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Title: RCF 8003 mk2 vs Thomann TP218
Post by: Terry Jackson 5 on April 18, 2019, 03:16:45 PM

https://www.thomann.de/gb/the_box_pro_tp218_1600_a.htm?ref=search_prv_4

https://www.thomann.de/gb/rcf_sub_8003_as_mkii.htm

Hi all the names terry,

I currently own 2 RCF 8003 mk2 and i have to say they are an amazing product, ive been eyeing up the thomann subwoofer for a while now and would appriciate any thoughts on it or owners comments.

on paper it would seem that it is slightly louder and has double the wattage of the rcf but i cant help feeling its going to be louder in reality but that is just a hunch.

the buyers reviews on thomann are all in favour and i think its no.2 in the charts for thomann.

but its a long way to ship if its a piece of junk, and doris at the post office will be none to happy when i try to ship this baby back to germany from the uk.

Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Luke Geis on April 18, 2019, 07:08:17 PM
My 2 pennies are this:

We are talking about a Dual 18" sub that should have a theoretical +3db to +6db advantage over a single 18" any day of the week. This means that the T sub is weak sauce in comparison. If you were to add another pair of RCF 8003's ( for a total of 4 ), you would easily have nearly double the output that a pair of the dual 18" T subs could provide.

To make things even more interesting, the Thomann T Sub is a Box store brand. I.E. it is a very cheaply made unit to get it into a market segment that is not actually owned, designed or even produced by the name that is on the box. While Thomann may have given the manufacturer some input as to what they wanted, they had likely nothing to do with the actual making of it other than placing their name on it.

Now for the good side of things. The Thomann T sub is VERY CHEAP!!! So those that will invest in it will get a pretty fair amount of boom for the buck. Because it is so cheap most will afford buying at least a pair if not more. Now, 136db isn't exactly petty change volume. Assuming the speaker at least performs close to the same standard that other vendors do, it will produce decent output. The caveat to that is that most dual 18" designs that are even on teh lower end of the performance scale will produce around 138db. Granted 2db is nothing to really worry about, but it is a clear indication that it is NOT up to the same level as even other affordable units are.

The math side of things. Assuming we can extract 100% of the SPL each speaker says it can make, this means that the RCF speaker is only 1db lower in SPL to that of the T sub with 2 X 18" speakers in it!!! Now if we were to get a full +6db for doubling the number of subs, this would mean that the T sub would have a total potential SPL of 142db ( 136 + 6= 142 ) if you had 2 of them. The RCF would have  141db ( 135 + 6= 141 ) if you had two of them. Now imagine if you had yet another pair of RCF 8003's!?!?! This would mean you have a total of 4 single 18" subs that are capable of producing yet another +6db in output. With 4 of the RCF speakers, you would have a theoretical peak output of 147db! That is 5db more than a pair of T subs and it would still consume the same amount of space. 5db is considerable, but there is more.

RCF is known as a reliable and credible vendor and the specs they state are pretty true and honest. That is to say that the 8003 could actually be capable of producing the peak output it states. Most vendors are not as honest and the peak numbers they state are only capable under very special or specific conditions. The T sub doesn't stand out as being the type that would actually be able to produce the output it states. While 136db is modest for a dual 18" sub, I still don't believe that it will actually produce that number.  Tit for tat right now, I feel that the RCF's would hold their own quite well against the T subs. If I really wanted more boom in teh room, I would double down on the RCF's.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Tim McCulloch on April 19, 2019, 01:47:34 PM
Watts don't make sound.  The loudspeaker rating in Watts is how much power the voice coil can dissipate as heat for a limited amount of time.

If you want more Watts, buy a resistance space heater.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Ivan Beaver on April 19, 2019, 02:31:54 PM
Watts don't make sound.  The loudspeaker rating in Watts is how much power the voice coil can dissipate as heat for a limited amount of time.

If you want more Watts, buy a resistance space heater.
Toasters are also good if you want a lot of watts in a smaller package.

Hot water heater elements are also good for dissipating lots of watts.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Mark Wilkinson on April 19, 2019, 05:19:57 PM
Toasters are also good if you want a lot of watts in a smaller package.

Hot water heater elements are also good for dissipating lots of watts.


Funny..
Me poor man's amp load ...
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Ivan Beaver on April 19, 2019, 05:54:18 PM
Funny..
Me poor man's amp load ...
It works well, AS LONG AS there is plenty of water to cover up the heaters.

