...got bass?

[Jeff614]

Wow Rigtec! Excellent right up about what really makes a good speaker and the common buzzwords and catch phrases used to sell some audio equipment these days.

Thanks for taking the time to write up these posts. I've had a few decent systems and have a pretty basic understanding of the principles behind it all, but I know I learned a lot from reading your posts.

One thing I've noticed in the car audio world is smaller companies that at one time made high-end drivers and amps have sometimes given up quality for quantity and the growth of the company.

Thanks again for the write up and answers to all the questions. Still looking forward to installing my equipment. On vacation this week but possibly when I get home.

Have a great weekend!
- Jeff

 

[rigtec]

"...Thanks for taking the time to write up these posts. I've had a few decent systems and have a pretty basic understanding of the principles behind it all, but I know I learned a lot from reading your posts..."

Hi again Jeff,

It's been my pleasure to review some of my old "Prosound audio" notes and transpose or interpret them to share some liberating information w/ this forum; a great bunch of guys & gals here! I'm also very pleased to see that there are other audio system enthusiasts here besides myself to exchange with! Be sure to chime in here again when you get home from vacation; we'd be very interested to see whatcha got going in your machine, chow!

Greg

 

[mugenrios2k]

Initial a speaker company my be unwilling to give you there T/S parameters.

However if after explaining to them that you will potently be using there drive in a unique enclosure and some prodding/begging they usually will give in and send you the T/S parameters.


If a company is unwilling to give me there T/S numbers I will not use there drivers.

Of course I have ways to calculate the T/S using generators and measurement devices but buying a driver just to get the T/S is not always cost effective.. :fro:

 

[rigtec]

Initial a speaker company my be unwilling to give you there T/S parameters.
If a company is unwilling to give me there T/S numbers I will not use there drivers. Of course I have ways to calculate the T/S using generators and measurement devices but buying a driver just to get the T/S is not always cost effective.. :fro:

Hi mugenrios,

I understand your frustration w/ trying to get the info needed to move forward. A lot of really good pro-sound audio manufacturers (Cerwin-Vega, JBL, EAW, Yorkville, etc... ) conceal their build formulas for their "packaged" speaker systems to stay ahead of the competition; t'is just the game. But I don't avoid buying their high-end component drivers because of restrictions regarding unpublished data for their other 'boxed' systems. Additionally, you don't need their spec sheet to replace the 8" jbl in your truck. Just measure the stock jbl sealed box, calculate it's inner area (cuft), and find a driver to operate within that space... NO SWEAT!

 

[mugenrios2k]

Hi mugenrios,

I understand your frustration w/ trying to get the info needed to move forward. A lot of really good pro-sound audio manufacturers (Cerwin-Vega, JBL, EAW, Yorkville, etc... ) conceal their build formulas for their "packaged" speaker systems to stay ahead of the competition; t'is just the game. But I don't avoid buying their high-end component drivers because of restrictions regarding unpublished data for their other 'boxed' systems. Additionally, you don't need their spec sheet to replace the 8" jbl in your truck. Just measure the stock jbl sealed box, calculate it's inner area (cuft), and find a driver to operate within that space... NO SWEAT!

If I was just swapping; then a driver for the given volume would be ok but I would still want the T/S to calculate excursion/ 3db down point ( sealed) thermal limits to determine the best driver to "just swap out"

But i am considering doing something else with the volume in the enclosure area under the window. Long port enclosure to get additional low end with a sub sonic filter at either the x max excursion or the thermal limit at a given desired Fq.


being an mechanical engineer more data is better :nerd::nerd:



I have gotten transmission line enclosures and folded horn with transmission line hybrid in some crazy cars (where I was told that would be impossible) when I was a car stereo installer...

 

[rigtec]

"If I was just swapping; then a driver for the given volume would be ok but I would still want the T/S to calculate excursion/ 3db down point ( sealed) thermal limits to determine the best driver to "just swap out" ...being an mechanical engineer more data is better" :nerd::nerd:

"Glad to see that even engineers can have fun" :nerd: hahahaha!

