

 

 

So are they reverse engineered copies of Mackie units?

 

I remember reading somehere that the C-Mark amps are designed in USA ( by an ex-Crown designer!!?? ) but built in China. No idea of the truth about the design origins.

 

C-Mark amps are shown as their brand on the Shenzhen Bao Ye Heng website .

[superstardeejay 0]

I dont think they're reverse-engineered anything, the Chinese are quite able to engineer their own circuits! I know the Mackies are particularly well made, all surface-mount, on similar lines to their desktop mixers with similar components, pcbs, ICs etc.

 

The C-mark and descendents are all a little different inside, (and nothing like the Mackies) I do know the brand owner gets to choose from a list of features when ordering a production run eg Make of Output Transistor, type of cooling, and other subtleties that can be tweaked at relatively short notice.

 

As to why they look so similar to the established Mackies, probably the same reason that certain Pearl River lights look like the old MAD scans (the ones that MAD sued Terralec over..and won..)...I couldn't possibly comment.

 

 

 

 

 

 

[Steve_Mitchell 0]

There is a lot of Bull :poo: floating about with amps... some one will make an amp and put someones badge onand charge an extra £XXXX..

[Robster 0]

which limiters are people using? what are the things to look out for in a limiter?

[superstardeejay 0]

There are 2 main types; digital and analogue. The analogue ones have knobs on and can be tweaked to your heart's content, but are easily knocked and then your painstaiking setting-up will have to start again. And of course they're not tamperproof.

 

The digital ones usually come with added extras such as EQ (dynamic/parametric/graphic) as well as crossovers. You dont have to use all the facilities (just turn them off) and once set, they stay set. They can be password-ed for anti-tamper reasons. And they usually have more comprehensive displays to allow much easier setup.

 

Look at Alto, Phonic, DBX, BSS, Rane, Behringer, Klarktechnic, OHM and goodness knows who else. Thomann do their own T-something as well now. The most popular seem to be the Behringers (due to their price vs performance, but the choice is yours, a limiter has to do what it says on the box so you should be ok either way.)

 

A good example of a digital one is the Behringher Ultradrive Pro.

 

http://www.woodbrass.com/images/woodbrass/DCX2496_BIG.JPG

Edited June 19, 2008 by superstardeejay

[gadget 0]

 

And for the DCX2496 (digital crossover), you can get some windows software to play with to see the bits/features available - i think you need to wire it up by serial port to configure that way, but at least the windows software will show you what features are on it, to get a feel for it. 3 inputs, 6 outputs, and input A doubles up as a digital input too..

 

 

There's also the DEQ2496 by Behringer, which I have been looking at, which has optical I/O, and AES/EBU digital I/O (you can take the digital AES/EBU output straight into the DCX2496), but has added feedback destroyer, RTA/limiter/compressor, pretty much everything you'd need - it also has a mic input XLR for the measurement microphone for auto-EQ...

 

 

Oh i think all Behringer stuff now comes with a 2 year warranty now too...

 

 

David

[norty303 0]

The Ultradrive is a great unit, but IMO is easiest to use without the PC link. It has one of the best and easiest to use UI's of just about any digital controller on the market (bar maybe Lake's and the ilk, but they're another ballpark entirely!) and is exceptional value for money.

 

You need to be spending much in excess of £500 before you start to get better features of noticeably better sound quality.