It is amazing how a decent sized amp can quickly turn a hot water heater turn bright orange/red.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Terry Jackson 5 on April 19, 2019, 05:55:39 PM
My 2 pennies are this:

We are talking about a Dual 18" sub that should have a theoretical +3db to +6db advantage over a single 18" any day of the week. This means that the T sub is weak sauce in comparison. If you were to add another pair of RCF 8003's ( for a total of 4 ), you would easily have nearly double the output that a pair of the dual 18" T subs could provide.

To make things even more interesting, the Thomann T Sub is a Box store brand. I.E. it is a very cheaply made unit to get it into a market segment that is not actually owned, designed or even produced by the name that is on the box. While Thomann may have given the manufacturer some input as to what they wanted, they had likely nothing to do with the actual making of it other than placing their name on it.

Now for the good side of things. The Thomann T sub is VERY CHEAP!!! So those that will invest in it will get a pretty fair amount of boom for the buck. Because it is so cheap most will afford buying at least a pair if not more. Now, 136db isn't exactly petty change volume. Assuming the speaker at least performs close to the same standard that other vendors do, it will produce decent output. The caveat to that is that most dual 18" designs that are even on teh lower end of the performance scale will produce around 138db. Granted 2db is nothing to really worry about, but it is a clear indication that it is NOT up to the same level as even other affordable units are.

The math side of things. Assuming we can extract 100% of the SPL each speaker says it can make, this means that the RCF speaker is only 1db lower in SPL to that of the T sub with 2 X 18" speakers in it!!! Now if we were to get a full +6db for doubling the number of subs, this would mean that the T sub would have a total potential SPL of 142db ( 136 + 6= 142 ) if you had 2 of them. The RCF would have  141db ( 135 + 6= 141 ) if you had two of them. Now imagine if you had yet another pair of RCF 8003's!?!?! This would mean you have a total of 4 single 18" subs that are capable of producing yet another +6db in output. With 4 of the RCF speakers, you would have a theoretical peak output of 147db! That is 5db more than a pair of T subs and it would still consume the same amount of space. 5db is considerable, but there is more.

RCF is known as a reliable and credible vendor and the specs they state are pretty true and honest. That is to say that the 8003 could actually be capable of producing the peak output it states. Most vendors are not as honest and the peak numbers they state are only capable under very special or specific conditions. The T sub doesn't stand out as being the type that would actually be able to produce the output it states. While 136db is modest for a dual 18" sub, I still don't believe that it will actually produce that number.  Tit for tat right now, I feel that the RCF's would hold their own quite well against the T subs. If I really wanted more boom in teh room, I would double down on the RCF's.

Thanks for the in depth response i really do appriciate you taking the time. I can't afford to double down on the rcf's or i would instantly they are amazingly powerfull for a relatively light box. I guess i was trying to get the effect of 2 more rcf's with the outlay of the thomann.

I know watts arnt everything, but i started with a jbl jrx (500w) ----> yamaha dxs18 (1050w) ---------> RCF8003 (2200w) , on my particular journey more watts have indeed equaled more power.

shame i cant demo the thomann im so curious.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Luke Geis on April 19, 2019, 09:20:16 PM
We say watts don't equate to volume because there are two things that really make watts a useless measure. First and foremost, you get to a point of diminishing returns REALLY quick when it comes to watts. In order to acquire a +3db increase in output, you need double the wattage. So going from 1000 watts to 2000 watts with the same speaker should yield a +3db increase in SPL. To get another +3db you would then need 4000 watts! Now most amplifiers DO NOT have that kind of power on tap per channel and at ideal impedances ( no less than 4 ohm's ). 4000 watts for most is about the point of diminishing returns.

Next is speaker sensitivity. This is the true measure for performance. If you have two speakers and one has a sensitivity of 95db and the other has a sensitivity of 100db, the one with the higher sensitivity will always be 5db louder. This means that watt for watt, a speaker with higher sensitivity will simply produce more SPL with less needed wattage. As you can imagine, a speaker that has a +3db sensitivity advantage is already one doubling of amplifier power louder. Couple that with being able to handle more wattage ( another thing that higher end speakers tend to have going for them ), you can end up with a speaker that produces a very significant increase in output compared to lesser units.

You can factor speaker sensitivity by reverse engineering if you will. The RCF states a peak SPL of 135db with 2,200 watts. So by dividing the wattage by half and reducing spl by 3db per halving of power, you will eventually get to 1 watt. This would be the theoretical sensitivity. So 1,100 watts -3db = 132. Next is 550 watts -3db = 129 etc. etc. The math works out that the RCF 8003 has about a 101.6db sensitivity.  This is a believable number. Now the Tsub has 4,500 watts and a peak SPL of 136db. After running the numbers, the T sub has a sensitivity of about 99.5. This means the RCF is 2.1db more sensitive than the Tsub. The kick in the gut is that the Tsub has 2 speakers in it, so it should be 3db more sensitive than a single speaker right off the bat!!!! Assuming the Tsub was scaled down to a single 18" unit, it would be 6db lower in output. Since you lose 3db to loss of cone area and another 3db to halving the wattage, you lose a total of -6db. This means that at best, a single 18" of the Tsub would only have a peak SPL of 130db. Makes the RCF seem like a beast right?