 

[rigtec]

'Tricky trouble to watch out for"

Hi team,

The other day (6 to 7pm) I came home from shopping at the market; it started out just like any other day. I enjoy pumping out the tunes when in route because living in a condo, my neighbors can hear everything you do; as can I, so I don't/can't use a subwoofer system when I'm at home. So I pull into my driveway and suddenly... The subs shut-down, I mean completely! Now I'm pissed because (1) it's starting to rain, (2) it's getting dark, and (3) there was NO REASON for this to happen! I don't know about any of you but if I build a system, I know all about that system, how it works, what's in it and don't think that it should ever breakdown... lol! And I can't sleep until I know what happened and why; I mean it gets under my skin.

So I reached under the driver seat where most of the electronics are located, and felt around... I have a mental picture of where everything is e.g., RCA's, RJ-11's and 13's, USB's etc... but it didn't come back on. I installed two buttons on the center console (w/LED's) that turn the power amps ON/OFF, but the leds were off now with the buttons pushed in... "that's not good!"

Fast FWD... I knew that the next day I would need to remove the driver seat to trace the lost power supply to it's source. Upon investigation, I learned that I still had power at the driverside 'courtesy' "accessory fuse" and it's branches. But... I only had 6 volts at the miniDC HOT input (this is the sequencer that stages the amps on & off to prevent a catastrophic THUMP after initial power up spike/down drain surge). "Small blue pcb" below.

This HOT input power is constant (always on), and comes directly from the battery. So I checked the power supply at the battery and the 60A power amp 'fused' feed line that feeds Amp-2. Well... I found 12V on one side of the fuse (the line side), and only 6V on the Load side. I checked the fuse (both visually and for continuity) but it checked out 100%. Then I suspected the fuse holder because it's responsible for securing the 4ga power lines and transferring the current from the fuse to the load side. I replaced the fuse holder because that was the only thing left after the fuse checked out good. When I finished swapping the fuse holder I reconnected the battery and... holy $%*#... NFG! That fuk'd me all up. Still I had 6V at the back-end of that fuse. :noidea:

Okay, (I muttered). Let's start over. Wires, good! Fuse holder, good. Fuse,... ? Let me replace that 60A fuse anyway; even if it did check out good. Here's a shot of the fuse:


As you can see, the fuse's 'Current transfer element' isn't burned or broken and testing it for continuity proves Good! But what happened here doesn't happen very often but when it does... watch out! The fuse didn't blow... It broke(!) at the solder joint in the end cap "Just one of those 'flukie thangs' that can happen!" Later,

"Happy Motoring"! beep... beep!! (((:car:

 

[reidbailey]

Those AGU fuses are notorious for heating up and unsoldering themselves in high current applications. I recommend replacing them with a wafer type fuse that has one continuous element.

 

[Randyman...]

Those AGU fuses are notorious for heating up and unsoldering themselves in high current applications. I recommend replacing them with a wafer type fuse that has one continuous element.

Indeed. ANL for the win!!! Good for up to 300Amps...

 

[riceandpho]

this thread makes me want to put 2 more 15s in my truck, im surprised you didnt sell the jl 750/1 for a rockford t1500, they easily push out 1900+ @ 1ohm.

 

[rigtec]

"this thread makes me want to put 2 more 15s in my truck, im surprised you didnt sell the jl 750/1 for a rockford t1500, they easily push out 1900+ @ 1ohm.

Hi rice...

Well this system uses not one, but Two jl HD-750/1's for a full 1500 Wrms, and you have 'No Idea' how many dbu's that kinda energy is capable of through multiple low freq. 15's; well over 120 db's, WHICH IS ("the threshold of pain") and beyond!!!

Thanks for your post hahaha, Rgds!

