Great thread.
Trying to measure at listening position and in stereo. The room effects and cancellations make measurements worthless from standpoint of designing a crossover. Now I measure at 0.5m and 2.0vrms on a 40in stand away from walls and take with a grain of salt data below 150hz.
Bass below that requires measurement nearfield from woofer cone and then merge scaled data.
Your speaker sensitivity can be no better then woofer minus about 5dB due to baffle step loss. The bass design defines the foundation, so spec’ mids and tweeters accordingly.
Pro audio woofers have a high sensitivity spec but typically make little to no bass below 60Hz so check curves to set the system accordingly keeping in mind the baffle step loss.
Add to your toolkit: $20 SPL meter and $50 Fluke 101 DMM to measure stuff. A gram scale and some plastic putty to use as weights to add to cone for TS parameters measurement with DATS.
Trying to measure at listening position and in stereo. The room effects and cancellations make measurements worthless from standpoint of designing a crossover. Now I measure at 0.5m and 2.0vrms on a 40in stand away from walls and take with a grain of salt data below 150hz.
Bass below that requires measurement nearfield from woofer cone and then merge scaled data.
Your speaker sensitivity can be no better then woofer minus about 5dB due to baffle step loss. The bass design defines the foundation, so spec’ mids and tweeters accordingly.
Pro audio woofers have a high sensitivity spec but typically make little to no bass below 60Hz so check curves to set the system accordingly keeping in mind the baffle step loss.
Add to your toolkit: $20 SPL meter and $50 Fluke 101 DMM to measure stuff. A gram scale and some plastic putty to use as weights to add to cone for TS parameters measurement with DATS.
My biggest mistake while building a set of speakers while in college was letting my friend install one screw in a box.
He was walking by and asked to install a screw with the drill. I said no, but he insisted, so I said, "Install one screw, but be careful!"
He forced the screw and the MDF cracked. I was perturbed, "Ah, you broke it!" He said, "Sorry dude", and went on his merry way like nothing happened.
My point is trust your instincts.
PS, I still give audio/video advice to this guy to this very day. He's still a potential monkey wrench.
He was walking by and asked to install a screw with the drill. I said no, but he insisted, so I said, "Install one screw, but be careful!"
He forced the screw and the MDF cracked. I was perturbed, "Ah, you broke it!" He said, "Sorry dude", and went on his merry way like nothing happened.
My point is trust your instincts.
PS, I still give audio/video advice to this guy to this very day. He's still a potential monkey wrench.
Ah, college-age types.
They pretty much act like know-it-alls, due to the college atmosphere.
However they tend to lack experience anyway.
You know the old saying: If you want something done, do it yourself.
In your case, this guy just wanted to play with the drill, and knew nothing about torque, wood, or screw penetration factors.
It is embarrassing to me to say this but It is so important.
Make sure you have proper hearing protection and a lot of it that is easily available at multiple locations in your work area.
Circular saws, routers, and planers are real good at damaging your ears.
(Embarrassing because I did not take these precautions early on)
Find a brand and model of tape measure that works well for you and stick to it.
Check the calibration on your tools before you use them. There is nothing like cutting a square frame on the chop saw only to find out that its set at 92 instead of 90. This includes your electrical tools as well (DATS)
If you are truly looking at this as a hobby don't forget that if a project is frustrating more than a acceptable low level change it up. You can put it on the back burner and do something else.
Jeremy
Make sure you have proper hearing protection and a lot of it that is easily available at multiple locations in your work area.
Circular saws, routers, and planers are real good at damaging your ears.
(Embarrassing because I did not take these precautions early on)
Find a brand and model of tape measure that works well for you and stick to it.
Check the calibration on your tools before you use them. There is nothing like cutting a square frame on the chop saw only to find out that its set at 92 instead of 90. This includes your electrical tools as well (DATS)
If you are truly looking at this as a hobby don't forget that if a project is frustrating more than a acceptable low level change it up. You can put it on the back burner and do something else.
Jeremy
I am enjoying this thread.
For me, the word "mistake" means an easily avoidable error.
If my third speaker project is significantly better than my first, it does not necessarily mean I made a mistake on the first project. If I created the best speaker I could on that first project, given my experience, knowledge, and skills, then I made no mistake.
A lack of perfection does not imply error. Early projects are, by necessity, training and learning exercises. It takes time and experience to develop the technical judgment to design and craft a great speaker system. We can learn a lot by studying and researching, and by following other people's progress, but eventually, we have to work through the process on our own. There are some kinds of knowledge that can only be acquired by doing. The process of "doing" is never a mistake
And to reiterate the above post
j.
For me, the word "mistake" means an easily avoidable error.
If my third speaker project is significantly better than my first, it does not necessarily mean I made a mistake on the first project. If I created the best speaker I could on that first project, given my experience, knowledge, and skills, then I made no mistake.
