8" vs 10" truck Tuba

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iSurfSouthChinaSea
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Re: 8" vs 10" truck Tuba

#61 Post by iSurfSouthChinaSea »

Tested and I have a bad driver. The UM8 is a dual 2ohm VC and I wired it in series to yield a 4ohm load and tested with an old MCM plate sub plate amp that I have used for years. There is some mechanical coupling internally that is hitting the cone. So while it plays the mechanical noise is a non starter. I tested at 40Hz and low volume and that plate amp is fitted with 20hz/6db Fmods so I can't comment on chuffing sounds or anything. Didn't hear anything over the mechanical coupling sounds and just called it quits.

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Seth
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Re: 8" vs 10" truck Tuba

#62 Post by Seth »

iSurfSouthChinaSea wrote: Thu May 07, 2020 1:16 am Tested and I have a bad driver.
Any update on this? How's the rest of the project coming along?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

iSurfSouthChinaSea
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Re: 8" vs 10" truck Tuba

#63 Post by iSurfSouthChinaSea »

Sorry I have not been back in awhile. I got the system done and forgot all about you guys!

I ended up using the Kicker Key amp- which comes with DSP and onboard calibration mic and costs about $200 on PE. Did I mention this $200 amp includes DSP?
It's a 4 channel and I was using it to run a full active setup- no passive x-overs. I ended getting the pricy but useful ultra thin Morel mid bass and had pods fabbed from ABS and sound dampened on floorboard but facing forward.

The factory tweeter 4x4 locations were used for a set of Morel soft dome tweets. But I had brackets printed so the tweeters would fire more forward and upward vs the naturally downward orientation. Then I let the DSP on the kicker amp do the rest. It's pretty amazing how much performance you can get from such an inexpensive amp!

I used a single DIN Kenwood Excelon- which only plays HD and multimedia and no CD transport. It sounds really good and even the HD tuner is listenable for once.

For the truck tuba I used the Dayton UM-8 and another micro amp from Audio Control AGM 2.150.

I had some help from a local boutique shop that caters to DIY crowd. They "helped" me with the stuff that I was in over my head. My idea was to make pods for the door panels. But having forward facing speakers with the DSP magic really surprised me on what was possible as far as a credible sound stage in a car.

This kei van only has a 50 amp alternator and I want to keep current draw at a minimum. I do have an AGM battery as well. So far so good. I think one of the micro amps has a 20 amp fuse and the other a 30 amp fuse.

I honestly was thinking the whole thing might be too bass heavy. But it's actually more of a studio sound with modest bass. The bass is good but doesn't make the hair stand up or anything. The driver barely seems to be moving but I really don't test it with bass tracks, as I am a big fan of listening to music ;). Mine is built to 7" depth. There are no leaks and no weird echo noises that I can hear. I tried it with a one off Eminence 8 that looks like it was made for horns- its all surround and dust cap and no visible cone and 4 ohms. It way less beefy than the UM-8 but it sounds pretty damn good in that enclosure for some reason. I really wanted to have a single 8 as my part of my theme. Overall, very happy with the musicality but would like a little more slam.

https://www.parts-express.com/morel-pow ... m--287-040
https://www.parts-express.com/kicker-ke ... --267-7610
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Seth
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Re: 8" vs 10" truck Tuba

#64 Post by Seth »

iSurfSouthChinaSea wrote: Tue Dec 01, 2020 1:18 am ...Overall, very happy with the musicality but would like a little more slam.
I was wondering about your project just the other day. Good to hear from you. What a great update :thumbsup:

Just a little warning/insight; a lot of times what people are referring to with terms like "slam" or "punch" is actually distortion that's more related to direct radiator subs and not-so-much a sound that horns produce. Not good or bad just what the case is. Sometimes I miss it a little too. But, I'd never trade the sound of smooth effortless bass to get a little dirty slamming sound.

Although, you can polish the sound of the TruckTuba quite a bit with careful EQ and Crossover selection. I found crossing it much lower than is typical helped tame the rising response and give the overall sound a desirable bottom end "tilt", then increasing the sub amp gain (and/or reduce the mid/high amp gain) so that the response produced a smooth transition at frequencies around the mid drivers highpass frequency. Don't quote me on this, but I wanna say I low passed the sub at 40Hz on an 18 or 24 dB/octave slope, or something like that. It really woke up the bottom end and gave a very pleasant curve and listening experience with pretty much any listening material.

