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How much room you got behind your screen to the back wall Beast? Just curious in case I come up that way again.

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How much room you got behind your screen to the back wall Beast? Just curious in case I come up that way again.

 

Josh, if you make up this way again let me know and I'll be sure to clear my schedule and be there!  B)

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How much room you got behind your screen to the back wall Beast? Just curious in case I come up that way again.

 

 

Little shy of 4 feet to the back wall, so I can squeeze quite a few things back there if needed :D

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Always surprises me how little bracing some of the car audio guys have in their boxes. Makes me want a CNC really bad though.

 

I'm really happy with these drivers. I've been watching some movies on the big rig over the holidays. Nothing has come close to making the drivers sweat so far. Ran Olympus has Fallen, Oblivion and John Wick over the holidays. I had OHF set to REF and pushed the subs to +4 over and it was nothing for them. Probably run EOT and WOTW at stupid levels soon but I need the house to myself.

 

I also removed the DCX's from the system and switched to the DSP in the K20's for the bass. That got me a bit less signal chain roll off. Had to completely redo my gain staging though but without the DCX's in the loop it is now much less complicated. The T3's require less overall signal manipulation compared to the high inductance, high qtc sealed alignment with the XXX's and have way better top end sensitivity and extension. Thermal handling and overall efficiency are much better as well. I can't really say it sounds a whole lot different but it does seem like these changes resulted in a much better upper bass range through the crossover region. It definitely seems like there is a better sense of attack and punch on kick drums and sharp upper bass transients when the system is cranked up. Could just be placebo but I'd like to think all of those small changes added up. If I had to guess I'd say that the XXX's were compressing a bit on the top end due to quite a bit of power being applied to the coils in that range after equalization. The T3's are probably using 1/3 to 1/4 the power.

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What EQ curve did you end up with for what MLP response?

 

Post #17 has a before and after...It used to be easy to post up a measured electrical signal after EQ when I used the DCX's not so easy after the amps. I'll see if I can whip something up. Basically a slight 2dB wide band boost centered at 20Hz and a sharp cut near 43Hz for the peak and a little bit of wider band cutting of a couple dB near 60-90Hz. I have been lazy over the holidays and haven't been motivated to tweak it any more yet.

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Always surprises me how little bracing some of the car audio guys have in their boxes. Makes me want a CNC really bad though.

 

I'm really happy with these drivers. I've been watching some movies on the big rig over the holidays. Nothing has come close to making the drivers sweat so far. Ran Olympus has Fallen, Oblivion and John Wick over the holidays. I had OHF set to REF and pushed the subs to +4 over and it was nothing for them. Probably run EOT and WOTW at stupid levels soon but I need the house to myself.

 

I also removed the DCX's from the system and switched to the DSP in the K20's for the bass. That got me a bit less signal chain roll off. Had to completely redo my gain staging though but without the DCX's in the loop it is now much less complicated. The T3's require less overall signal manipulation compared to the high inductance, high qtc sealed alignment with the XXX's and have way better top end sensitivity and extension. Thermal handling and overall efficiency are much better as well. I can't really say it sounds a whole lot different but it does seem like these changes resulted in a much better upper bass range through the crossover region. It definitely seems like there is a better sense of attack and punch on kick drums and sharp upper bass transients when the system is cranked up. Could just be placebo but I'd like to think all of those small changes added up. If I had to guess I'd say that the XXX's were compressing a bit on the top end due to quite a bit of power being applied to the coils in that range after equalization. The T3's are probably using 1/3 to 1/4 the power.

 

 

I felt the same with my old RE's. The top end sensitivity is rough on those bad boys to say the least. I had to pair them with the JBL4648's to really get to an overall happy place. 

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Couple of things that were asked for earlier in the thread.