A lack of perfection does not imply error. Early projects are, by necessity, training and learning exercises. It takes time and experience to develop the technical judgment to design and craft a great speaker system. We can learn a lot by studying and researching, and by following other people's progress, but eventually, we have to work through the process on our own. There are some kinds of knowledge that can only be acquired by doing. The process of "doing" is never a mistake
And to reiterate the above post
Agree ! This is supposed to be fun... Don't let it become a chore, or it will start to feel like a job with no paycheck.
j.
It actually IS a job.. but the paycheck is not money but the good feeling of DIY and the enjoyment later on.
I decided to use Torx screws as i feel them to be even more secure than Allen screws after my latest attempt...
And as i am a very bad woodworker: try find advice from the men doing it for a living. I learned a lot asking simple question to carpenters around me on how to use the handtools in a way making outcomes are great.
And as i am a very bad woodworker: try find advice from the men doing it for a living. I learned a lot asking simple question to carpenters around me on how to use the handtools in a way making outcomes are great.
Consider this more of a collection of tips based on personal experience
- too low Qtc with sealed enclosures usually doesn't sound good. Nowadays I feel around 0.9 sounds best
- not enough BSC, ending up with very shouty 2 way designs
- protect your lungs from MDF, plywood, hardwood and fiberglass dust. Use gloves and long sleeves when handling fiberglass
- hot swapping amplifier leads with signal present is a bad idea. Some amps tend to blow up easier than others this way
- philips screws SUCK! Use torx screws when available
- NEVER use a screw gun or drill with t nuts. Hand thread and tighten only!
- thinner cast frame drivers like older Scanspeak and Vifa are sensitive to uneven screw torque. VC can rub if this is the case.
- newer fancy drivers with exposed VC gaps dont like exposure to fiberglass or mineral wool dust. Cover rear baskets with grille cloth.
- don't lend anyone your speakers for a party without being invited
- using a table saw is like petting a hungry lion... one day you will get bit when not paying attention
- most people will think your nuts for spending your money and time this way. Make sure your friends share the same interests.
- remember to appreciate your wife and family for putting up with your expensive, messy and time consuming hobby
- don't buy those new drivers before you finish your current project
Slipping T-nut is nightmare. Swapped woofer to existing bass box and the hole was bit too small for the frame to fit in. Spent too much time sanding and filing the hole bigger but it was still snug fit and thought to force the last millimeter in by tightening bolts, with T-nuts, and two of them got loose.. Luckily it was a big box and was able to hold down the nuts with pliers, arm through reflex port, and got the woofer out without cutting the box open. Using wood screws to attach drivers from now on. If its a proto box and wood screw holes get loose, tightened too many times, just glue them holes up / rotate the driver a bit.
Last edited:
A trick that a trim carpenter showed me for fixing stripped wood screw holes on door frames where hinges hang is to use toothpicks and white glue to stick into stripped out holes to give your screws some purchase to grip. I’ll try that on a speaker mount or baffle mount hole someday. Heavens knows I have stripped many from lazy use of power drill to drive it in (even on lowest torque setting).
I absolutely hate t nuts. They somehow all eventually become tight threaded over time. I believe this is because the thinner threaded collar tends to stretch with excess torque which changes the thread pitch and jambs the threads. Having one spin on you is a nightmare. I now epoxy a countersunk hex nut with a thick washer underneath into the inside baffle instead. Haven't had an issue since and its much cheaper.
A dedicated power screwdriver with variable speed and torque setting is great to use.
There are some larger frame drivers that have very close tolerance VC gaps ie. old Beyma, EV, Altec, Cerwin Vega, Vifa (magnesium basket) etc. I've learned my lesson using a drill as a screw driver on these chassis, even with the torque limiting clutch. Power screw driver is much better due to lack of excess torque.
Alot of baffles are also not flat and will cause a weaker cast frame to warp enough when not carefully tightened down, to the point it changes the VC alignment. Even carpeting under the frame can cause this with uneven/excess screw torque.
In some cases the VC rubbing won't occur until the driver warms up and the VC expands. That can be super frustrating and bad if the upper pole plate rubs through the winding enamel and shorts the VC windings, possibly taking the drive amp out as well. Over time the spider and surround will also sag and make the issue worse, so its super important to check for this with larger diameter vintage drivers that were stored flat on their back. If the driver came from an existing cabinet, I make sure it's clocked the same way going back in. Picky? Yes, absolutely. It's necessary to be this way if you're dealing with irreplaceable drivers you can't get parts for.
Alot of baffles are also not flat and will cause a weaker cast frame to warp enough when not carefully tightened down, to the point it changes the VC alignment. Even carpeting under the frame can cause this with uneven/excess screw torque.
In some cases the VC rubbing won't occur until the driver warms up and the VC expands. That can be super frustrating and bad if the upper pole plate rubs through the winding enamel and shorts the VC windings, possibly taking the drive amp out as well. Over time the spider and surround will also sag and make the issue worse, so its super important to check for this with larger diameter vintage drivers that were stored flat on their back. If the driver came from an existing cabinet, I make sure it's clocked the same way going back in. Picky? Yes, absolutely. It's necessary to be this way if you're dealing with irreplaceable drivers you can't get parts for.