Your experience with more watts equals more output also follows the scale of quality. The lowest end JBL, the mid-range Yamaha and the higher end RCF. To give you an idea, the newer JBL SRX 818 has a 1000 watt amplifier and produces 135db ( so it says anyway ). Now how did JBL get 135db of SPL with half the wattage of the RCF? It is either higher in sensitivity, or they are lying a little bit. I think it's a little bit of both, but I digress. Most speakers can't handle much beyond 4,000 watts. and most that you would be willing to afford can't get much beyond 4,000 watts per channel. This makes the 2,000 - 4,000 watt range pretty much the sweet spot for most brands and models. Less wattage = less output in general, but that is mostly because lower end units can't handle high wattage and have less sensitivity, so less wattage does equate to less output in that regard. You can still have a very low sensitivity unit that has a large amount of wattage powering it and have lower output as is evidenced by the Thomann Tsub. 
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Tim McCulloch on April 19, 2019, 10:24:03 PM
Terry, what Luke and I are telling you is that you would need 2x the Thoman subs, driven by another amplifier, to get the output of 1 RCF sub.  That's more size, weight, truck pack & storage space, and expense.  Why triple the gear to *maybe* get a 3dB increase in total output - hardly noticeable at sub frequencies.

TANSTAAFL.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Scott Holtzman on April 20, 2019, 12:12:50 AM
Thanks for the in depth response i really do appriciate you taking the time. I can't afford to double down on the rcf's or i would instantly they are amazingly powerfull for a relatively light box. I guess i was trying to get the effect of 2 more rcf's with the outlay of the thomann.

I know watts arnt everything, but i started with a jbl jrx (500w) ----> yamaha dxs18 (1050w) ---------> RCF8003 (2200w) , on my particular journey more watts have indeed equaled more power.

shame i cant demo the thomann im so curious.

Wait until you can afford it then.  These are a major step backwards in physical and sonic quality.  Mixing subs has mixed results too. 

You will be very disappointed with the results if you fo for the Thomann
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: John Schalk on April 20, 2019, 09:19:45 AM
I've been tire kicking new subs for quite a while now and the RCF 8003 Mk2 subs are near the top of my list.  Very flexible DSP settings built in.  I like the tall versus wide box size too.  In a club, you could stack a pair per side and use that to elevate your top boxes.  My suggestion is for you to network with other local sound companies until you find an RCF dealer that you can work with.  You should be able to get a better deal than the online catalog price.  Then wait until you can afford to buy more of what you already own. 
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Steve Garris on April 20, 2019, 02:39:08 PM
My 2 pennies are this:



Luke, that's such a great explanation of speakers/spl/watts that I copied it to a Word doc for future reference. Thanks!
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Ivan Beaver on April 21, 2019, 08:46:45 AM
Just to add to the "confusion" and education.

Watts has pretty much been covered, but probably MORE important is the "simple SPL" numbers.

People WANT to believe what they THINK it means, but are you sure?

Especially with subs, a simple SPL number can often be VERY VERY misleading.

Where does that number come from?

Is it from a SPL meter reading with the sub operated in the SUB (or intended range)? Or is it a more "full range" SPL reading.

MANY (most?) subs are louder (producing higher SPL) outside (higher) than the intended operating range.

So (as is often done), the "simple SPL" number is what the sub is producing from freq outside of the actual operating range.

And if the measurement is a "simple SPL meter" reading, if you had a perfectly flat response woofer, the wider the response range, the higher the meter will show.

There is one case (that I will not revel the manufacturer or model) in which a very well respected manufacturer used to give specs for subs as (20-20Khz) sensitivity.

In one particular case the SPL number was 10dB higher than it "should have been", because there was a large peak in the response around 1.8KHz.  Not exactly in the sub range, but yet the cabinet WOULD produce that SPL.  It is not usable, but doable.

So it is VERY important to know WHERE and HOW the "simple SPL" numbers are derived for the spec sheet.

Do NOT assume it is just in the sub range.

The only way to really tell is to see a freq response graph, with a calibrated SPL scale.  If you dont see that, then the numbers could be anything that the marketing dept wants them to be.