 

Close mic of the 19 versus a 2m GP measurement. In general close mic exhibits slight top end roll off and slight increase in LF. Hinge point seems to be near 50-70Hz somewhere. Also if more data is needed on this effect in particular I have probably 20 sets of close mic FR directly comparable with outdoor GP. I've already posted a few of the Othorn with different drivers. All of my data on it comes from a few sealed cabs and one tapped horn. Close mics are taken inside my garage. Different baffle sizes may have a large effect.

 

 

post-5-0-26629500-1457126319_thumb.jpg

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There was some question of why I chose this driver to replace the XXX's and how its extremely strong motor and over-damped response with a rising top end translate into a system design versus a more traditional driver. I'll attempt to explain part of my thought process here. Let's start with the sensitivity of the (4ohm) XXX drivers at 2 volts and compare it to the response of the (2ohm) T3 19 drivers at 1.4volts in the same cabinet.

 

We can see that the 19 has much higher top end sensitivity but the XXX has much greater mid-band sensitivity. The 19 is operating with a low qtc in the sealed test box to the point that it is very over damped. The XXX on the other hand is in a box much smaller than optimum in the same cabinet. This shows up in the low end response of both systems with the 19 exhibiting a much shallower roll off and the XXX having one that is steeper than 12dB octave from 10-20Hz. This ends up giving the 19 an advantage in sensitivity in the deep bass.

 

post-5-0-45963700-1457127828_thumb.jpg

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This is the in room response of both systems measured at the main head rest with no processing and only the subs playing.

It is easy to see that my room has significant gain below 20Hz (estimated gain profile was shown earlier in this thread)and has a major issue at the seating position at 45Hz and others at about 90Hz and 115Hz. The peaking response of the XXX related to the small air volume and also inductance effects, only makes the peak near 45Hz that much worse due to the positioning of the main seating near mid room. Additionally the sharp nulls above 100Hz react negatively with the very low sensitivity in that region. The rising but smooth response of the 19 matches up better with the particular room acoustics and seating position to result in a much better starting point.  The same room induced issues are still present but are less severe due to the much different response shape. Less overall signal manipulation will be required to achieve a flat response at the seats. Note that the two responses are scaled to the same sensitivity relative to each other as measured outdoors.

 

 

post-5-0-09322500-1457128495_thumb.jpg

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Attached here is the response of each after using EQ to achieve a flat response at the main 3 listening positions. The end result of both is quite close. Being within about a 6dB window from 6-100Hz. Note that the XXX system was using a DCX2496 for EQ at the time of this measurement and it contributes to a steeper roll off below 10Hz. It is no longer used since the EQ has been moved into the amplifiers.

 

post-5-0-90871300-1457128838_thumb.jpg

 

 

Here we can look at the measured electrical signal shaping used to get both to the same final response. It is quite different.

The XXX's required a massive amount of boosting to get the upper bass range back in line with the 20-40Hz range and also some boosting below 20Hz. The 19's also require a large amount of signal shaping but the net effect is much less severe than with the XXX's. The only frequency range where the 19's require extra boost to match the sensitivity of the XXX's is from 20-45Hz. The XXX's require more in the deep bass and a huge amount more above 60Hz. Both have a 120Hz LPF in line.

 

post-5-0-76175600-1457128826_thumb.jpg

 

Now some would think wait...20-45Hz is pretty much the meat of the bass range especially for HT and the 19's are requiring more relative signal in that range. That would be correct but very deceiving. Sensitivity is not efficiency and the 19's due to the huge motor force are much more efficient drivers than the XXX. Let's look at the impedance curve. Look where the impedance peak is and the impedance is highest. Right at 32Hz and from 20-50Hz. This is where the system is at highest efficiency and requires little current or power from the amplifiers. The XXX's also have the impedance peak right near 30Hz since both are in the same enclosure. the result is that yes the 19 is not as voltage sensitive over that range but when actual conversion efficiency is considered it is more efficient overall. The only range that the 19's require more signal boost than the XXX's is right in the range where the system is most efficient and the load on the amplifier is relatively modest to begin with. The sum total is that the 19's are much easier to drive than the XXX's with virtually any content but especially with loud upper bass in the Xo region and with large wide band effects.

