Twin T30 build - Xmas 2011

[beofservice]

Re: break in: now that they have been used for about 10 hrs they are probably broken in. If not they will be after the next gig or two.

In comparison with the big box subs they replaced, the new subs have better (deeper) bottom and seem to "excite" the room better. However, at 60-100hz I think the old big box subs played louder. This is rather like the tradeoff between the Titan and the Tuba. I chose the Tuba design because my son plays Dubstep, and I'm getting deep bass that wasn't there with the old speakers.

We ran the speakers in stereo because when we pressed either the "summed" or "mono" buttons (or both) on the crossover the subs either didn't sound as good or didn't play as loud. It was not at all difficult to distinguish either. Press the button, sound gets quieter and/or muddier. Note that we also tried switching the polarity in case I messed up a cable end or something, but then the sound got way quieter (polarity was not the problem)!

Finally, note that the EV Force speakers retailed at around $1,100/pair back in the day. I bought this pair used, with a blown compression driver for $150 and installed a new compression diaphragm and repainted the grills. Their efficiency rating is around 100db/W at 1 M, and I expect the efficiency of the old big box subs is similar. Don't forget that for the average person, louder sounds better, and if the old speakers play louder they are going to sound somewhat "better", at least in the frequency range where they excel. I have basically traded a little volume for better frequency response, though I really need a little more power in the amp and a limiter configured before I can say that for sure.

Thanks for your input.

Gary

[Bill Fitzmaurice]

However, at 60-100hz I think the old big box subs played louder.

Perhaps. It's not unusual to trade sensitivity for low end. The other thing is that even though crossed over below 100Hz direct radiators produce a lot of modulation distortion as much as two octaves higher, giving the subjective impression of belng louder. T30s don't.

[beofservice]

As a way to get into the DJ thing inexpensively we had started out with all used gear. That meant large heavy equipment, sometimes sonically compromised too. Last week one of the amps started to act up, and so we bought a new Peavey IPR 1600 which is now driving the T30s. Lets just say the Peavey is a significant improvement over the old (and monsterously heavy) Altec, mostly due to its greater power. The Altec was only rated 120 wpc into 8 ohms, where the Peavey is rated at 300. Where the Altec was running near its limits and having trouble driving the T30s to their voltage limits, the new amp is loafing along with lots of headroom. We still need to install a limiter in order to be able to drive the T30s safely closer to their limits, but they sound significantly better on this new amp already. At the frat party this past Saturday they were crazy loud!

A huge side benefit to this swap is that the amp rack can now be carried by one person without risk of hernia or ruptured disk. The Peavey is only about 7 lbs, using a switching power supply to save weight and cost. Would have been nice if it offered more connection options (no XLR, no speaker binding posts, just Speakon and 1/4 inch in and out). The blue light inside is kind of hokey too, like it should be in a car trunk... The overall feel is kind of cheap. It works well so far though. Let's hope it holds up with no service issues.

[88h88]

Would have been nice if it offered more connection options (no XLR, no speaker binding posts, just Speakon and 1/4 inch in and out).

My version has combination inputs, it accepts 1/4" and XLR... I'm in the UK but this US site has the same: (big pic) http://c804221.r21.cf2.rackcdn.com/cata ... 1600_2.jpg

Fully agreed on the LEDs though, it looks like some boy racer bullshit amp when it actuality it's awesome.

[doncolga]

Hey,

Do you know how many volts you're sending to your drivers? I'm not sure but aren't the drivers you have able to do about 30 volts each? That should make some respectable SPL.

[beofservice]

My version has combination inputs, it accepts 1/4" and XLR... I'm in the UK but this US site has the same: (big pic) http://c804221.r21.cf2.rackcdn.com/cata ... 1600_2.jpg

DOH! (smacking sound). Looks like you are right.

I thought I had verified that when I ordered the amp, but the room where we were setting up was kind of dark and I didn't recognize the 3 pin holes in the input connectors. I figured I must have been wrong about the specs of the amp. The manual for the amp only comes on CD (or online) so I couldn't quickly look at it. We used some XLR to 1/4 patch cables, but we should switch back to the full XLR balanced cables next time.

Thanks 88.

[beofservice]

Hey, Do you know how many volts you're sending to your drivers? I'm not sure but aren't the drivers you have able to do about 30 volts each? That should make some respectable SPL.

We (he, the DJ) is using a small analog multimeter to monitor voltage levels. We have been using 30VAC as our limit, and at that voltage it depends on the room size how loud they sound. In the room he was in on Saturday (small room but high ceiling) he was running the amp at only 15-20v and it was very loud. The previous amp was barely able to put out the 30v without limiting. It would have worked OK in this room. The new amp was able to handle it with the attenuator set about half way.

It is unfortunate the new amp doesn't have binding posts that can be used to easily measure the voltage. What we had to do was to plug a bare 1/4" plug into the speaker jack and check voltages there. That works OK for a static measurement, but without a limiter we kind of like to monitor the voltage during operation too.

The bare 1/4" plug can be plugged into the parallel jack on the back of one of the subs and measurements can be taken there, but then the DJ can't see the meter from his operating position. I could rig up a "measurement cable" with 1/4" at one end and alligator clips at the other. That would work, but obviously we need to add a limiter to the rig so we can set it once and then relax.

Thanks.

Gary

[Bill Fitzmaurice]

We (he, the DJ) is using a small analog multimeter to monitor voltage levels.

I'd keep it at 20v until you get a limiter. A transient pulse can take out a driver in an instant. By the time you see the reading on the meter it's too late because it already happened.

[beofservice]

I'd keep it at 20v until you get a limiter. A transient pulse can take out a driver in an instant. Buy the time you see the reading on the meter it's too late because it already happened.

Thanks Bill.

[osse]

We (he, the DJ) is using a small analog multimeter to monitor voltage levels.

I'd keep it at 20v until you get a limiter. A transient pulse can take out a driver in an instant. By the time you see the reading on the meter it's too late because it already happened.

Happened to me a couple of times with the 3012lf.. nema problema