A complex question has many easy to understand WRONG answers.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Terry Jackson 5 on April 23, 2019, 05:24:11 PM
thanks again fellas for the in depth responses im going to save up for a couple more of these rcf wonder subs after reading the advice hear.

on a seperate note what do you guys think of these? they claim 136db from a speaker that costs little more than £200.

could these pass for house music events, im not trying to recreate the sydney opera house hear just boom pa boom pa boom pa..........................................

reviews on site are promising or is this just more of the same bogus claims?

https://www.thomann.de/gb/the_box_pro_dsp_115.htm#bewertung
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Luke Geis on April 23, 2019, 07:00:33 PM
Again, referring to just the math of it, for it to get that loud it would have to have a sensitivity of 104.5db!!!! There is no way in hell that a $250 speaker will have that level of performance; ABSOLUTELY NO WAY IN HELL. There are speakers that cost in the tens of thousands of dollars that will do that, but not a $250 one.

There are very few hidden gems out there and this is most certainly not one of them. While it may sound just fine and probably gets loud enough, it isn't the powerhouse it is touting itself as. My guess based on what I think the speaker is really capable of would be that it is probably at best capable of a peak SPL of 130db. That being the case, it is probably likely to have a real-world output ( actually achievable and quantifiable ) of closer to 120db which is being pretty generous actually. Now keep in mind that 120db is pretty darn loud and actually being able to produce that SPL is usually enough for most small events and low impact shows.

Live audio is one of the few industries where you do actually get what you pay for. There are obviously some bloated products that cost more than they should, but for the most part, you pay for the performance you want and it will tend to track accordingly. You really have to consider what a box brand store is trying to sell you. Typically, box brand products are aimed at tapping into the lower end markets by making products that are very cheap and having a decent margin on them. If they can sell that speaker for $250 you have to bet that it actually cost them less than $100 to produce it!!!! Scale that against even a $1,000 speaker and you can see that there is no way in hell that thing is any good in comparison. When you buy a box brand XLR cable for $15, it cost them perhaps $2 to produce it. You wouldn't believe how cheap many of these China made products are. You can buy modular 60 watt stereo Hi-Fi amplifiers with Blu-Tooth built in for $15 and that is at the retail level. Now imagine a company like I-Home or whatever, that is selling a unit similar to that for $50. You know they are getting it made for pennies on the dollar. There is no difference here with The Box Pro. It is a pennies on the dollar product sold to hit the lowest common denominator.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Caleb Dueck on April 23, 2019, 07:26:58 PM
thanks again fellas for the in depth responses im going to save up for a couple more of these rcf wonder subs after reading the advice hear.

on a seperate note what do you guys think of these? they claim 136db from a speaker that costs little more than £200.

could these pass for house music events, im not trying to recreate the sydney opera house hear just boom pa boom pa boom pa..........................................

reviews on site are promising or is this just more of the same bogus claims?

https://www.thomann.de/gb/the_box_pro_dsp_115.htm#bewertung

When it comes to subwoofers, the best is to listen to some good subs (Danley TH118XL, BC415, JTR Orbit Shifter, even the older Bassmaxx B-Zero, or LAB Sub).  Then listen to some of the better dual 18 front loaded subs (KS28, B22, RS18, etc).  With those two data points in mind, then listen to the various other lower cost subs. 

This is why I would rather have a single TH118XL (for example) rather than multiple cheap subs.  I've used the RCF 8004, the big brother to the 8003, and it's 'OK' but muddy compared to the above subs.  Once you add the cost of multiple cheap subs vs one good sub, and the total space required, and electrical current required - there's a reason why fewer high quality subs are better than more cheap subs. 
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Terry Jackson 5 on April 24, 2019, 11:17:05 AM
When it comes to subwoofers, the best is to listen to some good subs (Danley TH118XL, BC415, JTR Orbit Shifter, even the older Bassmaxx B-Zero, or LAB Sub).  Then listen to some of the better dual 18 front loaded subs (KS28, B22, RS18, etc).  With those two data points in mind, then listen to the various other lower cost subs. 

This is why I would rather have a single TH118XL (for example) rather than multiple cheap subs.  I've used the RCF 8004, the big brother to the 8003, and it's 'OK' but muddy compared to the above subs.  Once you add the cost of multiple cheap subs vs one good sub, and the total space required, and electrical current required - there's a reason why fewer high quality subs are better than more cheap subs.

the subs you mention here are in a different priced ball park compared to the 8003, i have a hard time believeing that the rcf 8004 sounds muddy even in comparison to the more expensive subs you mentioned.