What frequency is yours low passed at now, and what dB slope? Do you have any EQ adjustability on the sub amp?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

iSurfSouthChinaSea
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Location: Saint Petersburg, Florida

Re: 8" vs 10" truck Tuba

#65 Post by iSurfSouthChinaSea »

Slam- I always thought it was a good quality. I agree that some terms of art are probably misused. And some distortion artifacts may actually be desired. A little group delay and a peak at 60 hz are some that I think I like a little of. I do like the un-boxy effortless sound.
subsonic filter at 32 hz. The HPF is selectable at either 80 Hz or 120 Hz at a 12 dB Linkwitz-Riley slope. The mid bass drivers are in sealed enclosures but there just isn't any real airspace for them to play that low. So I must use the 120 Hz setting. The AGM 2.300 amp does not have any DSP or further bass controls. It does not even have a bass knob which is driving me nuts. Maybe I should have got the Kicker Key version for bass- which will has DSP. The AGM 1.300 allows use of a remote bass knob and "Accubass." Its my understanding that the Accubass is to correct EQ errors when the user is running it off the speaker level inputs.

The Kenwood head unit has some EQ and bass functions but they don't sound that good so I leave those flat. I seem to have a dip at 60 hz and I would prefer a peak, or at least a flat curve there. The increments for EQ skip over 60 hz. I think it goes from 50 hz to 70 hz. :(

The spacial enhance circuit does sound good for 80% of the material and I do have that engaged.

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Seth
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Re: 8" vs 10" truck Tuba

#66 Post by Seth »

iSurfSouthChinaSea wrote: Tue Dec 01, 2020 10:41 am Slam- I always thought it was a good quality. I agree that some terms of art are probably misused. And some distortion artifacts may actually be desired. A little group delay and a peak at 60 hz are some that I think I like a little of. I do like the un-boxy effortless sound.
subsonic filter at 32 hz. The HPF is selectable at either 80 Hz or 120 Hz at a 12 dB Linkwitz-Riley slope. The mid bass drivers are in sealed enclosures but there just isn't any real airspace for them to play that low. So I must use the 120 Hz setting. The AGM 2.300 amp does not have any DSP or further bass controls. It does not even have a bass knob which is driving me nuts. Maybe I should have got the Kicker Key version for bass- which will has DSP. The AGM 1.300 allows use of a remote bass knob and "Accubass." Its my understanding that the Accubass is to correct EQ errors when the user is running it off the speaker level inputs.

The Kenwood head unit has some EQ and bass functions but they don't sound that good so I leave those flat. I seem to have a dip at 60 hz and I would prefer a peak, or at least a flat curve there. The increments for EQ skip over 60 hz. I think it goes from 50 hz to 70 hz. :(

The spacial enhance circuit does sound good for 80% of the material and I do have that engaged.
Personally, I'd highly recommend the Dayton Audio DSP-408 4x8 DSP Digital Signal Processor. And if you don't already have a measurement microphone you can download a free spectrum analyzer for your phone or tablet (I use "Audio Tool") and get an inexpensive Dayton Audio iMM-6 Calibrated Measurement Microphone to use with it. Then you'll be able to dial it in pretty darn well for very little outlay.

Also, there's really no need for the subsonic filter, unless you just don't want coverage of the lower frequencies. In my car, my 2x8 8½" TruckTuba plays nearly flat all the way down to 20Hz (and lower) at the drivers rated RMS power.

The tuning I loosely quoted in my previous post was from a system I had in a Jeep Cherokee (with a 20" 2x8 TAT), which I think would have a closer interior volume to what you're vehicle has. That thing is so damn cool! I want one!

BTW, I really like the red accents on the TruckTuba. Looks great :thumbsup:
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

iSurfSouthChinaSea
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Joined: Fri Apr 17, 2020 11:13 am
Location: Saint Petersburg, Florida

Re: 8" vs 10" truck Tuba

#67 Post by iSurfSouthChinaSea »

Thanks. I thought about the Dayton DSP but if the kicker key amp includes DSP and a mic, it's a no brainer. I'm sure it's a fine unit. Ideally, I would prefer a single chassis solution- 5 channels and onboard DSP.

That's cool you are getting response down to the 20s.
I probably should had built with two 8s. What was the width (height) of your TAT in the Jeep?
I may do a tapped horn with a TB neo 8. There is an open source one made for HT applications but is roughly the size of a TAT.

Kei vans are very fun, frugal vehicles. They are just not made for the highways are are incompatible with our careless and aggressive drivers and the SUVs. But around town they are a blast. I drive extra defensively in this thing. I got this for beaches, bars, bass gear etc. I never intended to daily it but it kind has worked out that way.

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Seth
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Re: 8" vs 10" truck Tuba

#68 Post by Seth »

iSurfSouthChinaSea wrote: Fri Dec 04, 2020 10:50 am Thanks. I thought about the Dayton DSP but if the kicker key amp includes DSP and a mic, it's a no brainer. I'm sure it's a fine unit. Ideally, I would prefer a single chassis solution- 5 channels and onboard DSP.

