My first titan

[Chris_Allen]

I couldn't resist getting the Titan 48 up and running before it was finished. I hooked it up with a pair of Mackie 1530's (500W) that were gathering dust(saw) in the corner of the garage.

Utilising the 75Hz crossover that is built into the Mackie CFX12 mixer I connected it the sub channel into the left channel of a Yamaha CP2000 power amp. The CP2000 is rated at 650W into 4Ohms, 450W into 8Ohms so I guess it would drive around 350W into 10Ohms.

I used my MP3 player to do a quick test. The Mackies don't have a volume control, so they always run at full power.

On first listening there is a bit of an inbalance of power, the sub need to be louder in the mix, but there wasn't anything I could do as the power amp was on full volume and I didn't want to use the EQ on the mixer.

My first impression was of absolute amazement. I could 'feel' the bass leaving the speaker, but there were no signs of muffling. The bass was clean and pure. The sense of elation was tremendous. Not only did the speaker work! but the sound it produced was fantastic.

I am not a wood worker by any means, and the quality of the ply wasn't great, but it has all come together and I could not be more pleased. I am going to give a more in depth view once I have finished the cab and have tested it with my crossover.

Thanks to everyone who has provided the invalueable input so far.

The Titan 48 is loaded with a Kappalite 3015LF and has an internal width of 29.5".

Chris.

[bgavin]

On first listening there is a bit of an inbalance of power, the sub need to be louder in the mix

This surprises me. The amp has sufficient power to drive the T48 to full power, so it should be quite loud.

Q: are the tops running full range?

If so, there is most likely a bass cancellation between Tops and T48, reducing the apparent bass volume.

I notice you omitted the mouth bracing and applied finish. This leaves large areas unbraced.

[DJ Big Ronn]

Calkin, You will be really pleased with your Titans. I dont know if you are planning on building another one, but please do. Last night I Dj'd the first home game of the season of our local high school, the sound was absolutly stunning. Last year I only had 2- DR250's, this year I had all four with two 24 wide T-48's. I had to put them standing upright side by side with the tops stacked on top of them because of inclement weather. It was fun to hear people talking about the grass waving in front of the T-48 mouths. Because of the rain our band only brought out horns and they were sorely out matched by the other team. This is going to sound a little hard to believe, but I starting playing some LSU marching band music and ended up competing with their band in between plays. Just like the enzyte commercial, a had a great swelling of pride to know that my 1200 dollar home built speakers were able to play at that level. The band director passed by after the game and shook his head and said "man you"re killing me with those things". I think I'll bring the other two T-48's for Homecoming put them in "V" formation with a "V" plate and really have some fun If you build them, they will come.

[Chris_Allen]

The main point is that I tested it in the garage with the door shut, so there is plenty of reflection in the room (concrete walls, concrete floor, asbestos roof!). I've now plugged in the crossover and set it at 120Hz. I need to take 4 dB out of the tops to make it sound balanced. It's almost deafening in the garage when the mixer is outputting 10dB below the zero level on the main led meter.

I appear to be experiencing resonance at a certain frequency, I believe it's around 70-80Hz, but's that most likely a room fundamental. I don't have any of my EQs here so I can't be sure. The titan certainly feels like it has the ability to crank way louder than I dare turn it up. I need a much bigger room to test.

I've just changed the polarity (I didn't mark the cable!) and I think it sounds better, again, hard to tell, really need an A/B. Recall reading that the Eminence 3015 connectors might be backwards in terms of Red/Black. The cables on my multimeter aren't long enough to test the cable, just going to extend it to test. Is it normally Speakon 1+ to Red?

Strange thing, I've been listening to the MP3 player through the speakers for the past 10 minutes and I'm sure the bass is getting louder....

I am going to build a second 29.5" titan, but probably also build another 2 but 18" wide with 12" speakers to drop the impedence. This also gives me the option of a portable bass rig.

What are the characteristics of a leak? Is it complete loss of power at all levels or a decline only when at higher input levels?

Thanks.

Chris.

[Bill Fitzmaurice]

The main point is that I tested it in the garage with the door shut, so there is plenty of reflection in the room (concrete walls, concrete floor, asbestos roof!)

One of the worst possible testing scenarios. Try it outdoors, cabs against the house, listen from 50 feet away, it will be quite different.

What are the characteristics of a leak?

