I would imaging that most of us, if not all, are mainly interested in how our particular Scoops fare against others, whether we make them of just buy them for our own systems.

The last set of tests I did were on my new 21's and when The Scoop was tested against the Horn cab, it was then time to test with the matching cabs that a customer was going to put underneath them. This was also completed, and quite definite comparative results were easy to read. You may recall I used my Iasys unit for signal and measuring, and the cabs were measured in 5hz steps from 20hz to 120hz. This could be 1hz steps if so desired, but 5hz seems ok.

So, this post/thread is all about making this facility available and to see whether it is possible to organise a time in which as many different cabs can be brought together and tested. It doesn't take long to do, so a lot can be done in a few hours. This is purely a frequency response test and there is no music involved.

This test would give everyone a good starting point to understand what their particular cab is doing. Everything is recorded, for our records and we each end up with a copy of results for all the cabs tested.

This offer may turn out to be a no go, but at least I am trying to do something positive. Feel free to comment.

 

so true, im happy to bring a 24" an 18" even may be able to bring a new neo  18" driver...

 

 

But you are missing the point. No scoopist use them that way. They include some magic in it that no instrument can measure. 

Random Thoughts.

Don't forget, this is only supposed to be a comparison test with one cab against another. At the end of the day, that's what people ill want to know. Don't forget, we are talking about the Scoop Bin community.

 

Rish

 

Point taken. I think thats fair. This could be a wonderful opportunity for those participating to expand their knowledge and if the results are posted on here it will give us who are not able to attend an insight as to how the cabs performed. Damn I wish i was near you guys.

 

Rish 

if you used pink noise band-limited to one octave i.e. 40-80Hz wouldn't all the inter-modulation distortion show up as noise below or above this band.

Yes it would, you will however not be able to properly assess if the products you are seeing are products of IMD or something else. Band-limited pink noise can't be generated infintely steep without ripple. It will also not be possible to assess if the out band peaks are caused by IMD or peaked response of a crossover or the cabinet itself. The easiest way to precisely test for THD, IMD or any other quantity is to do a sweep like pasi suggested. It will reveal THD,IMD, impulse reponse, frequency response, acoustical phase and indeed if a current probe is used electrical impedance as well as electrical phase. 

Just make sure the length of the sweep across the band is long enough so that enough samples can be collected for a precise FFT resolution. Just setting the FFT length of your analyser to an exact amount of samples does not mean the result wiil be accurate to this resolution if the number of samples in the input is not adequate.

 

Would be totally worth it to measure at 2.83V as well as at let's say 110dB at 4m and then compare measured quantities in an overlay.

I have adequate programming skills to quickly write up a few Matlab scripts to post process the results if I were given them in xls, csv or text files or any other comparable extension. 

'Name That Cab' 

Mr A.S.S already stated he had start AGAIN so we (you lot) can get on with the simple task of taking some audio measurements of scopes - simples! Instead we have grown men (?) saying don't bother bring your measuring equipment because my one is better, put the mic hear and not ear, to pink or not to pink should not be the ultimate question and music..... Remember that?

Imagine a group of car enthusiasts testing their chipped up, quad exhaust complete with steroid injected body kitted cars and testing them out on a rolling road - then towing their pride n joy back to it's parking space - without getting behind the wheel and driving it!! Madness!!

Why don't you just all:

* Agree on a venue

* You can bring your own test equipment - Whether that comprises of an old Realistic SPL meter, an AP rig or a laptop with some Prism converters (remember those lovely old Bruel & Kjaer units?) is up to you.

* Post up results stating the conditions of the test, what cab and which speaker was used. Obvious I know but this is Speakerplans after all...

* Music! I know the mjarity of people who posted here have said nay but just think about it.... If you are the cabinet builder it would give you a chance to add the ideal mid and tops combination (stick to 3 way as would it be fair to say a bass cab should be able to show what it can do in this format?) The music selected should be down to the cab builder to show what their system can do. With their permission others can bring their music material and 'test' the boxes with source material they are use to so that they can evaluate for their use by the old fashion method - listening. The proof of the pudding is in the eating after all..... The cab builder should bring their own amp rack to show off their cabs. 

Yes I know the music is the X factor that can upset the apple cart because you all just want to record some data about scopes so maybe you will leave it out.....

If this all goes well you could conduct the tests in field somewhere in the future. These are just my suggestions of course.

I hope this isn't throwing the cat among the pigeons but I think some of you need to take a deep breath, count to ten - and if it makes you feel better - click your heels three times.

I know that this is meant to be a scientific sound off but with out that much effort you lot can do so much more if just stop bickering like my daughters! In fact you're worse then them!!

I'm just so glad I don't encounter this on the pre-amp forums!! We are a much more civilized bunch

Just don't get your y-fronts in a twist. It's only speaker cabs.

Over to you in the SP stuido!!

I had measured the 1850 cab which contained a PD1850 speaker. The results shown indicate what the difference was between them. This is what I thought people might be interested in when applied to their own cabs.

                20    25    30    35    40    45   50    55    60    65    70    75    80

SLO21H    +5   +6   +8    +9   +6    +3   +1     0    +1   +2    +2   +1   +1

SLO21S   +11  +13 +13   +7   +2    -1    -3    -3    -2    +1    +2   +2    -1

Lev, the whole point of this is to show how good the cab is, not what kind of sound a person might prefer, or music for that matter. It's a question of suppling the tools for the job.

If other things get introduced regarding music, eq, preamps etc, the test would be about those items or methods, and wouldn't tell you much at all about the cab. Whether a person needs or wants to crank up 6-9db at 40hz would be of little interest at this stage.

There are a lot of suspect sounds around, bass thats gets overloaded, mids that aren't very clear etc. I think this happens because don't understand what is happening, or the short falls, if any, of their cabs. 

what you mention already happens at GP. So what would be the point.

People that knows how to read graphs dont actually need to hear the box to have an idea what the box can or cant do.

In this case, there are at least two groups of stakeholders - designers (tony, pasi, marjan, mykey etc) and end-users/customers (soundsystems). 

 

R&D people will probably use different criterias to evaluate whether a product under development is fit for purpose, while the end users will judge if the finished product is fit for use based on other criterias.

One should understand what purpose and which party the measurements can serve.

Indeed a wonderful tool, have used for almost three years now.

You want to hear a track with low sub bass, Ivan Gough &Jebu, Kukatu. Flat out to 31Hz dirty electronic bass.

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