 

[rigtec]

[MENTION=5149]riceandpho[/MENTION]

Is that a shot of your Black 4R in the avatar; I was trying to get a closer look at it but I couldn't find a photo on your profile pg. Do you have any pics of it on this forum(?), those wheels look Dope from what I can see... Real classy! Rgds

 

[riceandpho]

It's somewhere in the forum, look for moda 226, tirerack don't have it no more. Wish I had bought 2 more.

 

[riceandpho]

I know you have 2 750/1, just thought that if selling that for a t1500, you get some extra watts.

 

[riceandpho]

I was able to get 1554 on my t1000 amp. Great replacement from 2 jl 500/1.

 

[rigtec]

I know you have 2 750/1, just thought that if selling that for a t1500, you get some extra watts.

Hey rice,

I get it, "Good lookin' out"! But just for 'Ships & giggles'... you'll never be able to perceive (with unaided ears) the difference between say, 1500 watts and 2000 watts, or 400 watts and 500 watts (in that exact same freq band); Sound strange... Here's why. In audio science/physics, three decibels is known to be The smallest amount of change that is perceptible to the human ear. Now 3 dB is achieved only when you either... Double the amount of power in watts, or Cut the power/watts by half (50%). So if a person is listening to a stereo system with two speakers and one speaker drops out, then they just lost 3 dB of their apparent volume. Here's something else to consider... In order to double the apparent (perceived) amount of volume/loudness, you must increase the power/watts by ten times (one decade) e.g., ...for my 100 watt home theater system to be twice as loud I must, not double the power, but increase my power by an amount of ten times or 1,000 watts.

This is something I learned the hard way. As a kid and being the bass player in a local R&B band, I found that I was never loud enough to be heard over a full horn section and a drummer (with rabies). My bass amp was rated at 120 watts RMS (root mean square). My solution... get an amp with twice the power, 240 watts, and that'll do it! So I saved up my coins from every gig, and when I had enough money, I bought a bigger amp; an Ampeg with 240 watts rms. But when I played along with the band, "you guessed it"... there was no appreciable difference; but perhaps the tone. I had only raised the power by 3 decibels: "the smallest amount of change that would be 'perceptible' to anyone 'but a dog'!

I started out writing this for the purpose of the last poster; who attempted to help me with a great suggestion, which was to increase the power by a few hundred watts. But now that I'm thinking about it, this is a subject (just one of those taboos) that imho, doesn't get enough exchange in conversation. As a result, most everyone does exactly what I did yrs ago; doubles the power/watts for a (hopeful) 100% increase in apparent loudness... and then they throw away good money for an arguable return.

For those of you who may want to know more about this subject, here's a good but 'Not too complicated' explanation of how the dB system actually works and where it all started: Relationship Between Watts and dBs | Audioholics and... The Decibel (dB) Scale & Audio Rules 101 | Audioholics "Hope you'll find these interesting reads"!

Thanks riceandpho, for the inspiration to put this very important subject on the table. Best to you,

Cheers!

 

[swapmeet]

Good info rigtec, unfortunately my A.D.D. didn't allow for me to digest most of your posts I did glean some good info and agree with your theories and ideas.

Since you seem to rattle much of this off without much effort or issue, perhaps you don't mind helping me pick some equipment for my 4R? I'm looking for an unbiased opinion.

I need to utilize the factory 8" sub enclosure, which is plastic but has a impressive amount of bracing and support. I measure the air space to be .43cu/ft without a sub.
It will require a shallow mount sub.

With that being my only restriction, and assuming I only utilize a 8" sub, how do I create the largest amount of SPL or perceived sound from that package?


My research has been pointing me to DVC Kicker Comp 8's, (1 ohm or 2 ohm coils) but I can't decide on an amp.
I don't have to use that sub, just seems like the best for the size.

Thanks
P.S. try not to laugh to hard, i'm working with what I have.