 

post-5-0-99192500-1457129572_thumb.jpg

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This is awesome stuff!  Every one of your plots show superior in-room results, compared to the XXX woofers.  Congrats!

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This is awesome stuff!  Every one of your plots show superior in-room results, compared to the XXX woofers.  Congrats!

It's almost like there was some prior planning or thought process behind it??? Nah...Thatd be crazy. What luck!

 

 

Scott,

I think I'm done with the HT bass system if that says anything. After I finish the big project Ive got going it'll be time for new mains and CC, surrounds, treatments etc. maybe a riser? I'd rather not but I have been giving it some thought.

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What size box is the XXX in?

Same cab for both drivers. Same airspace as the box they were both tested in GP or close enough it don't matter. 4.5ft.

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If you're focused on low end efficiency, the XXXs need about 5 times that box from what I recall.

 

There are 2 ways to flatten a naked response; 1) boost the roll off and 2) pull down the top end.

 

If you choose the latter, you have to bump the master, increasing noise.

 

The XXXs kick the snot outta the RFs. The caveat is that they require a huge box and a lower crossover point.

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Excellent information, Josh!

 

Your goal of getting the most output out of the same size enclosures was definitely met.  The RFs look better in every way for your application. 

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The end result of both is quite close.

attachicon.gifricci ht xxx vs t319 eq'd.jpg

 

 

Excellent information, Josh!

 

Your goal of getting the most output out of the same size enclosures was definitely met.  The RFs look better in every way for your application. 

 

What am I missing? $20,000.00 vs $7,500.00 for same result. I was never a fan of the huge box requirement of the XXX driver or of stuffing it into such a radically small box but that neither here nor there in the comparo. I'm not seeing the big net gain everyone else seems to readily see... The FR at the seats is the same, neither system lacks headroom and power to drive the system is a non-issue.

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What am I missing? $20,000.00 vs $7,500.00 for same result. I was never a fan of the huge box requirement of the XXX driver or of stuffing it into such a radically small box but that neither here nor there in the comparo. I'm not seeing the big net gain everyone else seems to readily see... The FR at the seats is the same, neither system lacks headroom and power to drive the system is a non-issue.

That's the whole point the "result" is not even close to the same, the same FR is not the end all be all and does not mean they will sound the same, especially when driven hard, there are many factors that will change the resultant "sound". The RF's are a massive step up in every possible way.

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That's the whole point the "result" is not even close to the same, the same FR is not the end all be all and does not mean they will sound the same, especially when driven hard, there are many factors that will change the resultant "sound". The RF's are a massive step up in every possible way.

 

Hi Nathan,

 

Can you be more specific with what "driven hard" means in Ricci's room, how same FR can possibly sound different and any of the "many factors that will change the sound" that obviously aren't apparent to me?

 

In other threads, for example, there is howling and jeering over snake oil salesmanship claims of the benefits of using certain cables, etc., but here the terms "better in every way" and "massive step up in every possible way" are cool?

 

"Massive step up in every way"?

 

With 80-100 liters of displacement and >20KW of power there is no way to drive either system to the point of reversion to non-EQ'd response in Josh's room unless you purposely do it for no known reason.

 

He can theoretically raise the crossover if he wishes, although both traces show inaudible differences to 100 Hz. How hard would you have to push them to hear a massive difference?

 

Back when Josh was contemplating buying the XXXs he asked my opinion. I designed a sealed, DO, push/pull box of some 20 cubes net. I mentioned that 10 cubes per driver would be the minimum I would put the XXX in. There's an 8-10dB increase in sensitivity and efficiency <20 Hz with the XXX in >2X the box Josh has them in. Seems a reasonable choice to me to build better enclosures than to spend 10 grand more for drivers and claim "better in every possible way".

 

Josh said his goals were cost no object to see what he could do with the existing small boxes. I agree that he met those goals with happy results. But, to stretch that to "massive step up in every possible way" begs more specific data.

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