Saying that i am inclined to believe you because of the amount of posts you have on this forum so i guess you must no what your talking about. I dont have any where that i could demo such subs and my return on investment would be none existent for my particular circumstances.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Terry Jackson 5 on April 24, 2019, 11:20:10 AM
Again, referring to just the math of it, for it to get that loud it would have to have a sensitivity of 104.5db!!!! There is no way in hell that a $250 speaker will have that level of performance; ABSOLUTELY NO WAY IN HELL. There are speakers that cost in the tens of thousands of dollars that will do that, but not a $250 one.

There are very few hidden gems out there and this is most certainly not one of them. While it may sound just fine and probably gets loud enough, it isn't the powerhouse it is touting itself as. My guess based on what I think the speaker is really capable of would be that it is probably at best capable of a peak SPL of 130db. That being the case, it is probably likely to have a real-world output ( actually achievable and quantifiable ) of closer to 120db which is being pretty generous actually. Now keep in mind that 120db is pretty darn loud and actually being able to produce that SPL is usually enough for most small events and low impact shows.

Live audio is one of the few industries where you do actually get what you pay for. There are obviously some bloated products that cost more than they should, but for the most part, you pay for the performance you want and it will tend to track accordingly. You really have to consider what a box brand store is trying to sell you. Typically, box brand products are aimed at tapping into the lower end markets by making products that are very cheap and having a decent margin on them. If they can sell that speaker for $250 you have to bet that it actually cost them less than $100 to produce it!!!! Scale that against even a $1,000 speaker and you can see that there is no way in hell that thing is any good in comparison. When you buy a box brand XLR cable for $15, it cost them perhaps $2 to produce it. You wouldn't believe how cheap many of these China made products are. You can buy modular 60 watt stereo Hi-Fi amplifiers with Blu-Tooth built in for $15 and that is at the retail level. Now imagine a company like I-Home or whatever, that is selling a unit similar to that for $50. You know they are getting it made for pennies on the dollar. There is no difference here with The Box Pro. It is a pennies on the dollar product sold to hit the lowest common denominator.

ill let you know how they are as i have just ordered 2, ive currently just sold 2 rcf 745a, but still have 2 jbl prx715 to side by side when they arrive, im not expecting much but they would only be for a mobile disco in high pass. stand by...........
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Ivan Beaver on April 24, 2019, 01:02:04 PM
Again, referring to just the math of it, for it to get that loud it would have to have a sensitivity of 104.5db!!!!
This is not saying anything about any of the products mentioned, but rather just a "hats off" to Luke for pointing out how to do a little bit of simple math to come up with another part of the spec.

That is a VERY GOOD exercise that most people don't do.

Use the claimed output, the wattage dB gain and then look at what the sensitivity would have to be.

Have you EVER seen a similar sub that can come close to the "back calculated" number, within the intended operating range?

If you ask yourself that question, about a lot of gear, you start to get a better understanding of how things relate to each other.

It is real easy to "back work" the numbers to get other numbers, if you take a couple of minutes to see if it makes sense.
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Mark Wilkinson on April 29, 2019, 04:32:34 PM
It works well, AS LONG AS there is plenty of water to cover up the heaters.

It is amazing how a decent sized amp can quickly turn a hot water heater turn bright orange/red.

Oh yeah!  I found that out real quick...and the biggest amp i have is a PL380...

Seeing the water heater element start glowing makes me wonder how voice coils hang in so well...
Also makes me realize how nuts it is to try to get that 'last 3dB' out of our subs...
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Tim McCulloch on April 29, 2019, 06:33:44 PM
Oh yeah!  I found that out real quick...and the biggest amp i have is a PL380...

Seeing the water heater element start glowing makes me wonder how voice coils hang in so well...
Also makes me realize how nuts it is to try to get that 'last 3dB' out of our subs...

"...the futility to try to get the 'last 3dB'.....

The question is "the last 3dB of linear output" (where a +3dB change in input voltage results in a +3dB increase in measured SPL) or "the last 3dB of power before the voice coils go all Joan of Arc."
Title: Re: RCF 8003 mk2 vs Thomann TP218
Post by: Mark Wilkinson on April 30, 2019, 05:33:30 PM
"...the futility to try to get the 'last 3dB'.....

The question is "the last 3dB of linear output" (where a +3dB change in input voltage results in a +3dB increase in measured SPL) or "the last 3dB of power before the voice coils go all Joan of Arc."

Yep, better said....futility.
What's your 'futile point' ?....I'm down to 1 db compression, past that I'm feeling in 'nutsville'  :)