Advice about a ground stacked system

Hi!

I have an old sound system composed by:

- 4 1" driver B&C DE250, with ME45 horn (90x45 dispersion)
- 4 12" B&C 12plb76, horn loaded with Ciare MT001 project (a 420 mm long Exp horn with 120-200 inlet and 405x642 outlet)
- 2 18" B&C 18tbx100, horn loaded with Ciare BT01 project (similar to the JBL 4818 but without the reflex)

Obviously I need to improve the bass section but I'm in dubt about wich way to go since the bt01 and mt001 don't crossover very well and bt01 is quite poor on lowest frequencies...so:

A. Can I use the bt01 as a kick bin (changing the driver) and build up 2 or 4 new long horn subs? Like 186 one.
B. Build up another 2 or 4 bt01 for better crossover them with mids and get a lower F3?
C. Change everything buildin up a new setup with longer horn for the bass, longer horn for the mid and adding a mid-hi section to mach the 1" drivers (or swichting them with 1,4 or 2" ones which can go deeper)
D. Use something hybrid for the bass section like MHB 46 (but I don't like very much the reflex on horns)

Any advice?

Maybe the B option is the easiest and easy to upgrade...

Thanks

A. Can I use the bt01 as a kick bin (changing the driver) and build up 2 or 4 new long horn subs? Like 186 one.

Yes

B. Build up another 2 or 4 bt01 for better crossover them with mids and get a lower F3?

No, it will be better with long horn.

C. Change everything buildin up a new setup with longer horn for the bass, longer horn for the mid and adding a mid-hi section to mach the 1" drivers (or swichting them with 1,4 or 2" ones which can go deeper) a écrit:

You will need four ways. Look at MHB-4654 a and MKB-230 MKH-230. MHB-4654 can use 18 or 21", it's a TH awith 3 meters horn, it can goes as low as long horn, the loudspeaker is in free air, so better cooled.

D. Use something hybrid for the bass section like MHB 46 (but I don't like very much the reflex on horns)

MHB-46 doesn't need kick bin. Hybrid can sound a litle colored but you can make sound them more neutral if you use a PD186 in it and make the vent 23cm long

Marc34 a écrit:

A. Can I use the bt01 as a kick bin (changing the driver) and build up 2 or 4 new long horn subs? Like 186 one.

Yes

B. Build up another 2 or 4 bt01 for better crossover them with mids and get a lower F3?

No, it will  be better with long horn.

You will need four ways. Look at MHB-4654 a and MKB-230 MKH-230. MHB-4654 can use 18 or 21", it's a TH awith 3 meters horn, it can goes as low as long horn, the loudspeaker is in free air, so better cooled.

D. Use something hybrid for the bass section like MHB 46 (but I don't like very much the reflex on horns)

MHB-46 doesn't need kick bin. Hybrid can sound a litle colored but you can make sound them more neutral if you use a PD186 in it and make the vent 23cm long

Hi Marc! First of all thanks very much for your quick reply (and also for your projects   )

This is the graph of my Bt01 with B&C 18tbx100, 2.83v/2 Pi, it's similar to the "half USB" one's but with an higher sensitivity, so maybe with a little equalization I can use it as a kick bin. I drive them with a QSC rmx4050 in bridge, so 2000w for 1 bin and a good reserve over the 1200w rms. What crossover frequencies do you suggest?

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Now i need your help about the bass section...I'm planning to build at first 2 bass bin, and then, as soon as possible another 2...

So, finally i reach a little stack of 2 bin for each side...the question is, which tipe of bass bin should I use? I'm looking for:

- Hi Spl
- Long Throw
- I don't need extreme high extension

I know that longer horns, like WSX or Invader are good for the throw thanks to the great radiance area, but is it worth it in such a little stacks?

I've looked a lot the MTH4654, it's in free air so there are some benfits (as yous said) but the radiance area is smaller than folded horns...in my mind I'm also afraid about the possibility of "destructive sum of waves" like what happen in scoops whith rear loaded horn...