That's cool you are getting response down to the 20s.
I probably should had built with two 8s. What was the width (height) of your TAT in the Jeep?
I may do a tapped horn with a TB neo 8. There is an open source one made for HT applications but is roughly the size of a TAT.

Kei vans are very fun, frugal vehicles. They are just not made for the highways are are incompatible with our careless and aggressive drivers and the SUVs. But around town they are a blast. I drive extra defensively in this thing. I got this for beaches, bars, bass gear etc. I never intended to daily it but it kind has worked out that way.
A compact 5 channel amp with user configurable DSP would be awesome. I like the idea of an all-in-one solution too.

A second driver will only add volume, you should be able to get response deep into the 20's too. Unless, there's an acoustic anomaly with your vehicles interior space.

Situated with the mouth on the bottom, the TAT is 22" high and 20" deep. I built mine 20" wide, the minimum for 2 (8") drivers. The original plan was to build two cabs and place them side-by-side, between the wheel wells (40"). I was quite satisfied with the one cab and weighed against the time and effort of constructing a second one, I chose not to build another one.

That's interesting that you bring up tapped horns as an option. I was looking at my TruckTuba the other day and realized that if the cab was made about 9½" wide or wider, the driver(s) could be put in the mouth panel. I don't know if having the driver in the mouth magically makes it a tapped horn or not (I suspect not, guessing there's more to it) but thought it was an interesting option that I'd try if I ever build a TruckTuba again. In any case, it's a nice protected spot for the driver(s). It would be a tight squeeze, but I think 2 drivers may just barely fit on that panel and have the magnets clear behind too... MAYBE.
Screenshot (79).png

Even if I was in your shoes, with DSP already taking control over the mids and highs... well, I kinda am in your shoes. I have a stock stereo system in my car and want to add the sub in. Anyway, I want full DSP control over the sub channel. I got a Parts Express catalog in the mail the other day. I don't usually look at junk mail, but CarterCraft was talking about his Parts Express Blast Box about the time it came. So, I flipped through the catalog for a bit and an interesting product caught my eye that I thought might be worth fiddling with. It's a DIY type of solution vs. a commercially polished end user type of product, but it may have some merit for my intended purpose (DSP control over the sub in my car). Maybe it will tickle your interest too? Dayton Audio DSPB-K DSP Kernel Board and DSPB-KE Kernel DSP Expansion 2-In 3-Out
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

iSurfSouthChinaSea
Posts: 17
Joined: Fri Apr 17, 2020 11:13 am
Location: Saint Petersburg, Florida

Re: 8" vs 10" truck Tuba

#69 Post by iSurfSouthChinaSea »

I got this for my home sub (exodus anarchy tapped horn). https://www.parts-express.com/dayton-au ... r--230-520
I haven't used it yet. But it looks like it would work in a car. It just has those cheesy 3.5mm jacks, probably because of its diminutive size.

If you want to add a sub to your factory system, the kicker key amp will include the mic and you can run it off speaker level inputs. It's pretty full proof and all the modern amps have decent line level converters.In retrospect, I probably should have got this one over the Audio Control AGM.

https://www.kicker.com/key-5001-1-chann ... -amplifier

I know many don't consider car audio a legitimate medium for enjoying music but I am not one of those. But I don't think the esoteric stuff is cost-justified for the vehicles I drive. And deafening SPL is not my thing either. I always considered Kicker to be a corny brand but they really hit it out of the park with these DSP amps in the price/performance category. But if there is another brand that does these I would want to know.

The tapped horns seem to be VERY particular about the geometry, which determines its pass band. I don't think I have any music with 20hz content, even the electronic stuff. I would be happy with non-imaginary response in mid-thirties. The speaker magnet always faces out because the first chamber is always very small.
I know folding THs is not easy. This T-6 open source design does not allow easy access to the driver. I won't expect big SPL improvement but who knows? Every car is different. But I like that effortless, resonate sound you can experience at any volume with THs. Serious math and very picky on drivers. That Tom Danley guy must be a genius. I would love to hear his TH-28 in my kei van. The TH would be built to 9.5" depth to accommodate an 8" driver (or the SB Acoustics 9" driver).

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Bill Fitzmaurice
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Re: 8" vs 10" truck Tuba

#70 Post by Bill Fitzmaurice »

SethRocksYou wrote: Fri Dec 04, 2020 12:27 pm I don't know if having the driver in the mouth magically makes it a tapped horn or not
It doesn't. A tapped horn has no rear chamber. They're considerably more difficult to design than other horns, because of the phase relationships between the front and rear waves. Most of those that I've seen aren't very good. Danley's are very good, but they're the exception. BTW, Danley didn't make the first tapped horn, although he did coin the name. I've seen prior art in patents going back to 1958.