No bottom. I think once you get the second T48 on line and V couple them in a room large enough for them to breathe your main concern will be how soon you can build some DRs or OTops, because the Mackies won't be able to keep up.

[bjhueni]

Strange thing, I've been listening to the MP3 player through the speakers for the past 10 minutes and I'm sure the bass is getting louder....

I had a similar experience with mine. They seemed to have a "break in" period. After running them a few minutes I turned them down, a few more minutes and down some more. I was also testing in my small garage ( with the door open ) and I didn't want to drop the glass out of my old door.

I might hook them up outside today with the S115Vs and give them a better test drive. I also want to run them through the DRPA instead of the LPF of my mixer.

[DJ Big Ronn]

Damn Horns, my T-48's always sound better outside.

[Chris_Allen]

Well, it certainly has plenty of bottom.

Need to get a sin wave generator to test it properly. I should have realised that the Mackies are always going to sound louder in an enclosed space.

I've had another night to sleep, so I'll get another perspective again this morning, now the Mrs has gone out

I'm not looking forward to building the DR250's, so I might start with a pair of OTs. I just think the DR's look a lot cooler, and of course the better frequency response.

Edit: Just reviewed the SPL charts, and there really isn't anything between them except for cost of drivers and impedence.

Chris.

[Tim A]

I should have realised that the Mackies are always going to sound louder in an enclosed space.

They're going to be louder anyway the way you have them set up. Do like Bill says, outdoors, and spread the Mackies apart by 16-20', like you'd have them for a gig.

Then just for shits and giggles, turn the sub toward the wall.

[wannabe]

I think its the fact that the DR's (EQ'd properly) will sound better than the OT's, reguardless of the SPL. The DR250's might be the same, but the 280, 290 and 300 are louder. I don't have either, so I can't really say what's better, but with the DR250's, you can stack them and have them get louder, I believe.

[LelandCrooks]

I think its the fact that the DR's (EQ'd properly) will sound better than the OT's, reguardless of the SPL.

+1. Heard both. Not much, but it's there.

[Chris_Allen]

I still find the prospect of building DRs daunting at the moment. So I might start with the OTs then build the DRs if I have sufficiently developed my skills with a tape measure.

Armed with a tone generator software the titan outputs wonderfully down to 30Hz. I ran pink noise to test the power output of amp, with the limiter on the crossover set to +6, it's enough for the power amp clipping light not to flash. Measuring the output with a multimeter on an unloaded output I got around 35V. Unfortunately, i'm not sure what this means. Does it mean that as long as I have the limiter in place at +6, I could run the amp on full power and not worry about the mix blowing the speaker?

I keep reading the posts about it, but the penny still hasn't dropped and I am reluctant to put them into service worrying that one is going to pop.

And if there is anyone who lives near me, willing to help me through a DR, it would be greatly appreciated

Thanks.

Chris.

[Bill Fitzmaurice]

Measuring the output with a multimeter on an unloaded output I got around 35V. Unfortunately, i'm not sure what this means. Does it mean that as long as I have the limiter in place at +6, I could run the amp on full power and not worry about the mix blowing the speaker?

35v into the nominal 10 ohm T48 is 122 watts. If you're able to send any level signal into the amp and it never exceeds 35v then you definitely would never blow the driver. The 3015LF can take peaks of up to 67 volts.

[Chris_Allen]

So am I correct in the use of the limiter? or should I allow the peak lights on the power amp to flash?

I realise that other people use the limiter to ensure that they never pass the 67 Volt barrier. Am I just clearly unaware of the power that is produced by these speakers! If I drove these speakers at the 122Watts that you describe would be so obscenely loud. I can't imagine how loud 67Volts would be, or is this the entire point that everyone is trying to make?

So if Yamaha are saying that the CP2000 can output 450Watts at 8Ohms, why am I only getting 122Watts with a high mix level? there must only be 6 db of headroom left (absolute maximum) which would be well within the clipping area, is that enough to triple power output which is still below the thermal limit of the speaker? saying that 3db doubles the power output (based on an exponential curve) this would be roughly correct.

Thanks.

Chris.

[Bill Fitzmaurice]

So if Yamaha are saying that the CP2000 can output 450Watts at 8Ohms, why am I only getting 122Watts with a high mix level?

Either their clipping indicator is set very conservatively or their power rating is very optimistic.