The MHB 46 is awesome because (I think) it can be used also in single unit or little stacks, but as I already have kick bins is it usefull?

So, tapped? Folded? Hybrid? Lab sub? X1?  

I have already two QSC rmx 4050 for these new subs, so at the best I can deliver 2000w for each driver, can you suggest me the right one? Maybe an RCF or B&C one  

Thanks again for you help!!

I forget the 4818 horn which is pretty the same as my bt01, with a lower F3 and an outstanding sensitivity but, again...It will be in conflict with the bt01...

I've noticed that my mid (or midbass) section can go down to 160 Hz -3dB when coupled...I think this is why I didnt' like very much the crossover between MT001 and BT01!

I know that if i choose the 4654, I can easly build up in the future some MKB230 to match them and don't need the bt01 as a kick...since 18" is slower than 12"...

This is the graph of my Bt01 with B&C 18tbx100, 2.83v/2 Pi, it's similar to the "half USB" one's but with an higher sensitivity, so maybe with a little equalization I can use it as a kick bin. I drive them with a QSC rmx4050 in bridge, so 2000w for 1 bin and a good reserve over the 1200w rms. What crossover frequencies do you suggest?

Depend what are the others cabinets, but standard solution 90/180Hz

I know that longer horns, like WSX or Invader are good for the throw thanks to the great radiance area, but is it worth it in such a little stacks?

Under 4 cabinets per stack: no

I've looked a lot the MTH4654, it's in free air so there are some benfits (as yous said) but the radiance area is smaller than folded horns...in my mind I'm also afraid about the possibility of "destructive sum of waves" like what happen in scoops whith rear loaded horn...

TH are not excatly like scoops. Scoops have a rear chamber, TH no, speaker is in free air in scoop, in horn with TH. You can't compare. TH have larger bandwith so the inverted phase of cabinet will be higher than any scoop. Phase is inverted at centered frequency of 140Hz (the start is 130Hz), so no problem to cross with a kick bin. The MTH-4654 makes very clean bass, loud, and deep. Read this: : [Vous devez être inscrit et connecté pour voir ce lien]

Thanks for the explanation!! I' had never read about a lot about tapped horns, I will study more!!

So I'm going to use the MTH 4654 for 30Hz-90Hz and BT01 as kick bin for 90-180 Hz  

Can you help me with the driver? Since I can deliver 2000w to each bin, there are some 18"(or 21") alternatives, better than RCF LF18G401 so I can obtain a little more spl? Possibly RCF...or B&C...since in Italy I can find them at a good price

If you want maximum SPL and and lower distorsion, it will be better with with 21".

Compatibles 21" drivers are
B&C 21SW115
RCF LF21N451
18sound 21LW1400
18sound 21NLW9001

Marc34 a écrit:If you want maximum SPL and and lower distorsion, it will be better with with 21".

Compatibles 21" drivers are
B&C 21SW115
RCF LF21N451
18sound 21LW1400
18sound 21NLW9001

RCF LF21N451 is awesome...someone tell me that 21LW1400 is poor cause it's little Xmax and little coil...but It' way cheaper than RCF or B & C ones...since I've planned to use 2000w?

Another little request, in folded horn like 186, wsx, invader ecc...we need to limit the power delivered by the amp...so, for example, I can drive 12 wsx with only 8000w...but in my project I will dirve 4 Mth 4654 with 8000w...so, the power is the same but the max spl won't be exatly the same probably!

So, for a stack of mth is better a lot of bin with little power or less bins with plenty of power? Personally I prefer the qick response of overdrived drivers...if it can be dine with the choosed design...

RCF LF21N451 is awesome...someone tell me that 21LW1400 is poor cause it's little Xmax and little coil.

It is relative: it is not as strong as the others 21", but it can do better than a lot of 18" and it is cheap for a 21".

So, for a stack of mth is better a lot of bin with little power or less bins with plenty of power?

The better is when you can reach the required SPL without distorsion.