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Re: 8" vs 10" truck Tuba

#71 Post by Seth »

iSurfSouthChinaSea wrote: Fri Dec 04, 2020 4:28 pm I know many don't consider car audio a legitimate medium for enjoying music but I am not one of those. But I don't think the esoteric stuff is cost-justified for the vehicles I drive. And deafening SPL is not my thing either. I always considered Kicker to be a corny brand but they really hit it out of the park with these DSP amps in the price/performance category. But if there is another brand that does these I would want to know.
The Kicker DSP amp looks like a great product for the average Joe. Personally, I wouldn't be satisfied not being able to tweak the settings in a GUI.

As far as car audio being legitimate or not, I suppose it depends on who you ask. There's always the guys that take things, audio in this case, to the nth degree and consider anything less than the best gear/room treatments/seating position/etc a waste of time. And on the other end of that spectrum there's the people who don't know much about it and think it's loud if it's distorting, or it sounds great because it has enough bass for cars 3 lanes over. Personally, I'm with you. I think car audio is a fantastic environment to enjoy music, if not one of the best! I really appreciate when I can get everything dialed in just right. Always puts a smile on my face. And really, what other place can you really give'r all you want, even with relative moderation, without disturbing someone else's day? (assuming you're on the highway and not a quiet neighborhood)

If you don't want to fiddle with the DSP and just accept whatever target response curve Kicker has dialed into their autotune, the 500.1 looks like a great option. 150w x1 @ 4 ohms is plenty.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Seth
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Re: 8" vs 10" truck Tuba

#72 Post by Seth »

Bill Fitzmaurice wrote: Fri Dec 04, 2020 5:08 pm
SethRocksYou wrote: Fri Dec 04, 2020 12:27 pm I don't know if having the driver in the mouth magically makes it a tapped horn or not
It doesn't. A tapped horn has no rear chamber. They're considerably more difficult to design than other horns, because of the phase relationships between the front and rear waves. Most of those that I've seen aren't very good. Danley's are very good, but they're the exception. BTW, Danley didn't make the first tapped horn, although he did coin the name. I've seen prior art in patents going back to 1958.
Another awesome little tidbit. Thanks Bill :thumbsup:
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

iSurfSouthChinaSea
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Joined: Fri Apr 17, 2020 11:13 am
Location: Saint Petersburg, Florida

Re: 8" vs 10" truck Tuba

#73 Post by iSurfSouthChinaSea »

"I think car audio is a fantastic environment to enjoy music, if not one of the best! I really appreciate when I can get everything dialed in just right. Always puts a smile on my face. And really, what other place can you really give'r all you want, even with relative moderation, without disturbing someone else's day? (assuming you're on the highway and not a quiet neighborhood) "





This is why I like it so much. :) It can be therapeutic at times with the right music. The living room offers a completely different, yet equally valid experience.

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Re: 8" vs 10" truck Tuba

#74 Post by Bruce Weldy »

I've always tested my studio mixes in my truck. For 17+ years I really enjoyed the Bose system in my Chevy Silverado - best sounding factory system I've ever heard. I don't listen to thumpty-bump music, but there was plenty of tight, fat bass for the stuff I like.

Then two months ago, I sold it and bought a brand new Chevy Truck.....and I totally miss my old system. The new one isn't even close to the sound from the old one. Not a fan of most Bose stuff, but in that truck it was stellar.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Seth
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Re: 8" vs 10" truck Tuba

#75 Post by Seth »

iSurfSouthChinaSea wrote: Sat Dec 05, 2020 1:10 am
I think car audio is a fantastic environment to enjoy music, if not one of the best! I really appreciate when I can get everything dialed in just right. Always puts a smile on my face. And really, what other place can you really give'r all you want, even with relative moderation, without disturbing someone else's day? (assuming you're on the highway and not a quiet neighborhood)

This is why I like it so much. :) It can be therapeutic at times with the right music. The living room offers a completely different, yet equally valid experience.
I completely agree.

I found the post of the tests I did on the TruckTuba in my car, which were actually on page 3 of this thread. In my car, with no EQ at all, I actually get a bit of a rising response in the bottom end. But it's mostly flat from 80 to 30 Hz.

Tested at 1.4v
20Hz 107.9dBc
25Hz 105.3dBc
30Hz 102.4dBc
40Hz 102.4dBc
50Hz 102.8dBc
60Hz 102.2dBc
70Hz 104.6dBc
80Hz 100.1dBc
90Hz 91.1dBc
100Hz 89.7dBc

It's quite a bit different (in a good way) from the in-car response curve on the sales/information page for the AutoTuba/TruckTuba

Image

I'm curious what the response is in your vehicle. If it's similar to the graph, you can see if you put a 12-24dB lowpass at 40Hz, it should result in a desirable bass response curve, giving close to equal loudness (Phons) in that region. But really, wouldn't know without measuring. Or, adjust it by ear until you like it... or auto tune with the Kicker amp.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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