Peavey 410TX Bass Cab.

[DrNomis_44]

With mobile phone apps and cheap reference microphones it's easier than it's ever been to do this stuff... I would start by measuring up the cab, port and existing speaker and using winisd to calculate the theoretical cab resonant frequency. That will help inform what might be good drivers and then you can model them.

Then I'd make up a rig for measuring impedance curves. You only really need couple of resistors, a phone, an amp and a multimeter. How tos are available on line. If you can do it accurately enough to get actual reliable measurements so much the better, but even a qualitative curve is useful. Then of course the use of a frequency response chart is obvious. The fly in the ointment is that a perfectly flat frequency response may not give a musically desirable response. I recall the surprise I got when I discovered my favourite sounding bass amp had a hpf and was rolling off low frequencies from about 80hz.

Where the experience comes in is knowing what to target for... I made a little ported 1x10 for Simon to match a high end Celestion driver that looked nice on paper, but was horribly boomy in the room. He ended up converting it to sealed. But I used the same design cab with a pair of S/H eminences for a pa rig, and although it didn't look as good to me on paper, when I used them as PA at a little local session I stopped bothering to bring a bass rig and just put my bass in the PA with the vocals. So clearly my idea of what a good bass rig should look like on paper was a mile out!

You know, if you are buying new drivers, there's a lot to be said for 32ohm ones in a 4x10... The other big decision is neo or old school magnets. I treated myself to a neo driver in my lightweight 1x15 bass cab when I got a tax refund and its wonderful. But your Peavey cab is by all accounts rather solid, and they may not make such a difference.

I have a Samsung Galaxy J2 Pro Android phone, I'm assuming that the phone is for generating a swept-sinewave signal, also have a multimeter, an analog 20Mhz Dual Trace Oscilloscope with probes, also have a bag full of 1W 1% Metal Film resistors, I've got a Peavey TKO 80 30W Bass amp combo I could probably use, can also use my laptop to generate a swept-sinewave signal too.

I'll get onto measuring the internal dimensions of the bass cab later on today when I'm more awake, I literally got out of bed about half an hour ago, still feeling a bit groggy from sleep.....might need a strong coffee to get me started...lol.

[Simon Barden]

[QUOTE=JimC;207096]With mobile phone apps and cheap reference microphones it's easier than it's ever been to do this stuff.../QUOTE]
The terms 'cheap' and 'reference microphone' simply don't go together. There are a lot of the cheap omni 'measurement microphone' types about, like the Behringer ECM8000 and its various incarnations under other names:



But without it being having a calibration file and being used with a program that can use that file to provide a flat(ish) response, you may as well use any mic with a reasonably flat and wide response.

Here's a graph comparing the frequency responses of 85 Behringer ECM8000 mics.



Whilst some are pretty flat, the majority are far from it, and without its response being checked, you have no clue what yours would be like. That graph has also been 1/3 octave smoothed, so the actual frequency response will be a lot spikier.

[DrNomis_44]

About the only decent-quality mics I have are my two Scarlett CM25 Condenser mics.


I totally understand that a speaker's impedance is far from constant all the way through it's frequency-response, and that it is due to resonances.

[dave.king1]

The head was serviced about 18 months ago, new output transistors, rebias and a couple of new resistors and caps.

There's one on eBay for $850 so that's the area that would get my attention

[DrNomis_44]

The head was serviced about 18 months ago, new output transistors, rebias and a couple of new resistors and caps.

There's one on eBay for $850 so that's the area that would get my attention

I'll see if I can get the money for it together this year.

[dave.king1]

No rush, I'm in no rush to send it on it's way and it's hiding in the cupboard along with a few guitars that don't get played often

[fender3x]

Coming late to this thread. I like the advice from JimC. Winisd is a really simple program to use, and you can use it to model a couple of different drivers. The mistake I made when I used it at first was to try to tune the cab too low. It's tempting to try to tune the cab down to 40 Hz (around a low E) or 30 Hz (around a low B), which can result in a rather boomy sounding cab. Generally commercial cabs are tuned to 50 or 60Hz, which seems to be where they sound best. Of course, as in all things, YMMV ;-)

Chances are good that the specs will not be that far off with Eminence bass drivers. They may even have been the actual OEM for Peavey as they are for a lot of Fender and other commercial cabs.* If you like how they sound in your cab...nothing to do. If you don't, you can play with the port length to see if you can dial them in a bit better.

There are a couple of things I really like about Eminence. They are very responsive to questions. I have generally heard back from them in 24 hours. They also publish all the data you are likely to need about your speaker on their website, so it's easy to compare their drivers.

I don't think you can go too wrong with BP102s. They are a great speaker. They have 6mm of xmax so it's really hard to hurt them--especially if you have 4 of them. Better than what most commercial cabs come with.

That said, you'd shave 10 KG off the weight of the cab by putting in Basslite S2020s. You'd still have 600 watts of power handling. Xmax is not quite as good, but they would have better overall frequency response, particularly at the high end, which could be good if you don't use a tweeter. Better sensitivity as well.

I've used BP102s and Deltalites (the big brother of the S2010s) and I have never had a problem. I have a couple of S2012s in boxes waiting to go into a cab that I am contemplating.

* I once got a pair of NOS bass speakers on ebay that were built for a Fender 2x10 bass cab. I discovered they were "custom built" for Fender by Eminence...when I finally got the TS specs, they were almost identical to Eminence Alphas.

[DrNomis_44]

I've decided to take JimC's advice and go and download a copy of the Winisd software, and install it on my studio desktop pc, since it should prove to be very useful for sorting-out my Peavey 410TX Bass cab, once I've got the internal dimensions, I'll also measure the diameter and length of the bass port too while I'm at it (just so happens I've got a nice digital vernier caliper I can use to do the measurements), the website says that the Winisd software is a free download too....cool.

I'm still a bit of a newbie when it comes to designing speakers, so if any other forum members would like to chime-in and offer some advice, please do, it would be much appreciated.

Like I sad in one of my previous posts, I'm willing to do whatever it takes to get my Peavey 410TX Bass cab working, and usable again.



Update:

Just got Winisd installed on my studio desktop pc, seems to be running fine so far with no major issues.



Ok, so my question is, is it possible to use Winisd to reverse-engineer my Peavey 410TX Bass cab?, I'm thinking that it is quite possible to do that if I have all the internal dimensions plus the diameter and length of the Bass port.


I decided to take some pics of the only working speaker from my Peavey 410TX Bass cab:







The last pic is a close-up of the label on one of the other three non-working speakers.

[fender3x]

Ok, so my question is, is it possible to use Winisd to reverse-engineer my Peavey 410TX Bass cab?, I'm thinking that it is quite possible to do that if I have all the internal dimensions plus the diameter and length of the Bass port.

Kind of. You can enter the box volume and port dimensions, and the number and TS specs of the drivers you plan to use. For any given set of speakers all you can really vary are the port characteristics (length and diameter). But that should be enough to give you a sense of whether a given set of drivers will work, and whether you need to do some tweaking to the port.

[DrNomis_44]

To make handling the Peavey 410TX Bass cab easier, I'm going to be buying some new heavy duty castors, to replace the existing ones from my local Bunnings store, they have a good range of castors, but that's something I may leave till later this year.