RCF LF21N451 is awesome...someone tell me that 21LW1400 is poor cause it's little Xmax and little coil...but It' way cheaper than RCF or B & C ones...since I've planned to use 2000w?

With the 21LW1400, you can use 1500 watts of amp, no more, or it will disrtort or will break.

With the 21LW1400, you can use 1500 watts of amp, no more, or it will disrtort or will break.

A lot of amplifier producers say that the amp must double the rms value of the speaker drived...obviously if not limited by the bin design. We know that they say you need 2x power to leave a lot of headroom to the amplifier, have quick transient response thanks to the extra power applied and also in this way the amp doesn't need to work next to clip limit...

For example QSC amp selector

Do you think it's correct? The tapped horn design suffer with overpowered driver? For example my Bt01 with 2000w at around 80HZ reach the Xmax, below this frequency it suffer...

Last question, can you post the graphs of max spl for the mth 4654 with some drivers?

Thanks again for your time spent resolving my dubts  

Power required for amp depend of 3 things:
- AES power of the speaker
- Crest factor of the music
- Mechanical limits of the speaker in the loaded cabinet

Theoretically, it is said that you can double power of the speaker. It is true with a crest factor of 6dB, but AES power is overestimated (only 2 hours of test), so you must reduce this power for long life of the speaker. Divise AES power by 1.5 and you have approximately the equivalent of IEC power (100 hours test). Then you can multiply by 2, which corresponds to 6dB peaks.

Do you think it's correct? The tapped horn design suffer with overpowered driver?

Less than a closed box electrically, no more than a BR mechanically .

Last question, can you post the graphs of max spl for the mth 4654 with some drivers?

Sorry, I haven't enough time, too many resquests.

Marc34 a écrit:

Last question, can you post the graphs of max spl for the mth 4654 with some drivers?

Sorry, I haven't enough time, too many resquests.

It doesn't matter Marc!  

Thanks for the explanation about AES power  

Now I'm going to use hornresp...are there some trick I need to know for tapped horns?

Nothing special than nothing is simple in electro acoustic.

True   I'm a mechanic engineer  

Marc,
For every driver I simulate, in the diaphragm displacement graph I can see that they reach the Xmax also with little power applied...I know it's because of TH design, but is this one of the main reason to limit the power? As the driver is in free air it's better cooled, but we cannot give it a lot of power...so at the end we are limited also in max spl due to less power...

I'm still trying to choose between B&C and RCF 21"...the RCF seems a little bit better...

I don't know how you have made sim, but it's not that it looks like simple that it is.

On the other hand, software calculate on pure RMS level, frequency by frequency. But music is not a an RMS Sine, has lot of peaks and it is not one frequency at a time, it is a complex signal, so you must interpreted numbers.

If we compare compare which is is comparable.
Example with the original WSX: it has a 1000 watts AES speaker, but cabinet is rated 600 watts AES. If you put 250 watts RMS in the sim with a 30Hz high pass 24dB/oct Butterworth, the xmax of the L18P300 will be reached at 46Hz (xmax is 10mm at 38Hz for a 7.8mm speaker), and it's just 250 watts !!!

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If you compare the MTH-4654, 750 watts input in a 18LW1400 (speaker that you think has a little xmax compared to other 21"), the maximum xmax in the sim is 9.5mm. So MTH-4654 with the worts 21" xmax speaker can handle 3 times the power of the WSX without exceeding xmax !!! Do you always think the same?

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A 2Kw speaker with a xmax of 13/14mm in the MTH-4654 can handle an amp of 3000 watts without problem.

Thanks! I' forget to sim with the 30 Hz LR !! And also to talk about rms power...With or without a compressor we have more or less crest factor in input!! I have to bear in mind that it's a mathematical approssimation  

Thanks again, I will study more and drink a liter of coffe...it was at 3 am. when i wrote!!

Yesterday I've tried for my first time Danley's th118 tapped horn...it sounds awesome!! I think that his bin have a lot of corners in the horn to increase the lenght...but I wonder how it can reach 108 db @ 2.83v in half space (he uses 4 ohm impedance   ) with a 96db driver...

