MCM 55-2421 8” driver VS everything

[Tom Smit]

Yup, I think that is a quite sufficient recovery.

[ACUA]

I have not been on here in a while , but I have been using my Tuba 45 sub horn in my truck almost daily . I found that this 18.5" wide horn fits nicely in the back seat of my 06 dodge with the rear seat folded up. There is about 62-65ish inches between the doors for about 20 inches between the horn mouth and the closed door. I have been running this set up for at least a year now and have been playing it as hard as I could while maintaining that it sounds good. I believe I can hear distortion of some kind at the last few notches on the volume knob. The max volume level reads 40 on the display and I get about a doubling of voltage about every two notches of adjustment. I find that for most music volume 36-38 is peak output with full clarity. At volume 38-40 I detect no loudness gain but a muddiness in the sound occurs. The amplifier is a Rockford Prime 750.1. I adjusted the gain structure to match the rest of the music to my liking, certainly not up past half gain as I recall. The drivers are paralleled for a base 2ohm load and the amp should be capable of 500w at 2ohms according to spec sheet.

I have said this before but there is something special about these horn-loaded subwoofer enclosures when compared to a direct radiator configuration. I noticed this way back when I built and started testing my first tuba45. At the time, I had a basic Behringer single 18" passive pa subwoofer in my possession for comparison as well as a 12" home theater sub in my house. I remember being able to test each and use an SPL meter to set the level equal and I would get very different effects beyond the sound/timbre. With the horn the sound energy seemed focused at my ears and did not interact with the environment that much, where either of the direct radiator designs that I was testing would often make things in my house rattle audibly before I felt like I was hearing the same level of sound as with the horn. I notice something similar with a horn set up in my pickup truck. I had to put a lot of work into sound deadening the cabin of my old truck to fix the tin can echo and rattles. I had multiple layers of deadening mat in the roof and doors and back panel wall to make it sound good. I have done nothing to doctor the cabin of my current truck, and I hardly get any rattling even at war level. The mirrors shake like crazy, but I don't hear rattles like I would expect. This has always fascinated me and been a major factor why I endorse these horn-loaded designs. If were to go the conventional car stereo route to achieve what I have, I would have to spent upwards of $4000-6000 for electrical upgrades, acoustical treatment, amps and subs to be as loud as my truck currently is. As it is now, I can play the system with the engine off for a long time and never hardly drag on the batteries. I only have a few hundred invested for the entire system.

I had never put a meter on the system to measure voltage output of the amp until now, I just sent it as hard as it sounded good and wondered just what these little 8" drivers could handle. For the average car audio bass head enthusiast, I am not ashamed at the output. It digs just about as low as I care to go and for the cost it just can't.

In conclusion; I measure amp voltage output at max volume(40), to be at 22.3vac. When I back the knob down to around 36-38 I get 12-15vac. If I remember correct, the recommended voltage peak on one of these MCM 8" drivers is 22-25vac. I initially wanted to compare a dual 8" setup to a lab12 which can take 50vac and series configuring two MCM 8"s gets the same power handling and roughly same cone displacement for 1/8th the cost. I was hoping that I was going to get to report that I was pushing closer to 35-40vac into the drivers but alas I am feeding them exactly what they should be able to handle. What is that then, 23v into a starting 2ohm load 250watts total peak power? Oh the money I could have saved if I had gotten into these horn-loaded designs years ago!

[himhimself]

Welcome back, ACUA! I've been out of the loop for a hot minute too, but just set up the whole rig in the backyard because that was a birthday request of one of my kids - hey papa, teach me how to set up/tear down and everything you know about sound reinforecment
Damn, the tubas sound soooooo good. We played all afternoon until the cops showed up about 8p. All cool, they said they "had to" show up due to the complaints, but we weren't violating any ordinances. I said we were planning to shut down at 9, and they said feel free to run til 10, it sounds great.
Had a couple neighbors come over with beers and hang out. And for reference, one was mowing about 1/4 mile away, with ear protection on, and could feel/hear the thump. Woohoo!!!
I realllllly want to build a couple more tubas but still trying to figure out if there is any way I could fit them into my little enclosed trailer. We shall see. But a pile of 6? Oh yeah.
Got my son looking for an indoor venue we can play around in like we used to do at the climbing gym. With indoor room gain, the tubas are ominous.
Every now and then I wonder if I should have gone with titans, but given the dj content we end up pushing, I don't think the tubas can be beat.
thanks again, Bill!!!!!!!!!!!!!!