 

[rigtec]

"...perhaps you don't mind helping me pick some equipment for my 4R? I'm looking for an unbiased opinion.... I need to utilize the factory 8" sub enclosure, which is plastic but has a impressive amount of bracing and support. I measure the air space to be .43cu/ft without a sub. It will require a shallow mount sub..." ...P.S. try not to laugh to hard, i'm working with what I have.

Hi swapmeet,

"Try not to laugh(?)" let me see... You knew about the importance of bracing. You knew about calculating the chamber's 'gross inner volume'... You seem to know more about this subject than you think you do, Kudos!

With that being my only restriction, and assuming I only utilize a 8" sub, how do I create the largest amount of SPL or perceived sound from that package?

Well, you start off by finding an "Ideal" driver candidate for a low frequency application to meet your requirements, which would be: a Top shelf, high sensitivity eight inch sub with a 'Shallow' frame, that will operate properly in a low inner vol. air environment. Next, we find you an amp that has about double the RMS output of the driver's power handling capacity... this is to be used as headroom. Alpine Electronics of America, Inc. So if the speaker is rated at 250W, then the amp needs to be capable of 500W rms to get the most out of the box... don't worry, the speaker is designed for that (a measurement known as the "Crest factor"!)

"...My research has been pointing me to DVC Kicker Comp 8's, (1 ohm or 2 ohm coils) but I can't decide on an amp. I don't have to use that sub, just seems like the best for the size. Thanks"

Unfortunately, I have no particular experience with 'Kicker" products. A lot of people like them and they've been around a long time. I am However, familiar with JL Audio and Alpine products; here are two subs that might interest you. 8W3v3-4 - Car Audio - Subwoofer Drivers - W3v3 - JL Audio And Alpine Electronics of America, Inc.

They are both very similar in their mounting depths (4-1/2 inches) and their 'Sensivity' (= 83.5 dB); which is likely a bit higher than the stock JBL driver. If these are too long in depth, you can use a 'shim' to move the magnetic structure away from the back of the enclosure. If that doesn't work, you could (if you feel comfortable) enlarge the mounting hole from 7 inches to 9 inches; removing ONLY one inch from each side (all the way around) of the original baffle cut-out, and install a Ten inch, shallow frame (about 3") speaker; thereby increasing your overall surface area: I explain this in depth earlier in this thread, I think on the first page.

As a result of what I've said to you here, you're going to (doubtlessly) have more questions about your project... feel free to come back here and talk about your concerns; if I can't answer you, I'm sure someone else here can!

Until then, Chow!

 

[rigtec]

Oh forgot to address part B of your post...

My research has been pointing me to DVC Kicker Comp 8's, (1 ohm or 2 ohm coils) but I can't decide on an amp.

This 'Alpine' subwoofer (mono-block amp): Alpine Electronics of America, Inc. will generate 300 watts rms into 4ohms, and 500 watts rms into 2 ohms. That said (if you're interested)... you'll want to provide a total impedance load of 2ohms to your amp. You can achieve this in two ways: (1) by running 2 four ohm voice-coils in parallel or (2), by running 2, two ohm voice-coils in series; both will result in the same 2 ohm total load.

Rgds

 

[reidbailey]

got bass?

Oh forgot to address part B of your post...


This 'Alpine' subwoofer (mono-block amp): Alpine Electronics of America, Inc. will generate 300 watts rms into 4ohms, and 500 watts rms into 2 ohms. That said (if you're interested)... you'll want to provide a total impedance load of 2ohms to your amp. You can achieve this in two ways: (1) by running 2 four ohm voice-coils in parallel or (2), by running 2, two ohm voice-coils in series; both will result in the same 2 ohm total load.

Rgds

With a mono block amp, won't you have 4 ohms with 2-2 ohm voice coils wired in series? If you have a bridged 2-channel amp with the same driver wired in series you'd see 2 ohms then.