Maybe because this one is designed best for high sensitivity instead of low extension and lower group delay? Or Danley simply uses a fine equalization over the crossover reaching "better-for-customers" numbers??

It seems a little more complex to build but it's not a problem for me

but I wonder how it can reach 108 db @ 2.83v in half space (he uses 4 ohm impedance Rolling Eyes ) with a 96db driver...

Like many manufacturers, numbers lie. First lie is to measure a 4 ohms drivers wirh 28.3volts à 10meters, which is equivalent to 2 watts 1m and not 1 watt 1 meter. Correct voltage is 20 volts for 10 meters.

Exactly, so they "stole" 3dB in efficency...

So, which are the benefits of limiting the number of corners during the horn expansion? I saw that on your design you preferred less corners than other TH which usually have a lot of them.

The more the corners, the less the sensitivity. Tapped Horn doesn't really works like a traditional horn, it's also a resonator.

Finally I manage to get the wood for start building 4 Mth 4654 with rcf lf18g401 (or maybe the 401n) instead of 2 with 21", so i can reach a better area coverage with four bins...In the future I can easly upgrade them with the 21"  

I noticed averybody uses the proline 3000 for 2 mth, in mono-parallel (or stereo) feeding 1100w @ 8 ohm each with the limiter set to 600w (or a little more for the 401n)...so, the questions are:

- since the proline 3000 is a Deton A One 3600, which have obviously the same specs, and they say it's rated for 3600 @ 4 ohm in bridged mode, we can assume that proline ones (rated for 2x1800 @2 ohm) con be bridged?

- is it worth it, using one Proline in bridged mode for 2 mth, giving more headroom and exactly doubling the rms/aes ratingof the driver? With the increase of THD...

I' m asking this because I have two qsc rmx 4050hd, they are quite poor with 2x850w @ 8ohm...but in bridged mode they can reach 4kw @ 4ohm, and I wonder if it's better using them in bridged mode, swapping them for prolines and run each one in dual mono, or prolines in bridge  

PS: I'm quite sure I've read everything in this forum about the prolines, I'm sorry if I forgot an important topic aout it...  

ideal power for MTH-4654 with 18g401 is 750 to 800 watts. If you want much power, you must use a 21".

Proline 3000 is ok, but don't use 2 ohms or 4 ohms bridged.

Thanks very much Marc!

My final set up will be:
- 4 MT130
- 2 MKH230 or MKH
- 4 MTH4654

The mth's will be powered by 2 Proline 3000, one each channel @ 8 ohm.

So, I actually use Behringer ultragraph pro DEQ2496, since this new setup it's a four-way I need a new crossover. I've looked obviously at t.racks and DCX ones but I'm a bit confused obout the choice.

- Single DCX unit
Since I'm planning to cross kicks under 200hz, maybe I don't need the stereo in the "last" 2 way, so I can use each of 6 DCX's output, 2 for hi, 2 for mid-hi, one summed for kick, one summed for sub? I don't like very much this solution.
I need to add a resistor before Prolines to work in safe conditions.
It has a peak limiter, it protect very well my amps but the drivers are not as protected as it would be with an rms limiter.

- Dual t.Racks
I reach a 4-way stereo, one t.Racks per side or dual 3+1 configuration.
I don't need any mod for safe operating with Prolines.
I'm limited to 7ms delay (but I can use the DEQ2496's delay line)
Its rms limiter is perfect for any "heavy-handed" Dj

Probaly the best would be DEQ2496 --> Rms limiter --> Peak limiter

What's the best choice? I would go for the dual t.racks setup but I'm afraid of clipping the Proline, lots of people tell me that its clip/limiter circuits are the weak part...

DCX is more flexible on eq, but T.Racks has advantages over RMS Limiters.

There is no great peaks in bass, so RMS limiter is not a problem. Use this calculator [Vous devez être inscrit et connecté pour voir ce lien]